Comprehensive University Chemistry and Biochemistry Notes

Atomic Structure and Quantum Mechanics

• Subatomic Particles:

  • Protons ($p^+$): Positively charged particles located in the atomic nucleus, carrying an elementary charge of $+1.602 \times 10^{-19}\text{ C}$.

  • Neutrons ($n^0$): Electrically neutral particles located in the atomic nucleus.

  • Electrons ($e^-$): Negatively charged particles located in the electron cloud surrounding the nucleus, carrying an elementary charge of $-1.602 \times 10^{-19}\text{ C}$.

  • Nucleon Number ($A$): The total number of protons and neutrons in the nucleus ($A = Z + N$).

  • Proton Number ($Z$): The number of protons in the nucleus, defining the chemical identity of the element.

  • Neutron Number ($N$): The number of neutrons in the nucleus.

  • Nuclide: An atomic species characterized by specific values of proton number $Z$ and nucleon number $A$.

  • Isotopes: Atoms of the same element with identical proton numbers $Z$ but different neutron numbers $N$ (and thus different nucleon numbers $A$).

• Quantum Numbers:

  • Principal Quantum Number ($n$): Determines the energy level of the electron and the size of the atomic shell. It takes positive integer values ($n = 1, 2, 3, \text{...}$) corresponding to shells labeled $K, L, M, N, O, P, Q$.

  • Azimuthal (Subshell) Quantum Number ($l$): Determines the shape of the atomic orbital. It takes values from $0$ to $n - 1$, corresponding to subshells labeled $s$ ($l = 0$), $p$ ($l = 1$), $d$ ($l = 2$), and $f$ ($l = 3$).

  • Magnetic Quantum Number ($m$): Determines the spatial orientation of the orbital in space. It takes integer values from $-l$ to $+l$ including $0$. The total number of orbitals in a subshell is $2l + 1$.

  • Spin Quantum Number ($s$): Characterizes the intrinsic angular momentum (rotation) of the electron around its own axis. It is a property of the electron itself, not the orbital, and takes two values: $s = +\frac{1}{2}$ or $s = -\frac{1}{2}$.

• Electron Shell Capacities:

  • Maximum electron capacity of a single shell $n$ is given by the formula $2n^2$.

  • $K\text{ shell } (n = 1):$ Subshell $1s$ ($1\text{ orbital}$) $\rightarrow$ maximum $2\text{ electrons}$.

  • $L\text{ shell } (n = 2):$ Subshells $2s$ ($1\text{ orbital}$) and $2p$ ($3\text{ orbitals}$) $\rightarrow$ maximum $8\text{ electrons}$.

  • $M\text{ shell } (n = 3):$ Subshells $3s$ ($1\text{ orbital}$), $3p$ ($3\text{ orbitals}$), and $3d$ ($5\text{ orbitals}$) $\rightarrow$ maximum $18\text{ electrons}$.

  • $N\text{ shell } (n = 4):$ Subshells $4s, 4p, 4d, 4f$ $\rightarrow$ maximum $32\text{ electrons}$.

• Rules for Filling Electron Orbitals:

  • Pauli Exclusion Principle: No two electrons in a single atom can have the same set of all four quantum numbers ($n, l, m, s$). They must differ in at least their spin quantum number. Therefore, an orbital can hold a maximum of 2 electrons with opposite spins.

    • Maximum capacity per subshell: $s\text{ level} = 2 e^-$, $p\text{ level} = 6 e^-$, $d\text{ level} = 10 e^-$, $f\text{ level} = 14 e^-$.

  • Hund's Rule: Degenerate orbitals (orbitals with identical energy, such as the three $p$ orbitals) are occupied first singly by electrons with parallel spins before pairing up with a second electron of opposite spin. Unpaired electrons minimize inter-electronic repulsion and lower atomic energy.

  • Aufbau (Minimum Energy) Principle: Orbitals are filled in order of increasing energy. Orbitals with a lower sum of $n + l$ are filled first. When two orbitals have the same value of $n + l$, the orbital with the lower principal quantum number $n$ is filled first.

  • Filling Order: $1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d$

  • Abbreviated Electron Configuration: The core configuration is abbreviated using the symbol of the preceding noble gas in square brackets, followed by the valence shell electrons. Example for Boron ($Z = 5$): $1s^2 2s^2 2p^1$ or $[\text{He}] 2s^2 2p^1$.

Chemical Bonding and States of Matter

• Chemical Bond Formation:

  • A chemical bond forms when atoms approach each other and overlap their valence orbitals, producing an energetically favorable state with lower potential energy.

  • Valency (Vaznost): The number of covalent bonds an atom forms in a compound, which equals the number of shared electron pairs. Determined via valence shell configuration in the ground or excited state (e.g., carbon is tetravalent due to excitation $1s^2 2s^1 2p_x^1 2p_y^1 2p_z^1$).

  • Octet Rule: Elements in the 2nd and 3rd periods tend to share electrons until their valence shell achieves a noble gas configuration containing 8 electrons ($ns^2 np^6$).

• Types of Covalent Molecular Orbitals:

  • $\text{Bond } \text{σ (sigma):}$ Electron density is concentrated directly along the internuclear axis connecting the bonded nuclei. Formed by head-on overlap of $s\text{--}s$, $s\text{--}p$, $s\text{--}d$, $p\text{--}p$, $p\text{--}d$, or $d\text{--}d$ orbitals.

  • $\text{Bond } \text{π (pi):}$ Electron density is concentrated above and below the internuclear axis in a plane passing through both nuclei. Formed only after a $\text{σ}$ bond is established by parallel overlap of $p\text{--}p$, $p\text{--}d$, or $d\text{--}d$ orbitals. Bonds containing $\text{π}$ components (multiple bonds) are weaker and chemically more reactive than single $\text{σ}$ bonds.

• Electronegativity and Bond Polarity:

  • Electronegativity ($x$): The empirical measure of the ability of a chemically bonded atom to attract shared electron pairs toward itself.

  • Nonpolar Covalent Bond: Difference in electronegativity $Δx < 0.4$. Shared electron pair is evenly distributed between the bonded atoms.

  • Polar Covalent Bond: Difference in electronegativity $0.4 ≤ Δx ≤ 1.7$. Shared electron pair is shifted toward the more electronegative atom, inducing partial charges ($δ^+$ and $δ^-$).

  • Ionic Bond: Difference in electronegativity $Δx > 1.7$. Complete transfer of one or more valence electrons occurs, creating discrete cations and anions bound by electrostatic attraction.

• Metallic Bonding:

  • Occurs in solid metals. Metal cations are arranged in a regular crystal lattice surrounded by delocalized valence electrons known as an electron gas.

  • Confers electrical conductivity, high thermal conductivity, ductility, and malleability.

• Intermolecular Forces:

  • van der Waals Forces: Weak intermolecular attractions resulting from permanent, induced, or instantaneous dipoles. They mediate interactions between nonpolar or polar molecules.

  • Hydrogen Bonding (Hydrogen Bridge): A strong electrostatic interaction between a hydrogen atom covalently bound to a highly electronegative atom ($\text{F, O, N}$) bearing a lone pair, and a lone pair on a second electronegative atom. Represented by dotted lines ($\text{H–F}\text{⋯}\text{H–F}$). Bond energy ranges from $10\text{ to }30\text{ kJ }mol^{-1}$ (compared to single covalent bonds at $150\text{ to }300\text{ kJ }mol^{-1}$). Substantially increases boiling points.

• Crystal Structures:

  • Ionic Crystals: Composed of alternating cations and anions maximizing electrostatic interactions. Brittle, high melting points ($600\text{--}2000\text{ }^∘\text{C}$), conductive only when molten or dissolved (e.g., $\text{NaCl}$).

  • Atomic (Covalent) Crystals: Composed of atoms held together in a continuous 3D spatial network of covalent bonds. Extremely hard, insoluble, nonconductive, extremely high melting points (e.g., diamond melting at $3800\text{ }^∘\text{C}$).

  • Molecular Crystals: Regular arrangements of discrete molecules held together by van der Waals forces or hydrogen bonds. Soft, low melting points, nonconductive (e.g., iodine $\text{I}_2$).

  • Amorphous Solids: Non-crystalline solids lacking long-range periodic order (e.g., glass, soot).

  • Polymorphism: The ability of a chemical compound to crystallize in different crystal lattice forms (e.g., $\text{CaCO}_3$ as orthorhombic aragonite or rhombohedral calcite).

  • Allotropy: The existence of a pure chemical element in multiple structural modifications (e.g., carbon as hexagonal graphite or cubic diamond).

  • Isomorphism: The ability of distinct chemical substances with similar chemical composition to crystallize in identical lattice systems and form mixed crystals (e.g., heptahydrate sulfates of $\text{Mg}^{2+}$, $\text{Zn}^{2+}$, and $\text{Ni}^{2+}$).

Chemical Reaction Kinetics, Thermodynamics, and Equilibrium

• Reaction Kinetics:

  • Reaction Rate ($v$): Defined as the change in molar concentration of a reactant or product per unit time.

  • Collision Theory: For a reaction to occur, reactant particles must collide with a favorable spatial orientation and possess a minimum energy known as the activation energy ($E_a$) to overcome repulsive forces and break existing bonds.

  • Activated Complex: An unstable intermediate state of maximum potential energy formed during a successful particle collision, where original bonds are partially broken and new bonds are partially formed.

