Y9 - Thermal Processes

The table below describes the conditions of the molecules of a substance in each of the three states of matter, solid, liquid and gas.

In your answer write, in a consecutive order, the state of the substance that is described in the left-hand column. (What would you put In the right-hand column). [2 points]

What is the state of matter just before a substance boils? [1 point]

Describe what happens to the molecules during boiling. [2 points]

State two differences between boiling and evaporating. [2 points]

What is the state of matter just before a substance melts? [1 point]

Aluminium melts at 660 °C. At what temperature does it freeze? [1]

The thermometer in Fig. 2.1 is calibrated at two fixed points, and the space between these is divided into equal divisions.

A thermometer is being calibrated with the Celsius scale.

a) Write down another name for the lower fixed point.

b) How is this temperature achieved?

c) What is the temperature of this fixed point? [4 points]

A block of copper and a block of aluminium have identical masses. They both start at room temperature and are given equal quantities of heat. When the heating is stopped, the aluminium has a lower temperature than the copper. Fill in the missing words in the sentence below, to explain this temperature difference.

The aluminium block has a smaller temperature rise than the copper block because the aluminium block has a larger __________________ than the copper block. [1 point]

For strength, concrete pillars are usually reinforced with metal rods, which are embedded in the concrete before it sets. The list below shows how much a length of 1 m of each material expands when the temperature rises by 1 °C.

aluminium - 0.03 mm

concrete - 0.01 mm

steel - 0.01 mm

Use this information to decide:

a) which metal should be used to reinforce concrete

b) why it is suitable

c) why the other metal is not suitable. [3 points]

State what is meant by specific heat capacity. [2 points]