Textbook 4A.7

[Rhea Jain 2I]

(a) Calculate the heat that must be supplied to a copper kettle of mass 400.0 g containing 300.0 g of water to raise its temperature from 20.0°C to the boiling point of water, 100.0°C. (b) What percentage of the heat is used to raise the temperature of the water?

Can someone help me with this problem? I'm not sure how to approach it. Any help would be greatly appreciated!

[Alicia Li 2E]

Hi! For part a, you use the equation q=mc(deltaT). To calculate the amount of heat supplied to the kettle, you find the specific heat capacity of copper (0.38 J/(g*C)) and you input that into the equation. You add that to the amount of heat needed to raise the water to 100C using the specific heat capacity of water (4.184 J/(g*C)). Add these two values together will get you the amount of heat needed. T in this case is 100-20C.
For part b, the percentage of heat is just the heat needed to raise the water's temperature divided by the total temperature needed.