Gen Chem 1 Study Guide: Aqueous Reactions and Gases

Vocabulary flashcards covering core terms, definitions, and laws from Chapter 4 (Aqueous Reactions) and Chapter 5 (Gases).

Solution

A homogeneous mixture composed of a solute (the dissolved substance present in a smaller amount) dissolved in a solvent (the substance that does the dissolving, present in a larger amount).

Aqueous

Dissolved in water, denoted by the state symbol $(aq)$.

Soluble / Insoluble

Soluble means that a significant amount of a substance dissolves; insoluble means very little dissolves, leaving the substance as a solid $(s)$ that precipitates.

Electrolyte

A substance that produces ions when dissolved in water and conducts electricity.

Strong Electrolyte

A substance that dissociates $100\%$ into ions in water, such as soluble ionic compounds, strong acids, and strong bases, producing bright light in a conductivity test.

Weak Electrolyte

A substance that only partially ionizes in water (such as weak acids and weak bases), existing as both molecules and ions and giving a dim light in a conductivity test.

Nonelectrolyte

A substance that dissolves entirely as whole molecules without forming ions (such as sugar or ethanol) and gives no light in a conductivity test.

Molarity ($M$)

A concentration unit defined as moles of solute per liter of solution ($M = \frac{\text{mol}}{\text{L}}$).

Precipitate

An insoluble solid formed when a chemical reaction occurs in solution.

Spectator Ions

Ions that appear unchanged on both sides of a chemical equation and are eliminated to form the net ionic equation.

Acid (Arrhenius/Brønsted-Lowry)

A chemical species that functions as a proton ($H^+$) donor.

Base (Arrhenius/Brønsted-Lowry)

A chemical species that functions as a proton acceptor or an $OH^-$ producer.

Indicator

A chemical substance that changes color depending on pH (for example, phenolphthalein is colorless in acid and pink in base).

Equivalence Point

The stage in a titration where the moles of acid equal the moles of base, representing complete stoichiometric reaction.

Endpoint

The point during a titration at which the added indicator changes color.

Oxidation

The loss of electrons during a reaction, resulting in an increase in oxidation state.

Reduction

The gain of electrons during a reaction, resulting in a decrease in oxidation state.

Oxidizing Agent

The species that undergoes reduction by accepting electrons from another species.

Reducing Agent

The species that undergoes oxidation by donating electrons to another species.

Redox Reaction

Any chemical reaction in which electrons are transferred between species, leading to changes in oxidation states.

Hydration

The process by which polar water molecules surround dissolved ions, orienting the partial negative ($\delta^-$) oxygen end toward cations and the partial positive ($\delta^+$) hydrogen ends toward anions.

Strong Acids (7)

The seven acids that ionize completely in water: $HCl$, $HBr$, $HI$, $HNO_3$, $H_2SO_4$, $HClO_4$, and $HClO_3$.

Strong Bases

Bases that ionize completely in water, consisting of Group 1 hydroxides ($LiOH$, $NaOH$, $KOH$, $RbOH$, $CsOH$) and heavier Group 2 hydroxides ($Ca(OH)_2$, $Sr(OH)_2$, $Ba(OH)_2$).

Pressure ($P$)

Force per unit area, caused by gas particles colliding with container walls.

Barometer

An instrument designed to measure atmospheric pressure.

Manometer

An instrument designed to measure the pressure of an enclosed gas sample inside a container.

STP

Standard Temperature and Pressure, defined as $0\,^\circ\text{C}$ ($273.15\,\text{K}$) and $1\,\text{atm}$ (or $1\,\text{bar}$ in newer texts), where $1\,\text{mol}$ of an ideal gas occupies approximately $22.4\,\text{L}$.

Ideal Gas

A hypothetical gas whose particles occupy no volume and experience no attractive forces between one another.

Partial Pressure

The pressure that an individual gas in a gas mixture would exert if it were present alone in the entire container volume.

Mole Fraction ($X$)

The ratio of the number of moles of one component to the total number of moles present in a mixture ($X = \frac{n_A}{n_{\text{total}}}$).

Diffusion

The process by which gas particles spread through a space or through another gas.

Effusion

The escape of gas particles from a container through a tiny hole into an evacuated chamber or vacuum.

Mean Free Path

The average distance that a gas particle travels between successive collisions, which becomes longer at lower pressures.

Root-Mean-Square (rms) Speed ($u_{\text{rms}}$)

A type of average speed of gas particles defined by the formula $u_{\text{rms}} = \sqrt{\frac{3RT}{M}}$, using $R = 8.314\,\text{J}\,\text{mol}^{-1}\,\text{K}^{-1}$ and molar mass $M$ in $\text{kg}\,\text{mol}^{-1}$.

Real Gas

A gas that deviates from ideal behavior due to particle volume and intermolecular attractions, occurring particularly at high pressure and low temperature.

Boyle's Law

Gas law stating that pressure and volume are inversely proportional ($P_1V_1 = P_2V_2$) when amount of gas ($n$) and temperature ($T$) are kept constant.

Charles's Law

Gas law stating that volume and absolute temperature are directly proportional ($\frac{V_1}{T_1} = \frac{V_2}{T_2}$) when amount of gas ($n$) and pressure ($P$) are kept constant.

Gay-Lussac's Law

Gas law stating that pressure and absolute temperature are directly proportional ($\frac{P_1}{T_1} = \frac{P_2}{T_2}$) when amount of gas ($n$) and volume ($V$) are kept constant.

Avogadro's Law

Gas law stating that volume and amount of gas in moles are directly proportional ($\frac{V_1}{n_1} = \frac{V_2}{n_2}$) when pressure ($P$) and temperature ($T$) are kept constant.

Dalton's Law of Partial Pressures

Gas law stating that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the individual gases ($P_{\text{total}} = P_1 + P_2 + \dots$).

Graham's Law

Gas law stating that the rate of effusion of a gas is inversely proportional to the square root of its molar mass ($\frac{\text{rate}_1}{\text{rate}_2} = \sqrt{\frac{M_2}{M_1}}$).

Van der Waals Constants ($a$ and $b$)

Constants in the real gas equation $\left(P + \frac{an^2}{V^2}\right)(V - nb) = nRT$, where $a$ corrects for attractive forces between particles and $b$ corrects for the finite volume occupied by the particles.