Chapter 6: Thermochemistry

These flashcards cover key vocabulary terms and definitions from the chapter on Thermochemistry in General Chemistry.

Thermochemistry

The study of heat changes in chemical reactions.

Heat of Reaction (q)

The heat change needed to bring a system back to its starting temperature after a reaction.

Enthalpy (H)

The total heat content of a system, including internal energy, pressure, and volume.

Exothermic Process

A reaction that releases heat, making the reaction vessel feel warm.

Endothermic Process

A reaction that absorbs heat, making the reaction vessel feel cool.

Law of Conservation of Energy

Energy can change forms, but the total amount of energy always stays the same.

Kinetic Energy (EK)

Energy of motion, calculated as (1/2)mv^2.

Potential Energy (EP)

Energy an object has due to its position or state.

Thermodynamic System

The specific part of the universe being studied where a change occurs.

Calorimeter

A device used to measure heat changes during physical or chemical processes.

Hess's Law

If a reaction occurs in steps, the total enthalpy change for the overall reaction is the sum of the enthalpy changes for each step.

Standard Enthalpy of Formation (\DeltaHf°)

The heat change when one mole of a substance is formed from its basic elements in their standard states.

Extensive Property

A property that depends on the amount of substance present, like mass or volume.

Specific Heat Capacity (s)

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

Thermochemical Equation

A chemical equation that includes the enthalpy change (\DeltaH) for the reaction.

Heat Capacity (C)

The heat required to raise the temperature of a sample of a substance by one degree Celsius.

Standard State

A set of standard conditions (usually 1 atm pressure and a specific temperature) for comparing substances.

Allotropes

Different forms of the same element in the same physical state (e.g., graphite and diamond are allotropes of carbon).

Change in Enthalpy (\DeltaH)

The difference between the enthalpy of the products and the enthalpy of the reactants in a chemical