How many calories does it take to heat 10 grams of 16 degree C water to a vapor?

Question

How many calories does it take to heat 10 grams of 16 degree C water to a vapor?

Answer 1

There are two parts to this problem.

1. calculating the calories needed to heat the water to boiling (100^oC).
2. calculating the calories needed to vaporize the boiling water.

Part 1. It takes 1 calorie to increase the temperature of 1 gram of water one degree centigrade. There are 84 degrees to heat the water from 16^oC to 100^o Centigrade. Therefore, 84 calories are needed to heat 1 gram of water to 100^oC; for 10 grams of water, ten times that amount of calories are needed: 10 x 84 calories = 840 calories.

Part 2. The Heat of Vaporization of water is 540 calories per gram;since we have 10 grams of water to vaporize, we need 5,400 calories for vaporization.

The answer to the problem is the sum of Part 1 and Part 2 = 840 calories + 5,400 calories = 6,240 calories.