Question

a student redid the experiment of mixing room-temperature water and warm water. this time, she doubled the amount of warm water. how will the final temperature be different?

a. it will be higher, because the amount of water in the mixture is greater.

b. it will be the same, because all parts of the mixture will end up at the same temperature.

c. it will be higher, because the warm water will transfer more thermal energy to the room-temperature water.

d. it will be lower, because the room-temperature water will absorb more thermal energy from the warm water.

Explanation:

• Option A: The final temperature of a mixture of two substances (here, water at different temperatures) depends on the thermal energy transfer, not just the total amount of water. So this is incorrect.
• Option B: While the mixture will have a uniform temperature, doubling the amount of warm water (which has more thermal energy) will change the final temperature. So this is incorrect.
• Option C: Warm water has higher thermal energy than room - temperature water. When we double the amount of warm water, there is more thermal energy available to be transferred to the room - temperature water. This will result in a higher final temperature of the mixture. This option is correct.
• Option D: If the room - temperature water absorbs more thermal energy from the warm water, the final temperature should be higher, not lower. So this is incorrect.

Answer:

C. It will be higher, because the warm water will transfer more thermal energy to the room - temperature water.