  • Guldberg-Waage Law (Rate Law): For an elementary reaction $aA + bB \rightarrow cC + dD$, the reaction rate is proportional to the product of the molar concentrations of reactants raised to their stoichiometric powers: \n\nv = k imes [A]^a imes [B]^b\n\n

  • Arrhenius Equation: Relates the rate constant $k$ to temperature: \n\nk = A imes e^{- rac{E_a}{R imes T}}\n\n

• Catalysis:

  • Catalyst: A substance that increases the rate of a chemical reaction by changing its reaction pathway to one with a lower activation energy ($E_a$), remaining chemically unchanged at the end of the reaction.

  • Homogeneous Catalysis: Reactants and catalyst reside in the same physical phase (e.g., liquid acid catalyzing a liquid mixture).

  • Heterogeneous Catalysis: Catalyst and reactants reside in different physical phases (e.g., solid iron catalyst in gaseous ammonia synthesis: $3H_{2(g)} + N_{2(g)} \rightleftharpoons 2NH_{3(g)}$).

  • Catalytic Cycle Stepwise Mechanism: \n\n1. ext{ } A + K ightarrow AK\n\n \n\n2. ext{ } AK + B ightarrow C + K\n\n

  • Inhibitors (Negative Catalysts): Substances that increase activation energy $E_a$, thereby decreasing reaction rate.

  • Catalytic Poisons: Substances that irreversibly bind to and block active sites on a catalyst, destroying its activity.

  • Stabilizers: Substances that react with free-radical intermediates in chain reactions to terminate the chain sequence.

  • Autocatalysis: A reaction sequence where one of the reaction products acts as a catalyst for the process.

• Thermochemistry:

  • Molar Reaction Heat ($Q_r$): Heat absorbed or released by a system when 1 mole of elementary reaction transformations occurs under stoichiometric conditions.

  • Isochoric Process ($V = \text{const}$): Heat exchanged equals the change in internal energy of the system ($Q_V = ΔU$).

  • Isobaric Process ($p = \text{const}$): Heat exchanged equals the change in enthalpy of the system ($Q_p = ΔH$).

  • Standard Conditions: Temperature $T = 298.15\text{ K}$ ($25\text{ }^∘\text{C}$) and pressure $p = 101.325\text{ kPa}$.

  • Exothermic Reaction: Heat is released into the surroundings ($ΔH < 0$).

  • Endothermic Reaction: Heat is absorbed from the surroundings ($ΔH > 0$).

  • First Law of Thermochemistry (Lavoisier-Laplace): The enthalpy change of a reverse reaction is equal in magnitude but opposite in sign to the enthalpy change of the forward reaction.

  • Second Law of Thermochemistry (Hess's Law): The total enthalpy change of a chemical reaction depends only on the initial and final states of the reactants and products, and is independent of the specific reaction path taken.

  • Standard Enthalpy of Formation ($ΔH_f^∘$): Reaction enthalpy for the formation of 1 mole of a compound in its standard state from its constituent elements in their standard states. $ΔH_f^∘$ of pure elements equals zero.

  • Standard Enthalpy of Combustion ($ΔH_c^∘$): Reaction enthalpy for the complete oxidation of 1 mole of a substance in its standard state to its ultimate oxidation products. $ΔH_c^∘$ of ultimate products (e.g., $\text{H}_2\text{O}_{(l)}$, $\text{CO}_{2(g)}$) equals zero.

  • Enthalpy Calculations: \n\nΔH^∘ = ∑ ν{prod} imes (ΔH_f^∘){prod} - ∑ ν{react} imes (ΔH_f^∘){react}\n\n \n\nΔH^∘ = ∑ ν{react} imes (ΔH_c^∘){react} - ∑ ν{prod} imes (ΔH_c^∘){prod}\n\n

• Chemical Equilibrium:

  • Dynamic Equilibrium: Achieved when the rates of the forward and reverse reactions become equal ($v_f = v_r$), keeping reactant and product concentrations constant over time.

  • Equilibrium Constant ($K_c$): Expressed as the ratio of product equilibrium concentrations to reactant equilibrium concentrations, each raised to its stoichiometric coefficient: \n\nK_c = rac{[C]^c imes [D]^d}{[A]^a imes [B]^b}\n\n

• Protolytic (Acid-Base) Equilibria:

  • Autoprotolysis of Water: $\text{H}_2\text{O} + \text{H}_2\text{O} \rightleftharpoons \text{H}_3\text{O}^+ + \text{OH}^-$.

  • Ionic Product of Water ($K_w$): At $25\text{ }^∘\text{C}$, $K_w = [\text{H}_3\text{O}^+] \times [\text{OH}^-] = 10^{-14}$.

  • pH Scale: Defined as the negative common logarithm of the hydronium ion activity/concentration: pH = -\text{log}[\text{H}_3\text{O}^+]$.\n * Acidic solution: [ ext{H}_3 ext{O}^+] > [ ext{OH}^-] ightarrow pH < 7\n * Neutral solution: [ ext{H}_3 ext{O}^+] = [ ext{OH}^-] ightarrow pH = 7\n * Basic solution: [ ext{H}_3 ext{O}^+] < [ ext{OH}^-] ightarrow pH > 7\n * **Neutralization:** Reaction between an acid and a base producing a salt and water: ext{H}_3 ext{O}^+ + ext{OH}^- ightarrow 2 ext{H}_2 ext{O}.\n * **Salt Hydrolysis:** Reaction of salt ions with water:\n * *Salt of strong acid + weak base* (e.g., ext{NH}_4 ext{Cl}$):$ ext{NH}_4^+ + ext{H}_2 ext{O} ightleftharpoons ext{NH}_3 + ext{H}_3 ext{O}^+ ightarrow **Acidic solution**.\n * *Salt of weak acid + strong base* (e.g., ext{CH}_3 ext{COONa}$):$ ext{CH}_3 ext{COO}^- + ext{H}_2 ext{O} ightleftharpoons ext{CH}_3 ext{COOH} + ext{OH}^- ightarrow **Basic solution**.\n * *Salt of strong acid + strong base* (e.g., ext{NaCl}$): Neither ion hydrolyzes$ ightarrow **Neutral solution**.\n * *Salt of weak acid + weak base* (e.g., ext{CH}_3 ext{COONH}_4$): Both ions hydrolyze$ ightarrow$**Approximately neutral** (pH depends on relative dissociation constants$K_a$vs$K_b).\n\n\n# Oxidation-Reduction Reactions and Electrochemistry\n\n* **Redox Processes:**\n * **Oxidation:** Process in which an atom loses electrons, increasing its oxidation number.\n * **Reduction:** Process in which an atom gains electrons, decreasing its oxidation number.\n * **Oxidizing Agent:** A substance that accepts electrons from another species, causing its oxidation, and becomes reduced itself.\n * **Reducing Agent:** A substance that donates electrons to another species, causing its reduction, and becomes oxidized itself.\n\n* **Beketov Reactivity Series of Metals:**\n * Arranged by increasing standard electrode potential E^∘ relative to the standard hydrogen electrode:\n

$\text{K, Ca, Na, Mg, Al, Zn, Sn, Pb, H, Sb, Cu, Ag, Hg, Au}$

\n * **Non-Precious Metals (Left of Hydrogen):** Have negative standard reduction potentials. Capable of displacing hydrogen gas from dilute non-oxidizing acids ( ext{M} + 2 ext{H}^+ ightarrow ext{M}^{2+} + ext{H}{2(g)}).\n * **Precious Metals (Right of Hydrogen):** Have positive standard reduction potentials. Incapable of displacing hydrogen from acids; dissolve only in strong oxidizing acids (e.g., ext{HNO}_3) or aqua regia.\n * Any metal standing further to the left in the series possesses stronger reducing ability and can reduce cations of any metal positioned to its right.\n\n* **Galvanic Cells:**\n * A device converting spontaneous redox chemical energy into electrical energy.\n * **Anode:** Negative electrode where **oxidation** occurs ( ext{Zn} ightarrow ext{Zn}^{2+} + 2e^-).\n * **Cathode:** Positive electrode where **reduction** occurs ( ext{Cu}^{2+} + 2e^- ightarrow ext{Cu}).\n * **Electromotive Force (EMF):** Voltage generated across the electrode double-layer when connected externally.\n * **Accumulator (Secondary Cell):** Reversible galvanic cell. Recharging forces non-spontaneous electrolysis to reverse the chemical chemical changes occurred during discharge.\n\n* **Electrolysis:**\n * Non-spontaneous electrochemical process driven by an external direct current (DC) power source passed through an electrolyte solution or melt.\n * **Anode:** Positive electrode connected to DC positive terminal; **oxidation** occurs (2 ext{Cl}^- ightarrow ext{Cl}{2(g)} + 2e^-).\n * **Cathode:** Negative electrode connected to DC negative terminal; **reduction** occurs (2 ext{Na}^+ + 2e^- ightarrow 2 ext{Na}_{(l)}).\n * **Faraday's First Law of Electrolysis:** The mass m$of a substance liberated at an electrode is directly proportional to the total electric charge$Q passed through the cell:\n

$m = A \times Q = A \times I \times t$

\n * **Faraday's Second Law of Electrolysis:** The mass of different elements liberated by the same electric charge is proportional to their chemical equivalents:\n

