Potential, Kinetic, Free, and Activation Energy

Review Questions

Consider a pendulum swinging. Which type(s) of energy is/are associated with the pendulum in the following instances: i. the moment at which it completes one cycle, just before it begins to fall back towards the other end, ii. the moment that it is in the middle between the two ends, iii. just before it reaches the end of one cycle (just before instant i.).

  1. i. potential and kinetic, ii. potential and kinetic, iii. kinetic
  2. i. potential, ii. potential and kinetic, iii. potential and kinetic
  3. i. potential, ii. kinetic, iii. potential and kinetic
  4. i. potential and kinetic, ii. kinetic iii. kinetic

Hint:

C

Which of the following comparisons or contrasts between endergonic and exergonic reactions is false?

  1. Endergonic reactions have a positive ∆G and exergonic reactions have a negative ∆G
  2. Endergonic reactions consume energy and exergonic reactions release energy
  3. Both endergonic and exergonic reactions require a small amount of energy to overcome an activation barrier
  4. Endergonic reactions take place slowly and exergonic reactions take place quickly

Hint:

D

Which of the following is the best way to judge the relative activation energies between two given chemical reactions?

  1. Compare the ∆G values between the two reactions
  2. Compare their reaction rates
  3. Compare their ideal environmental conditions
  4. Compare the spontaneity between the two reactions

Hint:

B