How much heat energy (in megajoules) is needed to convert 7 kilograms of ice at -9 degrees celsius to water at 0 degrees celsius? a. 3.09 mj b. 2.48mj c. 3.26 mj d. 2.13mj

B 2.48 mJ

Explanation:

The process can be broken into 2 steps

Step1: Heat required to raise the temperature of ice from -9 to 0 C

Q 1 = mcΔT

where m = mass of ice = 7 kg

c = specific heat capacity of ice = 2.108 kJ/kg-K

ΔT = T2-T1 = (273 - 264)K = 9 K

Step 2: Heat required for phase transition from ice at 0 C to water at 0C

Q 2= m*ΔH(fusion)

where ΔH(fusion) is the latent heat of fusion of ice = 334 kJ/Kg

Step 3: Total heat required

Q = Q1 + Q2 = 132.8+2338 = 2470.8 kJ ≅ 2.48 Mj