Chapter 6: Thermochemistry

These flashcards focus on key vocabulary and concepts related to thermochemistry, including definitions of terms and explanations of fundamental concepts.

Thermochemistry

A branch of thermodynamics that deals with heat involved in chemical and physical changes.

System

The contents of the reaction flask during a thermochemical process.

Surroundings

Everything outside the system, including the reaction flask itself.

Internal Energy (E)

The sum of potential and kinetic energy of all the particles in a system.

Enthalpy (H)

A measure of the total heat content of a system at constant pressure.

Calorimetry

The process of measuring the heat of a chemical or physical change.

Hess's Law

States that the total enthalpy change during a chemical reaction is the same, regardless of the number of steps in the reaction.

Heat (q)

Energy transferred as a result of temperature difference.

Work (w)

Energy transferred when an object is moved by a force.

First Law of Thermodynamics

States that the total energy of the universe is constant; energy can neither be created nor destroyed.

Exothermic Process

A process in which heat is released to the surroundings.

Endothermic Process

A process in which heat is absorbed from the surroundings.

Calorie (cal)

The amount of energy needed to raise the temperature of 1 gram of water by 1ºC.

Specific Heat Capacity (c)

The quantity of heat required to change the temperature of 1 gram of a substance by 1 K.

Pressure-Volume Work (w)

Work done when the volume of the system changes in the presence of an external pressure.

State Function

A property whose value does not depend on the path taken to reach that specific value.

Standard State

The standard condition under which the properties of a substance are measured (1 atm, 25ºC).

Heat Capacity (C)

The quantity of heat required to change the temperature of a substance by 1 K.

Nutritional Calorie (Cal)

A measure of energy equal to 1,000 calories.

ΔE

The change in internal energy of a system.

Stoichiometry of Thermochemical Equations

The calculation of heat changes associated with chemical reactions based on the stoichiometric coefficients.