Question

1. A kettle uses 167200J of heat energy when it heats water from 20⁰C to 100⁰C.  How much water is in the kettle? The specific heat capacity of water is 4180j/kg⁰C.

1. The temperature of a 0.8 kg metal block is raised from 27 °C to 77 °C when 4200 J of energy is supplied.  Find the specific heat capacity of the metal.

1. 9600 J of heat energy is supplied to 1 kg of methylated spirit in a polystyrene cup.

Calculate the rise in temperature produced.

Take the specific heat capacity of methylated spirit to be 2300 J/kg°C.

1. A 750g steel cooking pan cools from 65⁰C to 18⁰C.  How much heat energy is released by the pan?  The specific heat capacity of steel is 500j/kg⁰C.

1. An insulated container contains 0.5kg of water at an initial temperature of 16⁰C.  A heater is placed in the water and switched on.  It supplies 83600J to the water.  Calculate the final temperature of the water.  (Specific heat capacity of water = 4180J/kg⁰C)

Answer 1

1.

$m=\frac{Q}{c(t_2-t_1)}=0.5~kg.$

2.

$c=\frac{Q}{m(t_2-t_1)}=105~\frac{J}{kg\cdot °C}.$

3.

$\Delta t=\frac{Q}{mc}=4°C.$

4.

$Q=cm(t_2-t_1)=17625~J.$

5.

$t_2=t_1+\frac{Q}{cm}=56°C.$