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Calculate the quantity of heat needed to change the tempe...

Calculate the quantity of heat needed to change the temperature of 60g of ice at 0 °C to 80 °C. [specific latent heat of fusion of ice= 3.36 x 105 Jkg1 specific heat capacity of water 4.2 x 103 J kg1 K1]


 

A.

4.80 kJ

B.

20.16 kJ

C.

40.32 kJ

D.

22.17 kJ

Correct answer is C

Heat needed to change 60g (0.06kg) of ice at 0oC to water at 0o 

 = 0.06 x 3.36 x 105J

= 0.2016 x 105 J

Heat required to raise the temp. of 60g (0.06kg) of water from 0oC to 80oC

= 0.06 x 4.2 x 103 x (80.0)J 

= 0.06 x 4.2 x 103 x 80 

= 20.16 x 103 

= 0.2016 x 105 

Total heat needed = (0.2016 + 0.2016) 105J

= 0.4032 x 105 J

= 40.32KJ