Ch. 19 Free Energy & Thermodynamics

Question 1

What is a spontaneous change?

Answer 1

a spontaneous change occurs with tendency to occur with NO external factors/forces.

Question 2

What is the difference in spontaneous and nonspontaneous changes?

Answer 2

nonspontaneous changes occur ONLY when driven by external forces.

Question 3

What is Entropy?

Answer 3

Entropy is the disorder/randomness of a reaction VS. the order of a system.

Question 4

What is the 2nd Law of Thermodynamics?

Answer 4

a spontaneous reaction is one that increases the entropy of the universe.

Question 5

What is the 3rd Law of Thermo?

Answer 5

Nothing has an entropy of 0 (S=0) except a perfect crystal at 0 K.

Question 6

How does Entropy change for each physical state? (s,l,g,aq) When does entropy increase?

Answer 6

S(solid)

Question 7

What is entropy HIGHER for?

Answer 7

Higher temperatures, Larger volumes, More complex molecules, Increase in moles of gas, less pressure, heavier atoms, larger sample sizes.

Question 8

What is Gibb’s Free Energy? What is it a function of?

Answer 8

The amount of chemical energy available to do work. It is a function of Temperature.

Question 9

How do K constants (equilibrium, solubility, etc.) relate to ΔrG?

Answer 9

IF K<1 , ΔG is negative (spontaneous! prod favored)

IF K>1 , ΔrG is positive (reactant favored, nonspont.)

Question 10

What is the difference between ΔG and ΔrG?

Answer 10

ΔG is the change in free energy at NON-standard conditions, ΔrG is when pure reactants convert completely to pure products.