Chemistry Quiz: Gas Laws and Molarity

A chemical reaction's enthalpy change is the heat change at constant pressure. It's the heat energy transferred between a system and its surroundings during a process at constant pressure.

The energy change of a system is the sum of the heat exchanged (q) and the work done (w) on or by the system.

The amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius.

The relationship between the pressure, volume, moles, and temperature of an ideal gas.

The ratio of the actual yield of a reaction to the theoretical yield, expressed as a percentage.

The standard enthalpy change of formation (ΔHf°) is the enthalpy change when one mole of a compound is formed from its elements in their standard states under standard conditions (298 K and 1 atm).

The enthalpy change for a reaction (ΔHrxn) can be calculated using the standard enthalpy change of formation values of the reactants and products according to Hess's Law. It's the heat change for the reaction under standard conditions.

The mole fraction of a component in a mixture is the ratio of the number of moles of that component to the total number of moles in the mixture. It represents the relative abundance of a component.

The van der Waals equation is a modified version of the ideal gas law that accounts for the intermolecular forces and the finite volume of gas molecules. It provides a more realistic description of real gases.

The rate of a reaction is influenced by the concentration of reactants. Increasing the concentration of reactants typically increases the reaction rate.

The rate of a reaction is influenced by the temperature. Increasing the temperature typically increases the reaction rate due to increased kinetic energy of molecules.

The Kc equilibrium constant relates the equilibrium concentrations of reactants and products in a reaction. It indicates the relative amounts of reactants and products at equilibrium.

The density of a gas can be calculated using the Ideal Gas Law (PV = nRT) rearranged to solve for density (d = PM/RT).

The identity of an element can be determined by analyzing the mass ratio of the elements in a compound and using the formula's information to calculate its molar mass.

Boyle's Law (P₁V₁ = P₂V₂) states that the pressure and volume of a gas are inversely proportional at constant temperature. This means that as volume decreases, pressure increases.

The ionization energy represents the energy required to remove an electron from a gaseous atom or ion. The greater the ionization energy, the more difficult it is to remove an electron (and thus, the less likely it is to form an anion - which gains an electron).

Electron affinity is the change in energy when an electron is added to a gaseous atom or ion. A more negative electron affinity indicates a greater tendency for an atom to gain an electron.

Density is the amount of mass per unit volume. The density of a gas is affected by temperature - when heated, density decreases, and as the gas cools, density increases.

The reaction of chlorine with carbon disulfide produces carbon tetrachloride and sulfur. This reaction is exothermic, meaning it releases heat energy into the surroundings.

The Ideal Gas Law describes the relationship between pressure, volume, temperature, and the number of moles of an ideal gas. It can be used to predict the behavior of gases under different conditions.

The energy change associated with a chemical reaction under standard conditions (typically 298 K and 1 atm).

The enthalpy change that occurs during the complete combustion of one mole of a substance under standard conditions.

The sum of the squares of the oxidation numbers of the elements in a compound must equal zero.

The oxidation state of an element in its elemental (uncombined) form is zero.

The oxidation state of oxygen in most compounds is -2.

The oxidation state of hydrogen in most compounds is +1.

Hess's Law states that the enthalpy change for any overall reaction is the sum of the enthalpy changes for the individual steps involved in the reaction.

The enthalpy of formation (∆Hf°) is the enthalpy change that occurs when one mole of a substance is formed from its elements in their standard states. The standard state is the most stable form of the element at 298 K and 1 atm pressure.

The heat capacity (C) is the amount of heat energy required to raise the temperature of a substance by 1°C. It is a measure of how much energy a substance can store for a given temperature change.

A combustion reaction is a chemical reaction involving the rapid reaction between a substance with an oxidant, usually oxygen, to produce heat and light.

Molar mass is the mass of one mole of a substance. It is usually expressed in units of g/mol.

The partial pressure of a gas in a mixture is the pressure that the gas would exert if it were the only gas present in the container.

Graham's law states that the rate of effusion of a gas is inversely proportional to the square root of its molar mass. The lighter the gas, the faster it will effuse.

The condition where the forward and reverse reaction rates are equal, resulting in no net change in concentrations of reactants and products.

The change in concentration of a reactant or product over a specific unit of time, describing how fast a reaction proceeds.

The minimum energy required for a reaction to occur. Raising the temperature increases the number of molecules with enough energy to react.

A substance that speeds up a reaction without being consumed in the process. It lowers the activation energy.

The sum of the exponents of the concentration terms in the rate law. Reflects the number of molecules that collide in the rate-determining step.

A reaction that occurs in multiple steps with the slowest step determining the overall rate of the reaction.