Intro to General, Organic, and Biochemistry: Chapters 7, 8, 9, and 10

Comprehensive practice flashcards covering chemical quantities, stoichiometry, gas laws, solutions, tonicity, acids, bases, chemical equilibrium, and buffers.

What is Avogadro's number, and what quantity does one mole represent?

Avogadro's number is $6.02 \times 10^{23}$; one mole represents $6.02 \times 10^{23}$ items (atoms, molecules, or ions).

How are the subscripts in a chemical formula utilized as conversion factors?

The subscripts show the moles of each element present in $1\,\text{mole}$ of the compound (e.g., in aspirin, $C_9H_8O_4$, there are $9\,\text{moles of C}$, $8\,\text{moles of H}$, and $4\,\text{moles of O}$ per $1\,\text{mole of compound}$).

What is molar mass, and in what units is it expressed?

Molar mass is the mass of $1\,\text{mole}$ of an element or compound, equal to its atomic or formula mass expressed in grams per mole ($g/mol$).

What does the delta ($\Delta$) symbol written over a reaction arrow indicate in a chemical equation?

The $\Delta$ sign indicates that heat is used to start the reaction.

How do combination and decomposition reactions differ?

In a combination reaction, two or more reactants combine to form a single product ($A + B \rightarrow AB$); in a decomposition reaction, one reactant splits into two or more simpler substances ($AB \rightarrow A + B$).

What defines single replacement and double replacement reactions?

In a single replacement reaction, one element takes the place of another element in a compound ($A + BC \rightarrow AC + B$); in a double replacement reaction, the positive ions in two reacting compounds switch places ($AB + CD \rightarrow AD + CB$).

What are the products of complete versus incomplete combustion of a hydrocarbon?

Complete combustion (sufficient oxygen) yields $CO_2(g)$, $H_2O(g)$, and energy; incomplete combustion (limited oxygen) yields $CO(g)$, $H_2O(g)$, and heat.

According to the 'OIL RIG' mnemonic, how are oxidation and reduction defined in terms of electron transfer?

'Oxidation Is Loss' of electrons (resulting in a more positive charge); 'Reduction Is Gain' of electrons (resulting in a more negative charge).

What three conditions must be satisfied for a chemical reaction to occur according to collision theory?

1. Collision: The reactants must collide.\n2. Orientation: The reactants must align properly to break and form bonds.\n3. Energy: The collision must provide the energy of activation ($E_a$).

How do exothermic and endothermic reactions differ regarding energy and heat of reaction?

In an exothermic reaction, the energy of the products is less than the reactants, and heat is released (a product); in an endothermic reaction, the energy of the products is greater than the reactants, and heat is absorbed (a reactant).

How does a catalyst increase the rate of a chemical reaction?

A catalyst increases the reaction rate by lowering the energy of activation ($E_a$) without being consumed in the reaction.

What are the standard equivalences for atmospheric pressure at sea level in atmospheres, millimeters of mercury, and torr?

$1\,\text{atm} = 760\,\text{mmHg} = 760\,\text{Torr}$.

What does Boyle's law state, and what is its mathematical expression?

Boyle's law states that the pressure of a gas is inversely related to its volume when temperature ($T$) and moles ($n$) are constant: $P_1V_1 = P_2V_2$.

How does Boyle's law explain the mechanics of inhalation during breathing?

During inhalation, the lungs expand (volume increases), which causes internal lung pressure to decrease below atmospheric pressure, allowing air to flow into the lungs.

What does Charles's law state, and what temperature scale is required for its calculations?

Charles's law states that the volume of a gas is directly related to its temperature when pressure ($P$) and moles ($n$) are constant: $\frac{V_1}{T_1} = \frac{V_2}{T_2}$; temperature must always be expressed in Kelvin ($K$).

What does Gay-Lussac's law state, and what is its formula?

Gay-Lussac's law states that the pressure exerted by a gas is directly related to its Kelvin temperature when volume ($V$) and moles ($n$) are constant: $\frac{P_1}{T_1} = \frac{P_2}{T_2}$.

What is the formula for the combined gas law when the amount of gas ($n$) remains constant?

$\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$.

What are the conditions of STP, and what is the molar volume of an ideal gas at STP?

Standard Temperature and Pressure (STP) conditions are $273\,K$ ($0\,^\circ\text{C}$) and $1\,\text{atm}$; at STP, $1\,\text{mole}$ of any gas occupies a molar volume of $22.4\,L$.

