Calculate the amount of heat needed to melt 145.g of ice ( H2O ) and bring it to a temperature of 42.8°C .

Question

Calculate the amount of heat needed to melt
145.g of ice (H2O) and bring it to a temperature of
42.8°C Round your answer to
3
significant digits. Also, be sure your answer contains a unit symbol.

Answer 1

You will need to know the heart of fusion of ice. According to the textbook, the molar heat of fusion for water is 6.01 kJ/mol. Let's use this one. 

First you calculate heat of fusion of 145. g ice. Once it becomes water at 0°C, you will calculate the heat when the temperature of water rises from 0 degree to 42.8 degree. Then you add these two, it will be the answer. 

 

q1 = 6.01/18 *145 =48.4 kJ

q2 = cm(delta T) = 4.18*145*42.8 = 25941 J =25.941 kJ, round it to 3 Sig Fig, q2 = 25.9 kJ

 

q1+q2 = 48.4 + 25.9 =74.3 kJ