UPCAT - Chemistry

Organic Chemistry

the study of the structure and properties of carbon-containing compounds

Inorganic Chemistry

the study of the structure and properties of inorganic compounds or compounds not composed of carbons

Analytical Chemistry

* determination of composition and properties of matter
* studies what is in a sample of an object/matter or what is that sample composed of

Physical Chemistry

* studies the physical and fundamental aspects of chemical system and processes
* one major topic discuseed is the energy involved in chemical reactions and physical changes in matter

Biochemistry

studies the chemicals and chemical reactions found in living organisms

Law of Conservation of Mass

matter cannot be created nor destroyed, but only changed from one form to another

Law of Constant Composition

a given compound always contains exactly the same proportion of elements by mass

Law of Multiple Proportions

the amount of elements that react with each other can be reduced to small whole numbers

mass of an atom

protons + neutrons

plum-pudding model

positively-charged sphre dotted with electrons

Rutherford model

atom is mostly empty space with most of its mass in the nucleus with electrons moving around it

modern atomic theory

atoms are made out of protons, neutrons, and electrons with the protons and neutrons residing in the nucleus while the electrons move around

Group IA (Alkali Metals)

Lithium, Sodium, Potassium, Rubidium, Cesium, Francium

Group IIA (Alkaline Earth Metals)

Beryllium, Magnesium, Calcium, Strontium, Barium, Radium

Group VIA (Chalcogens)

Oxygen, Sulfur, Selenium, Tellerium, Polonium, Livermonium

Group VIIA (Halogens)

Fluorine, Chlorine, Bromine, Iodine, Astatine, Tennessine

Group VIIIA (Noble Gas)

Helium, Neon, Argon, Krypton, Xenon, Radon, Oganesson

Isotopes

atoms with identical atomic nmbers but different mass numbers (that is th same number of protons but a different number of neutrons)plasma

cations vs anions

cations are postively charged isotopes which lack electrons while anions are negatively charged isotpoes which lack protons

ionic copounds

made up of cations and anions and are bound by electrostatic forces (opposite charges attract)

electronic configuration mnemonic

Si Santos pumasok sa pinto, si Diego pumasok sa door. Pumunta si Fiona dumaan papunta sa faculty dala sila,

orbital capacities of s, p, d, and f

2, 6, 10, and 14

activity series of metals mnemonic

Please stop calling me a careless Zebra. Instead, try learning how Copper Saves Gold

activity series of metals from most reactive to least reactive

Potassium, Sodium, Calcium, Magnesium, Aluminum, Carbon, Zinc, Iron, Tin , Lead, Hydrogen, Copper, Silver, Gold

physical change

changes only the state of matter, not its composition

chemical change

alters the composition and identity of the substance and will inherit properties different to the chemicals before the change

indicators of chemical change

change in color, temperature, flame color, formation of precipitate, and formation of bubbles

physical property of matter

* property that involves physical change
* can be measured without converting matter into another substance (e.g. boiling point, hardness)

intensive physical property vs. extensive physical property

* intensive: does not depend on amount (e.g. color)
* entensive: depends on amount (e.g. volume, mass)

chemical property

* matter will be converted into another substance during measurement of this property
* example: flash point, toxicity

pure substance

* matter that is constant in composition and properties does not vary
* cannot by phusically separated

element

* simplest form of matter and cannot be broken down into simple substances
* composed of atoms

compound

* composed of two or mroe elements
* can be broken down into individual elements
* have different properties than parent elements

mixtures

* composed of two or more pure substances of varying composition
* can be physically separated

homogeneous mixture (solution)

* occurs in a single phase
* components cannot be distinugished from each other

heterogeneous mixture

* occurs as two or more phases
* components can be distinguished from each other
* two types: colloids and suspensions

colloids

* large than the size of a molecule but smaller than what can be seen with the anked eye
* substance’s dimensions must be between 1 and 1000 nanometers
* exhibits the Tyndall Effect

suspension

* mixture between a liquid and particles of a solid
* particles do not dissolve and solid particles will settle and separate over time

Solid sol

* a colloid between a solid and a solid
* example: Ruby glass

Solid emulsion/gel

* a colloid between a solid medium and a dispersed liquid
* example is pearl or cheese

solid foam

* a colloid between a solid medium and dispersed gas
* example is lava and pumice

sol

* a colloid between a liquid medium and dispersed solid
* a colloidal suspension with solid particles in a liquid
* paints, cell fluids

emulsion

* is a colloid between two liquids
* examples are milk and oil in water

foam

* a colloid between a liquid medium and a gas
* is formed when many gas particles are trapped in a liquid
* examples are soap suds and whipped cream

aerosol

* a colloid between a gas medium and dispersed solid or liquid
* contains small particles of liquid or solid dispersed in a gas
* examples are smoke, fog, and mist

Tyndall Effect

the phenomenon in which light is scattered by particles of matter in its path

mass, density, and volume formula

M = DV

moles of reactant required in a reaction

moles of reactant \* (amount of product/amount of reactant)

