Question

Calculate the heat change at 100C in each of the following problems.Indicate whether heat was absorbed or released.
a. calories to condense 10.0 g of steam
b. kilocalories to condense 75g of steam
c. kilocalories to vaporize 44 g of water.

Answer 1

a.
q = mass steam x delta Hvap.
b.
see a. Convert to kcal.
c.
mass H2O x deltaH vap. Convert to kcal.

Answer 2

a. 12

Answer 3

First you multiply 10.0 with 540cal/1 g of H2O.

To calculate the amount of heat added to (or removed from) a sample of water, the mass of the sample is mulitipled by the heat of vaporization, which is 2260. As before, no temperature change occurs during a change of state.

the answer for a will be 5400