Thermodynamics

Enthalpy, Entropy, and Gibbs Free Energy

Temperature

$\Delta$T, average kinetic energy of all particles in matter

Heat

Q, total amount of energy contained in a sample matter

Specific Heat

C_p, amount of heat required to raise the temperature of 1 gram of substance by one degree Celsius

Specific Heat Equation

Q=mC_p$\Delta$T

Enthalpy

$\Delta$ H, the energy absorbed or released during a chemical reaction

Exothermic reaction

-ΔH, Reactions which release heat, hot, heat is a product

Endothermic reaction

+ΔH, Reactions which absorb heat, cold, heat is a reactant

Hess’s law

overall enthalpy charge in a reaction is equal to the sum of the enthalpy changes for the individual steps in the process

Entropy

$\Delta$S, the dispersion of energy or particles

positive entropy value

+ΔS, increased entropy, increase temperature, decreased pressure, increased dispersion

negative entropy value

-ΔS, decreased entropy, decreased temperature, increased pressure, decreased dispersion

entropy comparison

state of matter > complexity > energy level

entropy state of matter comparison

gas > aqueous > liquid > solid

Gibbs Free Energy

$\Delta$G, predicts if a reaction is thermodynamically favorable or not

Thermodynamically Favorable

-ΔG, reaction which can occur without additional energy

Thermodynamically Unfavorable

+ΔG, reaction which requires the input of additional energy

Gibbs Free Energy Equation

$\Delta$G=$\Delta$H - (T$\Delta$S)

primary function of a catalyst reaction

increases reaction rate without being consumes

how a catalyst speeds a reaction

it provides an alternative pathway with a lower activation energy