What does Dalton's law of partial pressures state?

Dalton's law states that the total pressure exerted by a mixture of gases is the sum of the partial pressures of those individual gases: $P_{\text{total}} = P_1 + P_2 + P_3 + \dots$.

How are solute and solvent differentiated in a solution?

The solute is the substance present in the lesser amount that dissolves, while the solvent is the substance present in the much larger amount.

What does the phrase 'like dissolves like' mean in terms of solution formation?

Solutions will form when the solute and solvent have similar polarities: polar solutes dissolve in polar solvents, and nonpolar solutes dissolve in nonpolar solvents.

How do strong electrolytes, weak electrolytes, and nonelectrolytes behave in water?

Strong electrolytes dissociate $100\%$ into ions and conduct electricity strongly; weak electrolytes dissociate only slightly to produce a few ions; nonelectrolytes dissolve only as molecules without producing ions and do not conduct electricity.

What is an equivalent ($Eq$) in solution chemistry?

An equivalent ($Eq$) is the amount of an electrolyte or ion that provides $1\,\text{mole}$ of electrical charge ($+$ or $-$), calculated as: $\text{equivalents} = \text{moles} \times \text{charge}$.

How does temperature affect the solubility of most solids compared to gases in water?

The solubility of most solids increases as temperature increases, whereas the solubility of gases decreases as temperature increases.

What does Henry's law state regarding the relationship between gas solubility and pressure?

Henry's law states that the solubility of a gas in a liquid is directly related to the pressure of that gas above the liquid; higher pressures force more gas molecules into solution.

What is the formula and definition of molarity ($M$)?

Molarity is the number of moles of solute per liter of solution: $M = \frac{\text{moles of solute}}{\text{liters of solution}}$.

What equation is used to calculate changes in concentration and volume during a dilution?

$M_1V_1 = M_2V_2$ (or $C_1V_1 = C_2V_2$), where the initial mass/moles of solute remain constant while volume increases and concentration decreases.

How do solutions, colloids, and suspensions differ regarding filtration and semipermeable membranes?

Solutions have small particles that pass through both filter paper and semipermeable membranes; colloids have medium-sized particles that pass through filter paper but are retained by semipermeable membranes; suspensions have large particles that settle and can be separated by filter paper.

What happens to a red blood cell placed in hypotonic versus hypertonic solutions?

In a hypotonic solution, water enters the cell, causing it to swell and burst (hemolysis); in a hypertonic solution, water exits the cell, causing it to shrink (crenation).

How do the Arrhenius and Brønsted-Lowry theories define acids and bases?

Arrhenius: Acids produce $H^+$ (protons) in water, bases produce $OH^-$ (hydroxide ions).\nBrønsted-Lowry: An acid is an $H^+$ donor, while a base is an $H^+$ acceptor.

What is a conjugate acid-base pair?

Two substances related by the loss or gain of a single proton ($H^+$); an acid loses $H^+$ to form its conjugate base, while a base gains $H^+$ to form its conjugate acid.

What are the six common strong acids listed in the lecture?

Hydroiodic acid ($HI$), hydrobromic acid ($HBr$), perchloric acid ($HClO_4$), hydrochloric acid ($HCl$), sulfuric acid ($H_2SO_4$), and nitric acid ($HNO_3$).

What conditions define a chemical system at equilibrium?

Equilibrium is reached when the rate of the forward reaction equals the rate of the reverse reaction, and there are no further changes in the concentrations of reactants and products.

What does Le Châtelier's principle state?

When a stress or disturbance is placed on a system at equilibrium, the rates of the forward and reverse reactions change to relieve that stress and reestablish equilibrium.

What is the formula for calculating pH, and what does the ion product constant of water ($K_w$) equal?

$pH = -\log[H_3O^+]$; in aqueous solution at standard conditions, $K_w = [H_3O^+][OH^-] = 1.0 \times 10^{-14}$.

What products are generated when an acid reacts with a metal carbonate or bicarbonate?

An acid reacts with a carbonate or bicarbonate to produce carbon dioxide gas ($CO_2$), a salt, and water ($H_2O$).

What are the components of a buffer solution, and what is its function?

A buffer consists of a weak acid and a salt of its conjugate base; it resists drastic changes in pH by absorbing added $H_3O^+$ or $OH^-$, maintaining blood pH close to $7.4$.