CM011 - Thermochemistry

Formulas

Thermochemistry

The study of heat energy.

Radiant energy

Energy that comes from the sun; Earth’s primary energy source

Thermal Energy

Energy associated with the random motion of atoms and molecules.

Chemical Energy

Energy stored within the bond of chemical substances.

Nuclear energy

Energy stored within the collection of neutrons and protons in the atom.

Potential Energy

Energy stored within the collection of neutrons and protons in the atom.

Exothermic Process

Gives off heat; transfers thermal energy from system to surroundings.

Endothermic Process

Heat has to be supplied to the system from the surroundings

Thermodynamics

The study of intervention of heat and other kinds of energy

State Functions

Properties that are determined by the state of the system, regardless of how that condition was achieved.

ΔU = U_f - U_i

ΔV = V_f - Vi

ΔT = T_f - T_i

PΔV = nRT

First Law of Thermodynamics

Energy can be converted from one form to another, but cannot be created or destroyed.

ΔU_system + ΔU_surroundings = 0

ΔU_system = q + w

Work done by the System on the Surrounding

w = -P ΔV

Conversion factor between L·atm and J

101.3 J / 1

Enthalphy

Used to quantify the heat flow in or out of the system in a process that occurs at constant pressure.

ΔH

ΔH = H_products - H_reactants

ΔH>0, system absorbs heat

Endothermic

ΔH<0, system gives off heat

Exothermic

Specific Heat (s)

The amount of heat (q) required to raise one gram of the substance by one degree Celsius.

Heat Capacity (C)

The amount of heat (q) required to raise the temperature of a given quantity (m) of the substance by one degree Celsius.

Heat Capacity (C)

C =

Heat (q)

q = msΔt

q = CΔt

Entropy (S)

The measure of how spread out or how dispersed the system’s energy is.