$m = \frac{M \times Q}{z \times F}$

\n * where M$is molar mass,$z$is electron stoichiometry per mole, and$F = 96485 ext{ C }mol^{-1} is Faraday's constant.\n\n\n# Inorganic Nomenclature and Stoichiometry Calculations\n\n* **Types of Chemical Formulas:**\n * **Empirical/Stoichiometric Formula:** Shows the simplest integer ratio of atoms present in the compound (e.g., ext{HO} for hydrogen peroxide).\n * **Molecular (Summative) Formula:** Shows the actual total number of each type of atom in a single molecule (e.g., ext{H}_2 ext{O}_2).\n * **Functional (Rational) Formula:** Emphasizes characteristic functional groups present (e.g., ext{NH}_4 ext{NO}_2).\n * **Structural (Constitutional) Formula:** Displays the order and connectivity of atoms within the molecule (e.g., ext{H–O–O–H}).\n * **Electron Dot Formula:** Illustrates all valence electrons, non-bonding pairs, and bonding pairs as dots and dashes.\n * **Geometric (Configurational) Formula:** Displays 3D spatial geometry of bonds around central atoms.\n\n* **Oxidation Numbers and Czech Naming Suffixes:**\n * The formal hypothetical charge an atom would carry if all bonds were fully ionic.\n * Rules: Free elements equal 0$;$ ext{H} = + ext{I}$(except metal hydrides where$ ext{H} = - ext{I}$);$ ext{O} = - ext{II}$(except peroxides where$ ext{O} = - ext{I}$, and$ ext{OF}_2$where$ ext{O} = + ext{II}$);$ ext{F} = - ext{I}$; Alkali metals$= + ext{I}$; Alkaline earth metals$= + ext{II}.\n * **Systematic Suffixes:**\n * + ext{I}: -ný (cation), -nan (anion), -ná (acid)\n * + ext{II}: -natý, -natan, -natá\n * + ext{III}: -itý, -itan, -itá\n * + ext{IV}: -ičitý, -ičitan, -ičitá\n * + ext{V}: -ičný / -ečný, -ičnan / -ečnan, -ičná / -ečná\n * + ext{VI}: -ový, -an, -ová\n * + ext{VII}: -istý, -istan, -istá\n * + ext{VIII}: -ičelý, -ičelan, -ičelá\n\n* **Quantitative Chemical Calculations:**\n * **Mass Fraction (w_A$):** Ratio of mass of component$A$to total mixture mass$m:\n

$w_A = \frac{m_A}{m}$

\n * **Volume Fraction (φ_A$):** Ratio of volume of component$A$to total volume$V:\n

$φ_A = \frac{V_A}{V}$

\n * **Molar Concentration (c_A$):** Moles of solute$n_A$divided by total solution volume$V\n

$c_A = \frac{n_A}{V} = \frac{m_A}{M_A \times V}$

\n * **Dilution / Mixing Equation:**\n

$m_1 \times w_1 + m_2 \times w_2 = (m_1 + m_2) \times w_3$

\n

$V_1 \times c_1 + V_2 \times c_2 = (V_1 + V_2) \times c_3$

\n\n\n# Systematic Inorganic Chemistry: Non-Metals and Main Group Elements\n\n* **Hydrogen and Noble Gases:**\n * **Noble Gases (Group 18):** Helium, Neon, Argon, Krypton, Xenon, Radon. Monoatomic, unreactive gases with filled valence octets (ns^2 np^6).\n * **Hydrogen ( ext{H}$):**$1s^1$. Three isotopes: Protium ($^1 ext{H}$), Deuterium ($^2 ext{H}$or$ ext{D}$), Tritium ($^3 ext{H}$or$ ext{T}, radioactive).\n * Laboratory preparation: Reaction of non-precious metals with acids: ext{Zn} + 2 ext{HCl} ightarrow ext{ZnCl}2 + ext{H}{2(g)}.\n * Industrial production: Reforming methane with steam: ext{CH}_4 + ext{H}_2 ext{O} ightarrow ext{CO} + 3 ext{H}_2$; or gasification of coke:$ ext{C} + ext{H}_2 ext{O} ightarrow ext{CO} + ext{H}_2\n\n* **Group 17 - Halogens (\text{F, Cl, Br, I, At}):**\n * Valence configuration ns^2 np^5$. Highly electronegative, diatomic molecules ($ ext{X}_2).\n * **Fluorine ( ext{F}_2$):** Yellow-green gas. Highest electronegativity ($4.1$). Exists only in oxidation state$- ext{I}$. Found in Kazivec (Fluorite,$ ext{CaF}_2$) and Cryolite ($ ext{Na}_3 ext{AlF}_6).\n * **Chlorine ( ext{Cl}_2$):** Yellow-green poisonous gas. Found in Halite ($ ext{NaCl}$), Sylvite ($ ext{KCl}$), and Carnallite ($ ext{KCl} imes ext{MgCl}_2 imes 6 ext{H}_2 ext{O}).\n * **Bromine ( ext{Br}_2):** Red-brown volatile liquid.\n * **Iodine ( ext{I}_2$):** Violet-black solid that readily sublimates. Dissolves poorly in water, but readily in$ ext{KI}$solution forming Lugol's solution ($ ext{I}_3^-).\n * **Halides:** Classified as ionic (high melting points, conductive in melts), polymeric/chain-like (e.g., ext{CoCl}_2$), or molecular (volatile covalent non-metal halides, e.g.,$ ext{PCl}_5).\n * **Chlorine Oxoacids:** Strength increases while oxidizing power decreases in the series: Hypochlorous acid ( ext{HClO}$, weak, strong bleach)$ ightarrow$Chlorous acid ($ ext{HClO}_2$)$ ightarrow$Chloric acid ($ ext{HClO}_3$)$ ightarrow$Perchloric acid ($ ext{HClO}_4, extremely strong acid).\n * Bleaching Louh: Mixture of ext{NaCl}$and$ ext{NaClO}.\n * Chlorine Lime: Mixture of ext{CaCl}_2$and$ ext{Ca(ClO)}_2.\n\n* **Group 16 - Chalcogens (\text{O, S, Se, Te, Po}):**\n * Valence configuration ns^2 np^4$. Can expand valency up to 6 using vacant$d-orbitals (except oxygen).\n * **Sulfur ( ext{S}):** Mined via the Frasch process using superheated steam. Used for rubber vulcanization (cross-linking polyisoprene chains via sulfur bridges to make rubber) and sulfuric acid production.\n * **Hydrogen Sulfide / Sulfan ( ext{H}_2 ext{S}$):** Colorless, toxic gas smelling of rotten eggs. Weak diprotic acid forming two salt series: Sulfides ($ ext{S}^{2-}$) and Hydrogensulfides ($ ext{HS}^-$). Roasting metal sulfides produces metal oxides and sulfur dioxide ($2 ext{ZnS} + 3 ext{O}_2 ightarrow 2 ext{ZnO} + 2 ext{SO}_2).\n * **Sulfur Dioxide ( ext{SO}_2$) and Trioxide ($ ext{SO}_3$):** Gas emissions causing acid rain. Oxidation of$ ext{SO}_2$to$ ext{SO}_3$over$ ext{V}_2 ext{O}_5 yields sulfuric acid.\n * **Sulfuric Acid ( ext{H}_2 ext{SO}_4$):** Strong diprotic acid, dense oily liquid, highly hygroscopic dehydrating agent. Oleum is a solution of$ ext{SO}_3$in concentrated$ ext{H}_2 ext{SO}_4$forming disulfuric acid ($ ext{H}_2 ext{S}_2 ext{O}_7).\n\n* **Group 15 - Nitrogen Group (\text{N, P, As, Sb, Bi}):**\n * Valence configuration ns^2 np^3.\n * **Nitrogen ( ext{N}_2$):** Colorless, inert gas due to a very strong triple bond ($ ext{N}≡ ext{N}$). Produced by fractional distillation of liquid air ($ ext{b.p. } -195.8 ext{ }^∘ ext{C}$vs oxygen at$-182 ext{ }^∘ ext{C}).\n * **Ammonia ( ext{NH}_3):** Pungent gas with strong hydrogen bonding. Produced industrially by the **Haber-Bosch Process**:\n

$\text{N}_{2(g)} + 3\text{H}_{2(g)} \rightleftharpoons 2\text{NH}_{3(g)} \text{ ​ ​ ​ ​ } (\text{Fe catalyst, } 450\text{ }^∘\text{C}, 20\text{ MPa})$

