REVIEW & REHEARSE: 4 ENERGY
<i>Check Your Knowledge</i>
Question 4.17
Animal fats and plant oils are sometimes used as sources of fuel for automobile engines. How is energy harvested from these molecules?
- a) They contain long chains of hydrogen and carbon that, when broken, release the energy stored in the bonds linking the atoms together.
- b) They contain hydrogen and carbon tails linked by covalent bonds that, when broken, release chemical energy.
- c) They contain multiple phosphate groups that each release energy when “liberated” from the molecule chemically.
- d) They contain long hydrophobic regions that, when mixed with water, generate explosive resistances.
- e) They contain long carbon tails, and each atom has unpaired electrons that are released on exposure to extreme heat and pressure.
Question 4.18
A cyclist rides her bike up a very steep hill. Which of the following statements properly describes this activity in energetic terms?
- a) Potential energy in food is converted to kinetic energy as the cyclist’s muscles push her up the hill.
- b) Kinetic energy is highest when the cyclist is at the crest of the hill.
- c) The cyclist produces the most potential energy as she cruises down the hill’s steep slope.
- d) Potential energy is greatest when the cyclist is at the top of the hill.
- e) Both a) and d) are correct.
Question 4.19
Every time a source of energy is converted from one form to another:
- a) the potential energy of the system increases.
- b) heat is required.
- c) the second law of thermodynamics is violated.
- d) the total amount of energy in the universe is reduced by a tiny amount.
- e) some of the energy is converted to heat, which is not a very usable form of kinetic energy.
