Monday, 8 September 2014

Thermal expansion


                               Thermal expansion 



1     Write the following in order of increasing expansion: liquid, gas, solid.

2     Write down three examples of the expansion of a solids.

3     Give two reasons why mercury is used in thermometers.

4     Why is alcohol used in some thermometers?

5 (a)What is a bi-metallic strip?
       Aluminium expands more than   
        copper.
    (b) what wil happen when it is put in a freezer?
                                                                          
6     What happens to the volume of a sample of water when it is frozen?

7     What would you expect the temperature at the bottom of a pond to be if the water at the top of the pond had frozen?

8     (a) a metal washer is heated. What happens to the hole in the centre of the washer?
      (b) What would happen if the piston and cylinder in a car engine were made of metals that expanded by different amounts when heated?

9     What would be the approximate increase in length of a 100 cm long iron rod if it is heated by 500C?

10   Glass is a poor conductor of heat. Why will a hot, thick glass beaker break if put gently but quickly into cold water? Suggest why this does not happen if the beaker is made of:
(a) aluminium;
(b) Pyrex glass.

11   The air in a closed cylinder at a pressure of 50 000 Pa and at 27 oC is heated to 2270C. What is its new pressure?

12   The absolute temperature of the gas in a closed cylinder is reduced to ½ of the original value. What happens to its pressure?

13   A fixed mass of gas has a volume of 4 m3 at 270C and at a pressure of 150 000 Pa. The pressure is now reduced to 100 000 Pa and the volume is decreased at the same time to 0.5                m3. What is the final temperature of the gas?

14   If the temperature of a gas is raised, what happens to the pressure of the gas if its volume stays the same?

15   What is meant by absolute zero?

16   What is the value of absolute zero?

17   What is:
(a) 00C in K; (b) 100o in K?
18   If 4litres of gas at 27oC are heated to 1270C at a constant pressure, what will be the new volume of the gas?

19   What happens to the pressure of the air in a car tyre during a long journey on a hot day?

20 Draw a graph to show:
(a) how the volume of a gas changes if it is heated at a constant pressure
(b) how the pressure of a gas changes if it is heated at constant volume
(c) how the pressure of a gas changes if it is expanded at a constant temperature