Entropy change when heat flows

Answer Key - Grade 11 Science Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   1200 J of heat flows from a hot reservoir at 600 K to a cold one at 300 K. What is the total entropy change, to 0.01 J/K, Bo?

   2 J/K
2. 2.

   900 J of heat flows from a hot reservoir at 450 K to a cold one at 300 K. What is the total entropy change, to 0.01 J/K, Esme?

   1 J/K
3. 3.

   2000 J of heat flows from a hot reservoir at 500 K to a cold one at 250 K. What is the total entropy change, to 0.01 J/K, Jun?

   4 J/K
5. 4.

   In the bar chart, what are the entropy changes of the two reservoirs, Kira?

   • Hot −3 J/K; cold +6 J/K
   • Hot +3 J/K; cold −6 J/K
   • Hot +3 J/K; cold +6 J/K
6. 5.

   In the bar chart, what is the total entropy change, Luz?

   Use the picture in question 4.

   • −3 J/K
   • +3 J/K
   • +9 J/K
7. 6.

   When heat flows from a hot block to a cold one, what happens to the hot block's entropy, Pia?

   • It falls, while the cold block's rises by more
   • It cannot fall, since entropy can't go down
   • It rises, like the cold block's
8. 7.

   A refrigerator moves heat out of its cold inside. Can the inside's entropy fall, Ren?

   • Yes; the room gains more, so the total still rises
   • Yes; and the total entropy falls too
   • No; entropy can't fall in any place
9. 8.

   Ice melts at 273 K. What happens to the entropy of the water, by Tala's reading (OpenStax)?

   • It falls
   • It stays the same, since T is steady
   • It rises
10. 9.

    Water freezes at 273 K, giving heat to the colder freezer air. What happens to the water's entropy, Zee?

    • It falls, while the surroundings gain more
    • It cannot fall, since entropy can't go down
    • It rises, since ice forms
11. 10.

    Why is liquid water more disordered than ice, by Ari's reading (OpenStax)?

    • Its molecules can be arranged in many more ways
    • Its molecules are packed in a fixed pattern
    • It has fewer molecules than the ice