ch. heat numerical 8

Asked by nilesh.dhote74 | 13th Jul, 2020, 12:38: PM

Expert Answer:

Let whole of the ice melts and let the final temperature of the mixture be ToC.

Amount of heat energy gained by 10g of ice at -10oC to raise its temperature to 0oC= 10x10x2.1=210J

Amount of heat energy gained by 10g of ice at 0oC to convert into water at 0oC=10x336=3360 J

Amount of heat energy gained by 10g of water (obtained from ice) at 0oC to raise its temperature to ToC = 10x4.2x(T-0)=42T

 

Amount of heat energy released by 10g of water at 10oC to lower its temperature to ToC = 10x4.2x(10-T)=420-42T

 

Heat energy gained = Heat energy lost

210 + 3360 + 42T = 420-42T

T = -37.5oC

This cannot be true because water cannot exist at this temperature.

 So whole of the ice does not melt. Let m gm of ice melts. The final temperature of the mixture becomes 0oC.

 So, amount of heat energy gained by 10g of ice at -10oC to raise its temperature to 0oC= 10x10x2.1=210J

Amount of heat energy gained by m gm of ice at 0oC to convert into water at 0oC=mx336=336m J

 Amount of heat energy released by 10g of water at 10oC to lower its temperature to 0oC = 10x4.2x(10-0)=420

Heat energy gained = Heat energy lost

210 + 336m = 420

m = 0.625 gm

 

Answered by Shiwani Sawant | 13th Jul, 2020, 01:30: PM