How much heat is necessary to change 10 g of ice at -10°C into water at 20°C?
A) 0.025 kcal
B) 0.25 kcal
C) 1.05 kcal
D) 0.095 kcal

Question

Quizplus · Accepted Answer

To solve this problem, we need to calculate the heat required to melt the ice (heat of fusion) and to heat the resulting water from -10°C to 20°C (specific heat).

1. Heat required to melt the ice: 
Q = m × ΔHfus 
Q = 10 g × 80 cal/g 
Q = 800 cal

2. Heat required to heat the resulting water: 
Q = m × Cp × ΔT 
Q = 10 g × 1 cal/g°C × (20°C - (-10°C)) 
Q = 10 g × 1 cal/g°C × 30°C 
Q = 300 cal

Total heat required: 
Qtotal = Q1 + Q2 
Qtotal = 800 cal + 300 cal 
Qtotal = 1100 cal

Converting to kcal: 
Qtotal = 1.1 kcal

Therefore, the answer is C) 1.05 kcal.

How Much Heat Is Necessary to Change 10 G of Ice