\n * **Nitric Acid ( ext{HNO}3$):** Strong acid and powerful oxidizer. Pure acid is colorless, but turns yellow under light due to decomposition into$ ext{NO}_2$. Passive metals ($ ext{Fe, Cr, Al}$) form protective oxide layers in concentrated$ ext{HNO}_3$. **Aqua Regia** is a 1:3 volume mixture of concentrated$ ext{HNO}_3$and$ ext{HCl}, capable of dissolving gold and platinum.\n * Industrial production sequence: 1. ext{ } 4 ext{NH}_3 + 5 ext{O}_2 ightarrow 4 ext{NO} + 6 ext{H}_2 ext{O}$;$2. ext{ } 2 ext{NO} + ext{O}_2 ightarrow 2 ext{NO}_2$;$3. ext{ } 3 ext{NO}_2 + ext{H}_2 ext{O} ightarrow 2 ext{HNO}_3 + ext{NO}.\n * **Phosphorus ( ext{P}$):** Exists as White phosphorus ($ ext{P}_4, soft, highly toxic, self-igniting in air), Red phosphorus (polymeric, non-toxic, stable), and Black phosphorus (crystalline, conductive layer structure).\n * Phosphoric Acid ( ext{H}_3 ext{PO}_4$): Medium-strong triprotic acid forming three salt series ($ ext{H}_2 ext{PO}_4^-$,$ ext{HPO}_4^{2-}$,$ ext{PO}_4^{3-}). Used to manufacture superphosphate fertilizers.\n\n* **Group 14 - Carbon Group (\text{C, Si, Ge, Sn, Pb}):**\n * Valence configuration ns^2 np^2.\n * **Carbon ( ext{C}$):** Allotropes include **graphite** (hexagonal layers of$sp^2$carbons, soft, electrically conductive), **diamond** (3D tetrahedral network of$sp^3 carbons, extremely hard), **fullerenes**, **active carbon** (porous, high surface area for adsorption), and **soot**.\n * Carbon Monoxide ( ext{CO}$): Colorless, odorless, toxic gas binding irreversibly to hemoglobin. Strong reducing agent. Component of **water gas** ($ ext{H}_2 + ext{CO}$) and **generator gas** ($ ext{N}_2 + ext{CO}).\n * Carbon Dioxide ( ext{CO}_2): Linear nonpolar gas, product of complete combustion. Solid state is known as **dry ice**.\n * Carbon disulfide ( ext{CS}_2$), Hydrogen cyanide ($ ext{HCN}$), Potassium cyanide ($ ext{KCN}, cyankali).\n * **Silicon ( ext{Si}$):** Semiconductor with a diamond-like lattice. Resistive to acids except$ ext{HF}$. Mined as silica ($ ext{SiO}_2, quartz, rock crystal, amethyst, agate, opal).\n * Silanes: Silicon hydrides ( ext{Si}_n ext{H}{2n+2}), highly reactive and pyrophoric.\n * Silicones: Polymeric organosilicon compounds containing repeated ext{[–Si(R)}_2 ext{–O–]} units. Highly hydrophobic and heat-resistant.\n * **Tin (\text{Sn}$) and Lead ($\text{Pb}$):** Mined as Cassiterite ($ ext{SnO}_2$) and Galena ($ ext{PbS}$). Tin forms thin foils (**staniol**); cold temperatures cause structural transformation to gray tin powder (**tin pest**). Lead compounds are toxic; Minium / Red Lead ($ ext{Pb}_3 ext{O}_4) is used in anti-corrosive paints.\n\n* **Group 13 - Boron Group (\text{B, Al, Ga, In, Tl}):**\n * Valence configuration ns^2 np^1.\n * **Boron ( ext{B}$):** Metalloid forming electron-deficient bonds. Boric acid ($ ext{H}_3 ext{BO}_3$), Borax ($ ext{Na}_2 ext{B}_4 ext{O}_7 imes 10 ext{H}_2 ext{O}).\n * **Aluminum ( ext{Al}$):** Low-density, ductile metal protected by passive oxide film. Mined as Bauxite ($ ext{Al}_2 ext{O}_3 imes x ext{H}_2 ext{O}$) and Corundum ($ ext{Al}_2 ext{O}_3$). Amphoteric hydroxide$ ext{Al(OH)}_3 dissolves in both acids and strong bases:\n

$\text{Al(OH)}_3 + 3\text{H}^+ \rightarrow \text{Al}^{3+} + 3\text{H}_2\text{O}$

\n

$\text{Al(OH)}_3 + \text{OH}^- \rightarrow [\text{Al(OH)}_4]^- \text{ (tetrahydroxoaluminate)}$

\n * **Aluminothermy:** Reduction of metal oxides using powdered aluminum at high temperatures ( ext{Fe}_2 ext{O}_3 + 2 ext{Al} ightarrow 2 ext{Fe} + ext{Al}_2 ext{O}_3).\n\n\n# Main Group Metals and Transition Metals\n\n* **Group 1 - Alkali Metals (\text{Li, Na, K, Rb, Cs, Fr}):**\n * Valence configuration ns^1. Soft, silver-white, low-density metals stored under inert liquids (petroleum). Highly reactive reducers with low electronegativity.\n * Flame Test Colors: Lithium = carmine red; Sodium = intense yellow; Potassium = light violet.\n * Reactions with Oxygen: Lithium forms oxide ( ext{Li}_2 ext{O}$); Sodium forms peroxide ($ ext{Na}_2 ext{O}_2$); Potassium, Rubidium, and Cesium form superoxides ($ ext{MO}_2).\n * Solvay Process for Sodium Carbonate ( ext{Na}_2 ext{CO}_3 / Soda):\n

$\text{NaCl} + \text{NH}_3 + \text{CO}_2 + \text{H}_2\text{O} \rightarrow \text{NaHCO}_{3(s)} ↓ + \text{NH}_4\text{Cl}$

\n

$2\text{NaHCO}_3 \rightarrow \text{Na}_2\text{CO}_3 + \text{CO}_{2(g)} + \text{H}_2\text{O}$

\n\n* **Group 2 - Alkaline Earth Metals (\text{Be, Mg, Ca, Sr, Ba, Ra}):**\n * Valence configuration ns^2$. Always form$+ ext{II} oxidation state. Calcium, Strontium, Barium, and Radium are true alkaline earth metals.\n * **Water Hardness:**\n * *Temporary Hardness:* Caused by dissolved calcium and magnesium hydrogen carbonates ( ext{Ca(HCO}_3)_2). Removed by boiling:\n

$\text{Ca(HCO}_3)_2 \rightarrow \text{CaCO}_{3(s)} ↓ + \text{CO}_{2(g)} + \text{H}_2\text{O}$

