16.1 Thermo Review + Spontaneity

Energy is neither created nor destroyed

First law of thermodynamics

∆E = q + w → ∆E = ∆H + P∆V

This function is a _____ function, meaning it depends only on the _____ and ______ states of the system, not on the ______ taken.

Change in energy of a system is equal to the heat released (q) and the work done by the system (w). It is related to the enthalpy / H (heat absorbed or released during a reaction) plus the pressure-volume work (P∆V)

Ans: state, initial, final, path

Determined by comparing the free energy of the system before vs. free energy of the system after the reaction

Spontaneity

When there is less free energy after a reaction, it is called “______________”

thermodynamically favorable

A spontaneous process is dependent on _________ and _________. This relationship is represented by the equation ______________.

enthalpy (H), entropy (S), ∆G = ∆H - T∆S (where G is Gibbs free energy and T is temperature in K)

Enthalpy is related to _____ energy (the _____ and _____ of _____ during a reaction)

bond, breaking, forming, bonds

What can H tell us about a reaction? What are its units?

Determines whether a reaction is exothermic (products favored, ∆H < 0) or endothermic (reactants favored, ∆H > 0). Units: kJ/mol

According to Le Chatelier’s principle, ______ reactions are favored by lower temperatures, while _______ reactions are favored by higher temperatures.

exothermic, endothermic