Question

Latent heat of steam = 536 calories per gm. Latent heat of ice = 80 cal/gm. Specific heat of ice = 0.5 cal/gm degree⁰C. The heat required to convert 10 gm of ice at –20⁰C into steam at 100⁰C is:

• A. 100 calories
• B. 900 calories
• C. 9900 calories
• D. 7260 calories

Answer 1

Answer: (D)

7260 calories

Answer 2

10 ×$\left( \frac{1}{2} \right)$ × 20 + 10 × 80 + 10 × 1 × 100 + 10 × 536

= 100 cal + 800 cal + 1000 cal + 5360

= 7260 cal