Thermochemistry Flashcards

Vocabulary flashcards for Thermochemistry lecture notes.

Energy

The ability to do work or transfer heat.

Work

Energy used to cause an object that has mass to move.

Heat

Energy used to cause the temperature of an object to rise.

Kinetic Energy

Energy an object possesses by virtue of its motion.

Potential Energy

Energy an object possesses by virtue of its position or chemical composition.

Joule (J)

The SI unit of energy.

Calorimetry

Measures heat flow.

System

The molecules we want to study.

Surroundings

Everything else besides the molecules we want to study.

Work (Thermodynamics)

Energy used to move an object over some distance.

Heat Flow

Heat flows from warmer objects to cooler objects.

First Law of Thermodynamics

Energy is neither created nor destroyed; the total energy of the universe is constant.

Internal Energy (E)

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

Change in Internal Energy (ΔE)

The final energy of the system minus the initial energy of the system.

Endergonic

System absorbs energy from the surroundings (ΔE > 0).

Exergonic

System releases energy to the surroundings (ΔE < 0).

Endothermic Process

When heat is absorbed by the system from the surroundings.

Exothermic Process

When heat is released by the system into the surroundings.

Enthalpy (ΔH)

ΔH = ΔE + PΔV

Calorimetry

The measurement of heat flow.

Specific Heat Capacity (Specific Heat)

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

Hess’s Law

If a reaction is carried out in a series of steps, ΔH for the overall reaction will be equal to the sum of the enthalpy changes for the individual steps.

Enthalpy of Formation (ΔHf)

The enthalpy change for the reaction in which a compound is made from its constituent elements in their elemental forms.

Standard Enthalpies of Formation (ΔHf°)

Enthalpies of formation measured under standard conditions (25 °C and 1.00 atm pressure).