Question

How much heat is given off by 1,000 kg of iron when it solidifies
at its melting point?
A. 2.66 x 10^8 J

B. 3.76 x 10^-3 J

C. 2.66 x 10^2 J

D. 2.66 x 10^7 J

Answer 1

A. 2.66 x 10^8 J

Explanation:

We are given the heat of fusion of iron to be $2.66 \times 10^5$ and it it in $J/kg$ so in order to find the amount of heat given off, we multiply the Heat of Fusion by the number of kilograms of Iron(1000 kg).

Solving:

$Q = \text{Mass} \times \text{Heat of fusion}\\Q = 1000 \, \text{kg} \times 2.66 \times 10^5 \, \text{J/kg}\\\boxed{Q = 2.66 \times 10^8 \, \text{J}}$

Therefore, A is the correct answer!