7.2

Question 1

Free energy (Gibbs free energy)

Answer 1

G=H-TS
G= energy available to do work
H= enthalpy (energy in a molecules chemical bonds)
T= absolute temperature (k)
S= entropy

Question 2

Delta G

Answer 2

Change in free energy
Delta G= Delta H- TdeltaS

Question 3

Positive Delta G reactions require energy to proceed

Answer 3

Products have more free energy than reactants, i.e., products have a higher H or lower S (or both)
Not spontaneous -endergonic
Delta G > 0

Question 4

Negative delta G reactions tend to occur spontaneously

Answer 4

Products have less free energy than reactants i.e. products have lower H or higher S (or both)
Spontaneous- termed exergonic
Delta G < 0

Question 5

Activation energy

Answer 5

Extra energy required to destabilize existing bonds and initiate a chemical reaction
Larger activation energy= slower reaction rate

Question 6

To increase reaction rate either

Answer 6

1. Increase energy of reacting molecules (heating)
   Or
2. Use a catalyst to lower activation energy

Question 7

Catalysts

Answer 7

-Substances that influence chemical bonds in a way that lowers activation energy of a reaction
-Cannon violate laws of thermodynamics
- do not alter the proportion of reactant turned into product