Avogadro’s number

* the ratio that relates the number of constituent particles in a sample with the amount of substance in that sample
* equivalent to **6.02*10^23**

number of moles to molecules

number of moles \* Avogadro’s number

molarity

* a unit of concentration expressed as the number of moles of dissolved solute per liter of solution
* mol solute/L solution

ppm and ppb

* used in solutions with low concentrations of a solute
* ppm = (grams of solute/grams or mL of solution) \* 10^6
* ppb = (grams of solute/grams or mL of solution) \* 10^9

mass percent

(mass of component of solution/total mass of solution) \* 100%

mole fraction formulas

* (n/n)% = moles of solute/total number of moles
* (n/n)% = partial pressure/total pressure

partial pressure formula

P_A = X_A \* P_T

Dalton’s Law

* total pressure is equal to all partial pressures
* all mole fractions is equal to 1

volume percent formula

volume% = (volume of component of solution/total volume of solution)\*100%

constitution of a chemical equation

* on the left are the reactants
* on the right are the products
* the initals written in parenthesis (e.g. HCl(aq)) defines their states
* solid, liquid, gas - (s), (l), (g)
* substance is dissolved in water - (aq)

Combination (Synthesis) Reaction

* two or more products form a single product
* 2Na(s) + Cl_2(g) → 2NaCl(s)

Decomposition Reaction

* a single compound breaks down into two or more products
* 2KClO_3(s) → 2KCl(s) + 3O_2(g)

Single displacement reaction

* one of the components of one of the reactants is replaced by another reactant
* always a redox reaction
* Zn(s) + 2HCl(aq) → ZnCl_2(aq) + H_2(g)

Double displacement (metathesis) reaction

* reactants exhange parts
* BaCl_2(aq) + Na_2SO_4(aq) → BaSO_4(s) + 2NaCl(aq)

Combustion reaction

* carbon-containing compounds react with oxygen to form CO2 and H2O **as water vapor**
* CH_4(g) + 2O_2(g) → CO_2(g) + 2H_2O(g)

Redox reaction

this is the reaction that involves the transfer of electrons

reducing agent

* the element that loses electrons in a redox reaction (a.k.a. the one that is oxidized)
* metals

oxidizing agent

* the element that gains electrons in a redox reaction (a.k.a. the one hat is reduced)
* non-metals

oxidation number of a pure element

0

oxidation number of monoatomic ions

equal to their charge (e.g. Fe-2 = -2)

oxidation number of Group I and II

if in a compound with other elements or is in its ionic form, +1 and +2 respectively (excluding H)

oxidation number of H

if in a compound with metals (a hydride compound), then -1 else +1

oxidation number of Al and F in compounds

\+3 and -\`1

oxidation number of O

\-2 except in hydrogen peroxide (H_2O_2) and peroxide anion (O_2 -2) where it is -1

oxidation number of halogens

negative oxidation number on halide compounds and positive oxidation number of oxygen-containing compounds

oxidation number of polyatomic ions

the algebraic sum of the oxidation number of each element is equivalent to the ion’s charge

oxidation number for neutral compounds

the algebraic sum of the oxidation number of each element is equivalent to zero

Kinetic-Molecular Theory

* a model that explains the behavior of gases where external forces are applied
* the higher the temperautre, the faster the particles move
* at the same temperature:
* larger particles move slower
* smaller particles move faster

Boyle’s Law

* pressure is in an inverse relationship with volume
* P1V1 = P2V2

Charles’s Law

* the temperature of a gas is directly proportional to its volume
* T1/V1 = T2/V2

Gay-Lussac’s Law

* pressure is directly propertional to temperature
* T1/P1 = T2/P2

Avogadro’s Law

* the volume of a gas is directly propertional to its amount (mol)
* n1/V1 = n2/V2

Ideal Gas Law

PV = nRT; R = 0.08206 L-atm/mol-k

effusion vs. diffusion

* effusion is the ability of a gas to pass through a small orifice into an evaculated chamber
* diffusion is the ability of a gass to distribute itself homogeneously

Graham’s Law of Effusion and Diffusion

* the rate of an effusion/diffusion of a gas is inversely proportional to its molar mass
* r1/r2 = sqrt(M1)/sqrt(M2)

open system

there is an exchange of heat and matter between the system and its surroundings

closed system

there is only an exchange ofheat between the system and its surroundings

isolated system

netiher energy nor matter is exchanged

thermochemistry

branch of chemistry that deals with the energy changes during a chemical reaction

thermochemicals

any chemical equation that has heat on either the product or reactant side of the equation

exothermic vs endothermic

* exothermic: heat is released and is on the product side of the equation
* endothermic: heart is required for the reaction to proceed and is on the reactant side of the equation

heat

is a process of gaining or losing energy

work

is a transfer of energy, which does not involve temperature changes

First law of thermodynamics

* the net change of total energy of a system is equal to the heat added into the system minus the work done
* ΔU = q - w; q = heat added, w = work done

Second law of thermodynamics

the total entropy must increase in every spontaneous process

spontaneous processes

* processes that occur wihtout intervention
* processes tend to havor states with low energy and high entropy

enthalpy

* indicates the transfer of heat from or into the thermodynamic system
* ΔH = ΔU + pΔV
* ΔH = ΔP - RTΔn for gases

entropy

* measure of randomness or disorder in a system
* ΔS= qrev/T; qrev = amount of heat in a reversible process, T = temperature

Gibbs free energy (G)

* tells us the spontaneity of a process
* ΔG = ΔH - TΔS
* -ΔG = spontaneous, +ΔG = not spontaneous

molecular vs. emperical formula

* molecular formula presents the exact number of elements in a compound whileas emperical only has the ratio
* molecular: C6H14
* emperical: C3H7

combining a cation and an anion

* the charge of the cation becomes the subscript of the anion
* the charge of the anion becomes the subscript of the cation
* divide by the GCF if possible

alkanes, alkenes, and acetylenes

* alkanes: single bond between carbon atoms; saturated hydrocarbons
* alkenes: double bond between carbon atoms: unsaturated hydrocarbons
* acetylenes: triple bond between carbon atoms; unsaturated hydrocarbons