\n * *Permanent Hardness:* Caused mainly by sulfates ( ext{CaSO}4$,$ ext{MgSO}_4$) and chlorides. Removed by chemical precipitation with soda ($ ext{Na}_2 ext{CO}_3).\n * **Calcium Compounds:** Quicklime ( ext{CaO}$), Slaked lime ($ ext{Ca(OH)}_2$), Limestone ($ ext{CaCO}_3$), Gypsum ($ ext{CaSO}_4 imes 2 ext{H}_2 ext{O}$), Plaster of Paris ($ ext{CaSO}_4 imes 0.5 ext{H}_2 ext{O}).\n\n* **Transition Metals (d-Block Elements):**\n * Elements in Groups 3 to 12. Characterized by partially filled (n-1)d subshells. Exhibit multiple oxidation states, formation of colored ions, paramagnetic behavior, and strong coordination complex chemistry.\n * **Iron Triad (\text{Fe, Co, Ni}):**\n * **Iron ( ext{Fe}$):**$[ ext{Ar}] 3d^6 4s^2$. Ferromagnetic. Mined as Hematite ($ ext{Fe}_2 ext{O}_3$), Magnetite ($ ext{Fe}_3 ext{O}_4$), Siderite ($ ext{FeCO}_3$), Pyrite ($ ext{FeS}_2$), Limonite. Quickly corrodes in moist air forming rust ($ ext{Fe}_2 ext{O}_3 imes x ext{H}_2 ext{O}).\n * **Blast Furnace Iron Production:**\n * Direct Reduction: ext{Fe}_2 ext{O}_3 + 3 ext{C} ightarrow 2 ext{Fe} + 3 ext{CO}\n * Indirect Reduction: 3 ext{Fe}_2 ext{O}_3 + ext{CO} ightarrow 2 ext{Fe}_3 ext{O}_4 + ext{CO}_2$;$ ext{Fe}_3 ext{O}_4 + ext{CO} ightarrow 3 ext{FeO} + ext{CO}_2$;$ ext{FeO} + ext{CO} ightarrow ext{Fe} + ext{CO}_2\n * **Pig Iron / Cast Iron:** High carbon content (> 21.4 ext{‰}), hard, brittle, non-malleable. Refined into **steel** by lowering carbon content. Heat treatments include **quenching** (kalení: rapid cooling yields hard, brittle steel) and **tempering** (popouštění: slow reheating restores elasticity).\n * Mohr's Salt: (NH_4)_2Fe(SO_4)_2 imes 6H_2O.\n * **Group 12 (\text{Zn, Cd, Hg}):**\n * **Zinc ( ext{Zn}$):** Used in galvanizing steel and alloys (Brass =$ ext{Cu} + ext{Zn}$). Zinc White ($ ext{ZnO}$), White Vitriol ($ ext{ZnSO}_4 imes 7 ext{H}_2 ext{O}).\n * **Mercury ( ext{Hg}$):** Heavy liquid metal. Forms **amalgams** (alloys with metals like$ ext{Ag, Au, Cu}$). Mined as Cinnabar ($ ext{HgS}$). Calomel ($ ext{Hg}_2 ext{Cl}_2) used in electrochemistry.\n * **Group 11 (\text{Cu, Ag, Au}$):** Bronze =$ ext{Cu} + ext{Sn}$. Chalcopyrite ($ ext{CuFeS}_2$), Blue Vitriol ($ ext{CuSO}_4 imes 5 ext{H}_2 ext{O}).\n * **Group 6 & 7 (\text{Cr, Mn}$):** Potassium permanganate ($ ext{KMnO}_4$) is a powerful lab oxidizer. Chromates ($ ext{CrO}_4^{2-}$, yellow) interconvert with dichromates ($ ext{Cr}_2 ext{O}_7^{2-}, orange) in acidic media.\n\n\n# Fundamental Concepts of Organic Chemistry\n\n* **General Properties of Organic Compounds:**\n * Predominantly covalent bonding, lower melting and boiling points than inorganic salts, heat-sensitive/thermolabile, non-conductive, frequently flammable, soluble mainly in nonpolar organic solvents.\n * **Butlerov's Structural Theory:** The chemical and physical properties of organic molecules are dictated not only by their elemental composition, but specifically by their chemical constitution and structural arrangement.\n\n* **Types of Isomerism:**\n * **Constitutional Isomers:** Same molecular formula, but different atom connectivity.\n * *Chain Isomerism:* Differences in the carbon backbone arrangement (e.g., butane vs. isobutane).\n * *Positional Isomerism:* Differences in the location of a substituent or double/triple bond (e.g., propan-1-ol vs. propan-2-ol).\n * *Functional Isomerism:* Differences in functional group type (e.g., ethanol ext{CH}_3 ext{CH}_2 ext{OH}$vs. dimethyl ether$ ext{CH}_3 ext{–O–CH}_3).\n * **Configurational Isomers (Stereoisomers):** Same constitutional connectivity, but different 3D spatial arrangement.\n * **Geometrical (E)/(Z)$or *cis*/*trans* Isomers:** Restricted rotation around double bonds or ring systems. Priority 1-4 assigned by atomic mass.$(Z)$= highest priority substituents on same side (*zusammen*);$(E) = opposite sides (*entgegen*).\n * **Enantiomers (Optical Isomers):** Non-superimposable mirror images. Requires a **chiral center** (an asymmetric carbon atom bonded to 4 different substituents). Enantiomers rotate the plane of polarized light by equal angles in opposite directions: dextrorotatory (+$, right) and levorotatory ($- , left). Named **D-** or **L-** based on structural orientation relative to L-glyceraldehyde.\n * **Racemic Mixture:** A 1:1 equimolar mixture of two enantiomers; optically inactive due to internal cancellation.\n * **Conformational Isomers:** Different spatial arrangements generated by free internal rotation around single ext{C–C} bonds (e.g., eclipsed vs. staggered conformations of ethane; chair vs. boat conformations of cyclohexane).\n\n* **Primary Organic Raw Materials:**\n * **Petroleum:** Complex mixture of alkanes, cycloalkanes, and arenes. Refined via **fractional distillation** into:\n * *Hydrocarbon Gases:* Propane, butane.\n * *Gasoline Fraction:* Fuel for spark-ignition engines ( ext{b.p. } 40 ext{--}200 ext{ }^∘ ext{C}). Quality measured by **Octane Number** (anti-knock property rating relative to isooctane = 100 vs. n-heptane = 0).\n * *Kerosene Fraction:* Jet turbine fuel, heating solvent.\n * *Gas Oil (Diesel):* Fuel for diesel engines.\n * *Mazut / Residuals:* Vacuum distilled into heavy lubricating oils, paraffin, and asphalt.\n * *Cracking:* Thermal or catalytic cleavage of long-chain hydrocarbons into short-chain alkenes (ethylene, propylene) and gasoline.\n * **Natural Gas:** Composed primarily of **methane ( ext{CH}_4$)**, alongside ethane, propane, butane,$ ext{CO}_2$, and$ ext{N}_2.\n * **Coal:** High-molecular-weight solid carbonaceous rock. Processed via **destructive distillation (carbonization)** at 900 ext{ }^∘ ext{C} without oxygen, yielding **coke** (solid reducer), **coal tar** (aromatic compounds like naphthalene), and **coal gas / town gas**.\n\n\n# Hydrocarbons: Classes, Reactions, and Derivatives\n\n* **Alkanes ( ext{C}_n ext{H}{2n+2}):**\n * Saturated open-chain hydrocarbons with single ext{C–C}$$ ext{σ}$bonds ($sp^3 hybridized carbons).\n * Nonpolar, water-insoluble. React via **Free Radical Substitution (S_R)**.\n * *Halogenation Mechanism:* 1. ext{ Initiation: } ext{Cl}2 ightarrow 2 ext{Cl}^•$(UV light);$2. ext{ Propagation: } ext{CH}_4 + ext{Cl}^• ightarrow ext{CH}_3^• + ext{HCl}$;$ ext{CH}_3^• + ext{Cl}_2 ightarrow ext{CH}_3 ext{Cl} + ext{Cl}^•$;$3. ext{ Termination: } 2 ext{Cl}^• ightarrow ext{Cl}_2.\n\n* **Alkenes ( ext{C}_n ext{H}{2n}) and Alkadienes:**\n * Unsaturated hydrocarbons containing one double bond (sp^2$hybridized, one$ ext{σ}$and one$ ext{χ} bond).\n * React via **Electrophilic Addition (A_E)** across the double bond.\n * **Markovnikov's Rule:** In the addition of an unsymmetrical protic acid ( ext{H–X}) to an unsymmetrical alkene, the hydrogen atom adds to the double-bonded carbon carrying the greater number of hydrogen atoms, while the halogen/nucleophile adds to the more substituted carbon.\n * *Alkadienes:* Contain two double bonds. Types: Isolated ( ext{CH}2 ext{=CH–CH}_2 ext{–CH=CH}_2$), Conjugated ($ ext{CH}_2 ext{=CH–CH=CH}_2$, 1,3-butadiene), or Cumulated ($ ext{CH}_2 ext{=C=CH}_2). Conjugated dienes readily undergo polymerization to yield synthetic rubbers.\n\n* **Alkynes ( ext{C}_n ext{H}{2n-2}):**\n * Unsaturated hydrocarbons containing one triple bond (sp$hybridized, one$ ext{σ}$and two$ ext{χ} bonds).\n * **Ethyne (Acetylene, ext{HC}≡ ext{CH}):** Colorless gas used in oxy-acetylene welding torches.\n * Addition of water to ethyne (catalyzed by ext{Hg}^{2+}/ ext{H}2 ext{SO}_4) yields vinyl alcohol intermediate, which rapidly rearranges to stable **acetaldehyde** via **Keto-Enol Tautomerism**.\n * Terminal hydrogen atoms on alkynes are weakly acidic and can be displaced by heavy metal ions to form explosive **acetylides** (e.g., Calcium carbide/acetylide ext{CaC}_2).\n\n* **Arenes (Aromatic Hydrocarbons):**\n * Planar cyclic systems containing delocalized ext{χ}$electrons ($4n + 2$$ ext{χ} electrons according to Hückel's rule).\n * Highly stable due to **delocalization energy**. React primarily via **Electrophilic Aromatic Substitution (S_E)** rather than addition.\n * **Electrophilic Substitution Reactions on Benzene:**\n * *Nitration:* Reaction with ext{HNO}_3 / ext{H}_2 ext{SO}_4$producing **nitrobenzene** (electrophile$ ext{NO}_2^+).\n * *Halogenation:* Reaction with ext{Cl}_2 / ext{FeCl}_3$producing **chlorobenzene** (electrophile$ ext{Cl}^+).