The calories needed to change 10 grams of ice at 0°C to steam at 100°C is
A)6200.
B)6400.
C)7200.
D)8000.
E)none of the above

Question

Quizplus · Accepted Answer

The process consists of three steps: 
1. Heating the ice from 0°C to 0°C water (10 g x 80 cal/g = 800 cal) 
2. Melting 10 grams of ice at 0°C (10 g x 80 cal/g = 800 cal) 
3. Heating the water from 0°C to 100°C (10 g x 100 cal/g = 1000 cal) 
4. Vaporizing the water into steam at 100°C (10 g x 540 cal/g = 5400 cal)

Adding up the calories needed for each step gives a total of 7200 calories. Therefore, the correct answer is C.

The Calories Needed to Change 10 Grams of Ice at 0°C