Thermochemistry

Thermochemistry is the study of heat and its relation to chemical reactions.

Thermochemistry Vocabulary

exothermic: a change that releases heat (i.e. combustion reactions)

endothermic: a change that absorbs heat (i.e. icy-hot or a cold pack)

enthalpy (H): sum of internal energy

Change of enthalpy (ΔH): final enthalpy minus initial enthalpy. Note that changes in enthalpy are additive; which is known as Hess's law.

• ΔH <0: exothermic

• ΔH > 0: endothermic

Heat (q): the thermal energy that is transferred from one object to another. When pressure is constant, heat and change in enthalpy are equal.

Important Equations

m is the mass, C is the specific heat, and ΔT is the change in temperature

Problem Solving with Enthalpy (~3 min)

A Commone Hess's Law Question (3:10)

Calorimetry Examples (4:13)

Math Resources 

Below are some potentially useful math resources for this chapter. Click on the names of the sections to view the resources.

Units and Dimensional Analysis

Order of Operations

Solving Equations

Calculators