\n * *Sulfonation:* Reaction with ext{H}_2 ext{SO}_4 / ext{SO}_3 producing **benzenesulfonic acid**.\n * *Friedel-Crafts Alkylation:* Reaction with ext{R–Cl} / ext{AlCl}_3 introducing an alkyl group.\n * **Directing Effects of Substituents:**\n * **Activating / 1st Class Substituents:** Electron-donating groups (- ext{OH, –NH}_2 ext{, –R, halogens}$) direct incoming electrophiles to **ortho-** ($1,2$) and **para-** ($1,4) positions.\n * **Deactivating / 2nd Class Substituents:** Electron-withdrawing groups (- ext{NO}_2 ext{, –COOH, –CHO, –SO}_3 ext{H}$) direct incoming electrophiles to the **meta-** ($1,3) position.\n * **Key Aromatic Compounds:** Benzene (carcinogenic solvent), Toluene (methylbenzene, inhaled toxicant, oxidized to benzoic acid), Xylenes (o-, m-, p- dimethylbenzenes), Styrene (vinylbenzene, monomer for polystyrene), Naphthalene (sublimating solid).\n\n* **Halogen Derivatives:**\n * Hydrocarbons where one or more hydrogens are replaced by halogen atoms ( ext{F, Cl, Br, I}).\n * Highly reactive via **Nucleophilic Substitution (S_N$)** and **Elimination ($E)**.\n * Trichloromethane (Chloroform, ext{CHCl}_3$), Tetrachloromethane ($ ext{CCl}_4$), Tetrafluoroethylene ($ ext{CF}_2 ext{=CF}_2), Freons (chlorofluorocarbons destroying ozone layer).\n\n* **Nitro and Amino Derivatives:**\n * **Nitro Derivatives:** Contain single-bonded nitro groups (- ext{NO}_2$). Reduction of nitrobenzene using iron and$ ext{HCl} yields **aniline** (aminobenzene).\n * **Amines:** Organic derivatives of ammonia classified as primary ( ext{R–NH}_2$), secondary ($ ext{R}_2 ext{NH}$), or tertiary ($ ext{R}_3 ext{N}$). Basic in character due to the lone pair on nitrogen. React with nitrous acid ($ ext{HNO}_2) at low temperatures to undergo **diazotization**, forming **diazonium salts**, which couple with phenols/amines to synthesize **azo dyes**.\n\n* **Organometallic Compounds:**\n * Contain direct ext{C–Metal}$bonds. **Grignard Reagents** ($ ext{R–Mg–X}) are versatile synthetic intermediates prepared in dry ether.\n\n\n# Oxygen-Containing and Carboxylic Acid Derivatives\n\n* **Alcohols and Phenols:**\n * Contain one or more hydroxyl groups (- ext{OH}$). Alcohols are bound to aliphatic carbons; phenols have$-OH directly attached to an aromatic ring.\n * **Physical Properties:** High boiling points and water solubility due to extensive intermolecular hydrogen bonding.\n * **Chemical Behavior:** Weakly amphoteric.\n * Alcohols react with active alkali metals to form **alkoxides / alcoholates** (2 ext{R–OH} + 2 ext{Na} ightarrow 2 ext{R–ONa} + ext{H}_2).\n * Phenols are substantially more acidic than alcohols due to resonance stabilization of the phenoxide anion, reacting readily with aqueous ext{NaOH} to form **phenoxides**.\n * **Oxidation Reactions:**\n * *Primary Alcohols:* Oxidized first to **aldehydes**, then further to **carboxylic acids** ( ext{R–CH}_2 ext{OH} ightarrow ext{R–CHO} ightarrow ext{R–COOH}).\n * *Secondary Alcohols:* Oxidized strictly to **ketones** ( ext{R}_2 ext{CH–OH} ightarrow ext{R}_2 ext{C=O}).\n * *Tertiary Alcohols:* Resistant to oxidation without breaking the carbon backbone.\n * **Important Representatives:** Methanol ( ext{CH}_3 ext{OH}$, toxic, causes blindness/death), Ethanol ($ ext{CH}_3 ext{CH}_2 ext{OH}, beverage alcohol, produced by yeast fermentation of glucose), Ethane-1,2-diol (Ethylene glycol, toxic antifreeze component), Propane-1,2,3-triol (Glycerol, constituent of lipids), Phenol (corrosive disinfectant, precursor to Bakelite and picric acid / 2,4,6-trinitrophenol).\n\n* **Ethers:**\n * Compounds of general structure ext{R–O–R'}$. Volatile, highly flammable liquids with pleasant odor. Form explosive peroxides upon exposure to light and atmospheric oxygen. Excellent nonpolar laboratory solvents (e.g., Diethyl ether$ ext{CH}_3 ext{CH}_2 ext{–O–CH}_2 ext{CH}_3).\n\n* **Carbonyl Compounds (Aldehydes and Ketones):**\n * Contain a polar carbonyl double bond ( ext{C=O}$) with a partial positive charge on carbon ($δ^+$) and a partial negative charge on oxygen ($δ^-).\n * React via **Nucleophilic Addition (A_N)**.\n * **Aldehydes ( ext{R–CHO}):** Carbonyl group located at the terminus of the chain. Easily oxidized to carboxylic acids; act as strong reducing agents (reduce Fehling's and Tollens' silver mirror reagents).\n * *Formaldehyde (Methanal, ext{HCHO}$):* Pungent gas. Its 40$ ext{CH}_3 ext{CHO}):* Volatile liquid produced by oxidation of ethanol. Polymers form metaldehyde (solid fuel).\n * *Benzaldehyde:* Liquid with bitter almond odor.\n * **Ketones ( ext{R–CO–R'}):** Carbonyl group flanked by two carbon residues. Resistant to mild oxidation.\n * *Acetone (Propanone, ext{CH}_3 ext{COCH}_3):* Flammable toxic solvent. Formed in small amounts in human lipid metabolism during starvation or diabetes.\n * **Iodoform Reaction:** Reaction of ethanol or acetaldehyde with ext{I}_2/ ext{NaOH}$forming yellow crystalline iodoform ($ ext{CHI}_3).\n\n* **Carboxylic Acids:**\n * Contain a carboxyl group (- ext{COOH}), combining a carbonyl and hydroxyl group. Form stable hydrogen-bonded dimers in liquid state.\n * Weak acids that dissociate in water to form carboxylate anions ( ext{R–COO}^-), where negative charge is symmetrically delocalized across both oxygen atoms.\n * **Monocarboxylic Acids:** Formic acid ( ext{HCOOH}$, pungent, strongest unsubstituted aliphatic acid), Acetic acid ($ ext{CH}_3 ext{COOH}$, glacial acetic acid freezes at$16.6 ext{ }^∘ ext{C}$), Propionic, Butyric, Palmitic ($ ext{C}{15} ext{H}{31} ext{COOH}$), Stearic ($ ext{C}{17} ext{H}{35} ext{COOH}$), Oleic ($ ext{C}{17} ext{H}{33} ext{COOH}).\n * **Dicarboxylic Acids:** Oxalic acid ( ext{HOOC–COOH}), Malonic, Succinic, Glutaric, Adipic, Maleic acid (*cis*-butenedioic), Fumaric acid (*trans*-butenedioic), Phthalic, Terephthalic acid.\n * **Functional Derivatives of Carboxylic Acids:**\n * *Salts ( ext{R–COOM}):* Formed by neutralization. Alkaline salts of fatty acids are **soaps**.\n * *Acyl Halides ( ext{R–COX}):* Highly reactive acylating agents.\n * *Anhydrides ( ext{(RCO)}_2 ext{O}):* Formed by dehydration of two carboxyl groups.\n * *Esters ( ext{R–COOR'}):* Formed via **Esterification** (acid-catalyzed reaction of a carboxylic acid with an alcohol releasing water). Volatile compounds with fruity scents.\n * *Amides ( ext{R–CONH}_2$):* Derived by replacing$-OH$with$-NH_2. Prepared by heating ammonium carboxylates.\n * *Nitriles ( ext{R–C}≡ ext{N}$):* Prepared by dehydration of amides (e.g., Acrylonitrile$ ext{CH}_2 ext{=CH–CN}).\n * **Substitutional Derivatives of Carboxylic Acids:**\n * *Halogen Acids:* Hydrogen on carbon chain replaced by halogen; increases acid strength (e.g., Trichloroacetic acid).\n * *Hydroxy Acids:* Contain -OH$and$-COOH. Lactic acid (2-hydroxypropanoic acid, forms in active muscles and sour milk), Malic acid, Tartaric acid, Citric acid (2-hydroxypropane-1,2,3-tricarboxylic acid), Salicylic acid (2-hydroxybenzoic acid; acetylated with acetic anhydride to produce **Aspirin / Acylpyrin**).\n * *Keto Acids:* Contain -CO-$and$-COOH$. Pyruvic acid ($ ext{CH}_3 ext{COCOOH}$, end product of glycolysis), Acetoacetic acid, Oxaloacetic acid,$α-Ketoglutaric acid.\n\n\n# Synthetic Polymers and Heterocyclic Compounds\n\n* **Heterocyclic Compounds:**\n * Cyclic organic compounds containing one or more atoms other than carbon (heteroatoms: ext{N, O, S}) within the ring network.\n * **Five-Membered Rings with One Heteroatom:** Furan (contains ext{O}$), Thiophene (contains$ ext{S}$), Pyrrole (contains$ ext{N}, basic structural component of porphyrins, heme, and chlorophyll).\n * **Five-Membered Rings with Two Heteroatoms:** Pyrazole (contains 2 ext{N}$), Imidazole (contains 2$ ext{N}, present in histidine).\n * **Six-Membered Rings:** Pyridine (contains 1 ext{N}$, weak base present in$ ext{NAD}^+$and nicotinamide), Pyrimidine (contains 2$ ext{N} in 1,3-positions, parent structure of cytosine, uracil, and thymine).\n * **Bicyclic Heterocycles:** Indole (benzene + pyrrole), Purine (imidazole + pyrimidine, parent structure of adenine, guanine, uric acid, and caffeine).\n\n* **Synthetic Macromolecular Substances:**\n * High-molecular-weight substances (M_r > 10000$) composed of repeating structural units called **mers** linked together in long chains. The number of mers in a polymer chain is the **degree of polymerization ($n)**.