Question

What is the total heat needed to change 1g of water from -10°C to 110°C at 1 atm? \[ \Delta H_{fusion} = 80 \, \text{cal/g}, \Delta H_{vaporisation} = 540 \, \text{cal/g}, \text{specific heat of ice and steam are 0.5 cal/g°C} \]

• A. -730 cal
• B. -630 cal
• C. 630 cal
• D. 730 cal

Hint:

Remember to account for the different phases (solid, liquid, gas) and use the appropriate heat of fusion or vaporisation.

Answer 1

The Correct Option is D

The total heat is the sum of the heat required to raise the temperature of ice, melt it, raise the temperature of water, and then vaporise it.