## 4A.7

kanikubari
Posts: 30
Joined: Fri Dec 07, 2018 12:18 am

### 4A.7

What is the equation we use for this problem? Also when I checked the solutions manual, why were the grams multiplied by (4.18 J) and (0.38J)?

Iona Pay
Posts: 43
Joined: Fri Sep 28, 2018 12:15 am

### Re: 4A.7

Assuming this is for the 7th edition here. For anyone who's also having difficulty with this problem and doesn't have the book around, the problem reads:

A. Calculate the heat that must be supplied to a copper kettle of mass 400.00 g containing 300.00 g water to raise its temperature from 20C to 100C, the boiling point of water.

B. What percentage of the heat is used to raise the temperature of the water?

In this problem, we are trying to calculate the amount of heat it takes to raise the copper vessel's temperature 80 degrees, and the amount of heat it takes to raise the water inside it 80C. To find this value, we should use q = (mass of substance)(heat capacity of substance)(temperature change) for each, then add them together. The values 4.18 J/C*g and .38 J/C*g are the heat capacities of water and copper respectively.