\n * **Classification of Plastics:**\n * *Thermoplastics:* Soften upon heating, become plastic, and can be repeatedly reshaped (e.g., Polyethylene, Polypropylene, PVC).\n * *Thermosets:* Irreversibly harden and cross-link upon heating; cannot be remelted without chemical degradation (e.g., Aminoplasts, Phenoplasts/Bakelite).\n * *Elastomers:* Highly elastic materials that can be stretched multiple times their original length and instantly recover their original shape (e.g., Synthetic Rubbers).\n * **Polyreactions:**\n * **Polymerization:** Chain reaction where unsaturated monomers containing double bonds link together without producing any low-molecular-weight by-products (n ext{ CH}_2 ext{=CH}_2 ightarrow ext{[–CH}_2 ext{–CH}_2 ext{–]}_n).\n * *Polyethylene (PE), Polypropylene (PP), Polyvinyl chloride (PVC), Polytetrafluoroethylene (PTFE/Teflon), Polystyrene (PS).*\n * **Polycondensation:** Step-growth reaction between bifunctional monomers carrying reactive functional groups, releasing a low-molecular-weight by-product (such as ext{H}_2 ext{O}$or$ ext{NH}_3).\n * *Polyamides (Nylon 6,6), Polyesters (PET).* \n * **Polyaddition:** Reaction between polyfunctional monomers involving hydrogen atom migration without forming low-molecular-weight by-products (e.g., formation of Polyurethanes from diisocyanates and diols).\n\n\n# Biochemistry: Amino Acids, Proteins, and Carbohydrates\n\n* **Biochemical Foundations:**\n * **Biogenic Elements:**\n * *Macroelements (> 1% body weight):* Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Calcium.\n * *Microelements (0.05% to 1%):* Sulfur, Potassium, Sodium, Magnesium, Chlorine.\n * *Trace Elements (< 0.05%):* Cobalt, Zinc, Manganese, Iodine, Iron.\n * **Biopolymers:** High-molecular biomolecules composed of repeating units (Proteins, Nucleic Acids, Polysaccharides).\n\n* **Amino Acids:**\n * Substitutional derivatives of carboxylic acids containing an amino group (- ext{NH}_2$) and a carboxyl group ($- ext{COOH}$). All natural proteinogenic amino acids are **$α-\text{L}-amino acids** (except glycine, which is non-chiral).\n * 20 coded proteinogenic amino acids. **Essential Amino Acids** (must be acquired from food): Valine, Leucine, Isoleucine, Threonine, Lysine, Methionine, Phenylalanine, Tryptophan.\n * **Amphoteric Properties:** In aqueous solution, amino acids form dipolar ions (**Zwitterions**, ext{R–CH(NH}_3^+ ext{)COO}^-).\n * In acidic media (pH < pI$): Accepts$ ext{H}^+ ightarrow **Cation**.\n * In basic media (pH > pI$): Donates$ ext{H}^+ ightarrow **Anion**.\n * **Isoelectric Point (pI):** Specific pH at which the amino acid carries no net electrical charge and does not migrate in an electric field.\n\n* **Peptides and Proteins:**\n * **Peptide Bond:** Amide linkage formed by reaction of the α$-carboxyl group of one amino acid with the$α$-amino group of another, releasing water ($ ext{–CO–NH–}).\n * **Peptides:** Relative molecular mass M_r ≤ 10000. Peptides include peptide hormones (Oxytocin, Vasopressin, Insulin) and Glutathione.\n * **Proteins:** M_r > 10000.\n * **Protein Structural Levels:**\n * *Primary Structure:* Linear sequence of amino acids linked by covalent peptide bonds.\n * *Secondary Structure:* Local regular spatial folding of the polypeptide backbone stabilized by hydrogen bonds (α$-helix or$β-pleated sheet).\n * *Tertiary Structure:* Overall 3D spatial conformation of a single polypeptide chain, stabilized by disulfide bridges (Ȓ ext{S–S}‒), ionic interactions, hydrophobic interactions, and hydrogen bonds.\n * *Quaternary Structure:* Spatial arrangement of multiple individual polypeptide subunits into a functional oligomeric complex (e.g., Hemoglobin).\n * **Denaturation:** Disruption of higher-order protein structures (secondary, tertiary, quaternary) without breaking primary peptide bonds, caused by heat, heavy metals, strong acids/bases, or organic solvents. Leads to loss of biological activity.\n\n* **Carbohydrates:**\n * Polyhydroxyaldehydes (**Aldoses**) or polyhydroxyketones (**Ketoses**).\n * **Monosaccharides:** Cannot be hydrolyzed into simpler sugars.\n * *D-Glyceraldehyde* and *Dihydroxyacetone:* Simplest trioses.\n * *D-Glucose:* Aldohexose, primary cellular metabolic fuel.\n * *D-Fructose:* Ketohexose, sweetest sugar.\n * *D-Galactose:* Epimer of glucose at carbon 4.\n * *D-Ribose* and *2-Deoxy-D-Ribose:* Pentoses forming nucleic acid backbones.\n * **Cyclic Forms and Haworth Formulas:** Intramolecular reaction between the carbonyl group and a hydroxyl group forms cyclic hemiacetals (**Pyranoses** 6-membered, or **Furanoses** 5-membered). Creates a new chiral center at C1 called the **anomeric carbon**, producing **α$** and **$β anomers**.\n * **Oligosaccharides:** Contain 2 to 10 monosaccharide units joined by **glycosidic bonds**.\n * *Maltose:* Malt sugar (α ext{-D-glucose} + α ext{-D-glucose}$,$α-1,4 glycosidic bond). Reducing sugar.\n * *Lactose:* Milk sugar (β ext{-D-galactose} + α ext{-D-glucose}$,$β-1,4 glycosidic bond). Reducing sugar.\n * *Sucrose:* Cane/beet sugar (α ext{-D-glucose} + β ext{-D-fructose}$,$α, β-1,2 glycosidic bond). Non-reducing sugar.\n * **Polysaccharides:** High biopolymers (> 10 units).\n * *Starch:* Plant energy storage homopolymer of α ext{-D-glucose}$. Consists of **Amylose** (linear,$α-1,4$linkages) and **Amylopectin** (branched,$α-1,4$and$α-1,6 linkages).\n * *Glycogen:* Animal storage polysaccharide, highly branched α ext{-D-glucose} polymer.\n * *Cellulose:* Plant structural wall component, linear polymer of β ext{-D-glucose}$connected via$β-1,4 glycosidic bonds. Insoluble fiber.\n * *Chitin:* Fungal and arthropod structural polymer of N-acetyl-glucosamine.\n\n\n# Lipids, Isoprenoids, Alkaloids, and Nucleic Acids\n\n* **Lipids:**\n * Esters of fatty acids and alcohols. Water-insoluble, highly soluble in nonpolar organic solvents.\n * **Simple Lipids:**\n * **Fats and Oils (Triacylglycerols):** Triesters of glycerol and higher fatty acids. Saturated fatty acids yield solid fats; unsaturated fatty acids with double bonds yield liquid oils.\n * *Alkaline Hydrolysis (Saponification):* Heating fats with aqueous ext{NaOH}$or$ ext{KOH} splits them into glycerol and alkali salts of fatty acids (**Soaps**).\n * *Hardening of Fats:* Catalytic hydrogenation of unsaturated double bonds converting liquid oils into solid fats.\n * *Waxes:* Esters of long-chain fatty acids with long-chain monohydric aliphatic alcohols (e.g., spermaceti, beeswax).\n * **Complex Lipids:**\n * *Phospholipids:* Contain a glycerol backbone, two fatty acids, a phosphate group, and an alcohol base (e.g., choline in Lecithin). Possess **amphiphilic properties** (hydrophilic head, hydrophobic tails) forming biological cell membrane bilayers.\n * *Sphingolipids:* Contain sphingosine instead of glycerol.\n * *Glycolipids:* Contain carbohydrate moieties bound to lipids.\n\n* **Isoprenoids:**\n * Natural lipids built from 5-carbon **isoprene** units ( ext{CH}_2 ext{=C(CH}_3 ext{)–CH=CH}_2).\n * **Terpenes:** Classified by number of isoprene units: Monoterpenes (2 ext{ units / }10 ext{ C's}$: Menthol, Camphor, Limonene), Sesquiterpenes ($3 ext{ units / }15 ext{ C's}$), Diterpenes ($4 ext{ units / }20 ext{ C's}$: Phytol in chlorophyll), Triterpenes ($6 ext{ units / }30 ext{ C's}$: Squalene), Tetraterpenes ($8 ext{ units / }40 ext{ C's}$:$β-carotene, Lycopene), Polyterpenes (Natural rubber / cis-polyisoprene).\n * **Steroids:** Derived from the saturated tetracyclic hydrocarbon **cyclopentanoperhydrophenanthrene (Sterane)**.\n * *Sterols:* Cholesterol (essential membrane constituent, precursor of steroid hormones and bile acids), Ergosterol (precursor to Vitamin ext{D}_2).\n * *Bile Acids:* Cholic acid (emulsifies fats in digestive tract).\n * *Steroid Hormones:* Sex hormones (Testosterone, Estradiol, Progesterone) and Adrenal Cortex Hormones (Cortisol, Aldosterone).\n\n* **Alkaloids:**\n * Naturally occurring, basic, nitrogen-containing heterocyclic plant compounds with potent physiological and pharmacological effects.\n * *Opium Alkaloids:* Morphine (analgesic), Codeine, Heroin (diacetylmorphine).\n * *Tropane Alkaloids:* Atropine, Scopolamine, Cocaine.\n * *Other Notable Alkaloids:* Caffeine (purine derivative in coffee/tea), Nicotine (tobacco), Quinine (antimalarial), LSD (lysergic acid diethylamide).\n\n* **Nucleic Acids:**\n * High-molecular biopolymers storing and transmitting genetic information.