Welcome to the Heat and Enthalpy debriefing

Answer the questions below, and click on the Check buttons when you are ready.


Sublimation is a phase change in which a solid changes directly to a gas without passing through the liquid state. At low temperatures, this will happen to water (this is how a frostfree refrigerator works).

1. How much solid H2O can be sublimed with 1.06 kJ of heat? The DHsub of H2O at 0 ºC is 2.8 kJ/g.

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Answer:


Correct! 0.38 g of solid water can be sublimed at 0 ºC by that much heat.
While numerically correct, your answer has the wrong number of significant digits. Try again.
0.38 g of solid water can be sublimed at 0 ºC by that much heat.
That is incorrect. Please try again.

When a blacksmith has forged iron into the shape of a horseshoe he cools the iron by dropping it into water.

2. If a 1.00 kg horseshoe at 738 ºC is dropped into a 114 L barrel of water at 25.0 ºC, what will be the final temperature of the water and horseshoe?

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Answer:


Correct! Because there is so much water and it has such a high heat capacity compared to the iron in the horseshoe, the temperature of the water rises only a little bit, while the iron is cooled enough to be able to be touched.
While numerically correct, your answer has the wrong number of significant digits. Try again.
Because there is so much water and it has such a high heat capacity compared to the iron in the horseshoe, the temperature of the water rises only a little bit, while the iron is cooled enough to be able to be touched.
That is incorrect. Please try again.

Congratulations!

You have completed the Heat and Enthalpy module.

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