Question

What is the amount of heat to be removed from 2 tons of apples when cooled from 25°C to 5°C? Specific heat of apple is 0.1 kcal/kg°C.

• A. 4000 kcal
• B. 1000 kcal
• C. 2000 kcal
• D. 40,000 kcal

Hint:

Use Q = mass x specific heat x temperature drop, after converting tons to kilograms.

Answer 1

The Correct Option is A

Step 1: The heat to be removed for a simple temperature drop, with no change of state, is found from Q = m x c x deltaT, where m is mass, c is specific heat, and deltaT is the temperature drop.

Step 2: Convert the mass to kilograms. 2 tons of apples equals 2000 kg.

Step 3: Find the temperature drop. The apples cool from 25°C to 5°C, so deltaT = 25 - 5 = 20°C.

Step 4: Put the numbers into the formula: Q = 2000 kg x 0.1 kcal/kg°C x 20°C.

Step 5: Multiply step by step: 2000 x 0.1 = 200, then 200 x 20 = 4000. So Q = 4000 kcal.

Step 6: The other options come from common slips, forgetting to convert tons to kg, using the wrong deltaT, or misplacing a decimal, so the correct value is 4000 kcal.