\n * **Monomeric Unit (Nucleotide):** Consists of three components: Nitrogenous Heterocyclic Base + Pentose Sugar + Phosphate Group.\n * *Nucleoside:* Nitrogenous Base + Pentose Sugar.\n * **Nitrogenous Bases:**\n * *Purine Bases:* Adenine ( ext{A}$), Guanine ($ ext{G}).\n * *Pyrimidine Bases:* Cytosine ( ext{C}$), Thymine ($ ext{T}$, in DNA), Uracil ($ ext{U}, in RNA).\n * **DNA (Deoxyribonucleic Acid):** Sugar is 2-deoxy-D-ribose. Bases are ext{A, T, C, G}$. Structure is a **double-stranded right-handed antiparallel helix** held together by complementary base pairing via hydrogen bonds:$ ext{A=T}$(2 hydrogen bonds) and$ ext{G}≡ ext{C} (3 hydrogen bonds).\n * **RNA (Ribonucleic Acid):** Sugar is D-ribose. Bases are ext{A, U, C, G}. Single-stranded.\n * *Messenger RNA (m-RNA):* Carries copied genetic code from nuclear DNA to ribosomes.\n * *Transfer RNA (t-RNA):* Translates genetic code by transporting specific amino acids to ribosomes during protein synthesis; contains an **anticodon** loop.\n * *Ribosomal RNA (r-RNA):* Structural and catalytic component of ribosomes.\n\n\n# Vitamins, Enzymes, and Metabolic Pathways\n\n* **Vitamins:**\n * Essential low-molecular-weight organic compounds that human organisms cannot synthesize and must ingest in food. Act primarily as precursors for enzyme coenzymes.\n * **Water-Soluble Vitamins:**\n * *Vitamin ext{B}_1 (Thiamine):* Deficiency causes **beriberi** (neurological/cardiac disorders).\n * *Vitamin ext{B}_2$(Riboflavin):* Component of flavin coenzymes ($ ext{FMN, FAD}).\n * *Vitamin ext{B}_3$/ PP (Niacin / Nicotinic Acid):* Component of$ ext{NAD}^+$and$ ext{NADP}^+. Deficiency causes **pellagra**.\n * *Vitamin ext{B}_5 (Pantothenic Acid):* Component of Coenzyme A.\n * *Vitamin ext{B}_6 (Pyridoxine):* Coenzyme for transaminases.\n * *Vitamin ext{B}_7 / H (Biotin):* Coenzyme for carboxylation reactions.\n * *Vitamin ext{B}_9 (Folic Acid / Folacin):* Essential for nucleic acid synthesis and cell division.\n * *Vitamin ext{B}{12} (Cobalamin):* Contains cobalt; necessary for red blood cell formation. Deficiency causes pernicious anemia.\n * *Vitamin C (L-Ascorbic Acid):* Antioxidant, aids collagen synthesis and iron absorption. Deficiency causes **scurvy (kurděje)**.\n * **Fat-Soluble Vitamins:**\n * *Vitamin A (Retinol):* Visual pigment precursor. Deficiency causes **night blindness (šeroslepost)** and xerophthalmia. Provitamin is β-carotene.\n * *Vitamin D (Calciferol / ext{D}3 Cholecalciferol):* Controls Calcium and Phosphorus metabolism. Deficiency causes **rickets (křivice)** in children and osteomalacia in adults.\n * *Vitamin E (Tocopherol):* Major lipid-soluble antioxidant.\n * *Vitamin K (Phylloquinone):* Essential for blood clotting (prothrombin synthesis).\n\n* **Enzymes and Biocatalysis:**\n * Specific biological catalysts composed of proteins that accelerate biochemical reactions by factors of 10^6 ext{ to }10^{12}.\n * **Structure:** **Holoenzyme** = **Apoenzyme** (protein part) + **Cofactor** (non-protein part). If the cofactor is a tightly bound organic molecule, it is a **prosthetic group**; if it is an organic molecule that dissociates readily, it is a **coenzyme**.\n * **Specificity:** High **substrate specificity** (acts only on specific molecules) and **action specificity** (catalyzes only one specific chemical transformation).\n * **Factors Influencing Enzyme Activity:**\n * *Temperature:* Optimal range 10 ext{--}40 ext{ }^∘ ext{C}$; denaturation occurs above$50 ext{--}60 ext{ }^∘ ext{C}.\n * *pH:* Optimal narrow range (usually pH 6–7).\n * *Inhibition Types:*\n * **Competitive Inhibition:** Inhibitor structurally resembles the substrate, competing directly for binding at the **active site**. Overcome by increasing substrate concentration.\n * **Non-Competitive Inhibition:** Inhibitor binds to a site other than the active site, altering catalytic efficiency.\n * **Allosteric Inhibition:** Inhibitor binds to a distinct **allosteric site**, inducing a conformational change in the enzyme that prevents substrate binding.\n * **Major Enzyme Classes:**\n 1. *Oxidoreductases:* Catalyze redox transformations ( ext{NAD}^+, ext{NADP}^+, ext{FMN}, ext{FAD} coenzymes).\n 2. *Transferases:* Catalyze group transfer reactions (e.g., transaminases transferring -NH_2; kinases transferring phosphate).\n 3. *Hydrolases:* Catalyze hydrolytic cleavage of bonds by adding water (e.g., esterases, peptidases, glycosidases).\n 4. *Lyases:* Catalyze non-hydrolytic cleavage or addition of groups across double bonds.\n 5. *Isomerases:* Catalyze intramolecular structural rearrangements.\n 6. *Ligases (Synthetases):* Catalyze bond formation coupled with ATP cleavage energy.\n\n* **Key Metabolic Pathways:**\n * **Metabolism Concepts:** **Anabolism** (endergonic, reductive, energy-requiring synthesis of complex molecules) and **Catabolism** (exergonic, oxidative, energy-yielding breakdown of complex molecules to produce ATP).\n * **Carbohydrate Catabolism (Glycolysis):**\n * Occurs in the cytoplasm of all cells under anaerobic conditions.\n * Conversion of 1 molecule of Glucose (6 ext{ C}$) into 2 molecules of **Pyruvate** ($3 ext{ C}$), yielding a net total of **2 ATP** and **2$ ext{NADH} + ext{H}^+**.\n * *Anaerobic Fate of Pyruvate:* Converted to **Lactate** in animal muscle (lactic fermentation) or **Ethanol + ext{CO}_2$** in yeast (alcoholic fermentation) to regenerate$ ext{NAD}^+.\n * *Aerobic Fate of Pyruvate:* Translocated into mitochondria, oxidatively decarboxylated by Pyruvate Dehydrogenase into **Acetyl-CoA** (2 ext{ C}$) +$ ext{CO}_2$+$ ext{NADH} + ext{H}^+.\n * **Photosynthesis:**\n * *Light Phase (Thylakoids):* Solar light energy absorbed by Chlorophyll in **Photosystems I (P700)** and **II (P680)**. Drives **photolysis of water** (2 ext{H}_2 ext{O} ightarrow ext{O}{2(g)} ↑ + 4 ext{H}^+ + 4e^-$), releasing$ ext{O}_2$, generating **ATP** via photophosphorylation, and reducing$ ext{NADP}^+$to **$ ext{NADPH} + ext{H}^+**.\n * *Dark Phase / Calvin Cycle (Stroma):* Fixation of atmospheric ext{CO}_2$onto Ribulose-1,5-bisphosphate catalyzed by RuBisCO, utilizing ATP and$ ext{NADPH} + ext{H}^+ from the light phase to synthesize glucose.\n * **Lipid Metabolism:**\n * **β$-Oxidation of Fatty Acids:** Occurs inside the mitochondrial matrix. Fatty acids are activated with Coenzyme A, then undergo repeating 4-step cyclic oxidation sequence cleavage at the$β$-carbon, liberating 1 molecule of **Acetyl-CoA** ($2 ext{ C}$) per cycle along with **$ ext{FADH}_2$** and **$ ext{NADH} + ext{H}^+**.\n * *Anabolism of Fatty Acids:* Occurs in the cytoplasm starting from Acetyl-CoA, utilizing ext{NADPH} + ext{H}^+ and ATP.\n * **Protein Metabolism and Urea Cycle:**\n * Dietary proteins hydrolyze to amino acids. Excess amino acids undergo **deamination** (removal of amino group producing toxic ammonia ext{NH}_3).\n * **Ornithine / Urea Cycle (Liver):** Converts toxic ext{NH}_3$and$ ext{CO}_2$into non-toxic **Urea** ($ ext{H}_2 ext{N–CO–NH}_2$) using ATP. Sequence:$ ext{NH}_3 + ext{CO}_2 + ext{ATP} ightarrow ext{Carbamoyl phosphate} ightarrow$combines with **Ornithine** to form **Citrulline**$ ightarrow$reacts with Aspartate to form **Argininosuccinate**$ ightarrow$cleaves Fumarate yielding **Arginine**$ ightarrow hydrolyzed to yield **Urea** and regenerated **Ornithine**.\n * **Citric Acid Cycle (Krebs Cycle):**\n * The central cyclic metabolic pathway in the mitochondrial matrix where acetyl groups from carbohydrates, lipids, and amino acids (in the form of **Acetyl-CoA**) are completely oxidized.\n * Acetyl-CoA (2 ext{ C}$) condenses with Oxaloacetate ($4 ext{ C}$) to form **Citrate** ($6 ext{ C}$). Through a sequence of oxidations and decarboxylations, 2 molecules of$ ext{CO}_2 are released, regenerating Oxaloacetate.\n * Yield per Acetyl-CoA turn: **3 ext{NADH} + ext{H}^+$**, **1$ ext{FADH}_2**, and **1 GTP/ATP**.\n * **Respiratory Chain and Oxidative Phosphorylation:**\n * Located on the inner mitochondrial membrane. Reduced coenzymes ( ext{NADH} + ext{H}^+$,$ ext{FADH}_2$) donate high-energy electrons to a series of membrane electron transporters (flavoproteins, cytochromes) ending at terminal electron acceptor$ ext{O}_2$to produce$ ext{H}_2 ext{O}$$. * Proton pumping across the inner membrane creates a electrochemical proton gradient that drives ATP Synthase to produce vast amounts of ATP via oxidative phosphorylation.