Unit 6: Thermodynamics

Exothermic

is when energy is transferred from the system to the surroundings, such as when a chemical reaction occurs in a beaker and the beaker feels hot.

Hess’s Law

states that if a reaction can be broken into a series of steps, the sum of the ΔH of those steps are equal to the ΔH of the reaction.

Enthalpy change

is the measure of energy that is released or absorbed when bonds are broken /formed.

Temperature

remains constant during a phase change.

Calorimetry

is the measurement of heat changes during a chemical reaction.

Enthalpy of vaporization

is how much energy is required to turn a liquid to a gas.

Endothermic reactions

occur when a system absorbs the energy from the surroundings, such as when a beaker feels cold.

Vapor pressure

is the amount of pressure given off by molecules as they go from solid /liquid to gas.

heat of vaporization

The is the energy given off when a gas condenses.

Hydration energy

is a Coulombic energy and its magnitude increases as the ions increase their charge or decrease the size.

released

When bonds are formed, energy is ____.

Enthalpy of fusion

is the amount of energy required to cause a solid to melt.

absorbed

When bonds are broken, energy is _.

Solid to gas

sublimation

Gas to solid

deposition

ΔH

Enthalpy change

ΔHf°

Enthalpy of formation

Enthalpy of formation

The amount of energy released when one mole of a compound is made from pure substances

Vapor pressure

Molecules that go from solid/liquid to gas emit .

Endothermic

is when energy is transferred from the surrounding to the system, such as when a chemical reaction occurs in a beaker and the beaker feels cold.