Thermochemistry Study Notes chapter 6

Vocabulary flashcards created from Thermochemistry lecture notes, covering key definitions and concepts.

Thermodynamics

The study of heat and its transformations.

Thermochemistry

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

System

The part of the universe being studied, which can interact with surroundings.

Surroundings

Everything outside the system that can exchange energy or matter with it.

Open system

A system that can freely exchange energy and matter with its surroundings.

Closed system

A system that can exchange energy with its surroundings, but not matter.

Isolated system

A system that does not interact with its surroundings.

Energy

The capacity to do work.

Work

The action of forces through distances.

Potential Energy

Stored energy due to position or configuration.

Kinetic Energy

The energy of motion.

Thermal Energy

The energy associated with the temperature of a system.

Chemical Energy

Energy stored in the bonds of chemical compounds.

Law of Conservation of Energy

Energy cannot be created or destroyed; it can only change forms.

SI unit of energy

The joule (J), equivalent to 1 kg m² s⁻².

Calorie (cal)

The quantity of energy needed to raise the temperature of 1 g of water by 1 °C.

Nutritional calorie (Cal)

A unit used in diet tables equivalent to 1 kilocalorie (kcal).

British thermal unit (Btu)

A unit of energy indicating the output of appliances; energy required to raise 1 lb of water by 1 °F.

Internal Energy (U)

The total energy contained within a system, consisting of both potential and kinetic energy.

Enthalpy (H)

A thermodynamic quantity equal to the internal energy plus the product of pressure and volume.

Exothermic Reaction

A reaction that releases heat, raising the temperature of its surroundings.

Endothermic Reaction

A reaction that absorbs heat, lowering the temperature of its surroundings.

Calorimetry

The science of measuring heat exchanged during physical or chemical processes.

Specific Heat Capacity (Cs)

The amount of heat required to raise the temperature of 1 g of a substance by 1 K.

Molar Heat Capacity (Cp,m)

The amount of heat required to raise the temperature of 1 mole of substance by 1 K.

State Functions

Properties that depend only on the current state of the system, not how it reached that state.

Path Dependent Functions

Properties that depend on the path taken to reach a state, such as heat and work.

Heat Capacity (C)

The amount of heat needed to change the temperature of a substance by 1 K.

First Law of Thermodynamics

The total energy of the universe remains constant; energy can be transformed but not created or destroyed.

ΔH (Change in Enthalpy)

The difference in enthalpy between the products and reactants in a chemical reaction.

Hess's Law

The total enthalpy change for a reaction is the sum of the enthalpy changes for each step of the reaction.

Standard State

Defined conditions (1 bar and specified temperature) under which enthalpy values are measured.