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amm1812
4 years ago
6

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
Chemistry
2 answers:
stira [4]4 years ago
6 0

Answer:

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

Q1 = 7 kg*2.108 KJ/Kg-K*9K = 132.8 kJ

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

Q2 = 7 kg*334kJ/Kg =2338 kJ

Step 3: Total heat required

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

notka56 [123]4 years ago
3 0
The answer to this question is D
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