14.1 States of Matter & Thermal Capacity

An electric kettle contains 1.41 kg of water at 25°C.

The kettle is switched on.

After a while, the water reaches boiling point at 100°C.

The specific heat capacity of water is 4200 J/ kg°C.

[3]

energy supplied = .............................................................. J

[3]

specific latent heat of vaporisation = .............................................................. J/ kg

Figure 21

The piece of string is tied to the aluminium block so the block can be transferred
from the boiling water to the cold water.

Describe how a student could use this apparatus, and any additional items
needed, to determine the specific heat capacity of aluminium.

Your answer should include how the student would

• obtain the necessary measurements
• use the measurements to calculate the specific heat capacity of aluminium.

A student investigates the density of a brick and the density of a small toy, as shown in Figure 1.

Figure 1

The student found the volume of the brick by multiplying the area of its base by its height. The fish toy does not have straight sides.

Describe how the student could measure the volume of the small toy.

You may use a diagram if it helps your answer.

The student uses the equipment shown in Figure 2 to measure the temperature of water as it is heated.

Figure 2

Describe an experiment the student could carry out to determine the specific heat capacity of the water.

A student measures the density of glass.

The student has

− a bag of marbles, all made from the same type of glass
− a weighing balance
− a plastic measuring cylinder containing water

Describe how the student could find, as accurately as possible, the density of the glass used for the marbles.

A beaker contains 0.25kg of water at room temperature.

The beaker of water is heated until the water reaches boiling point (100°C).

The specific heat capacity of water is 4200 J/kg°C.

The total amount of thermal energy supplied to the water is 84 000J.

Figure 13

Describe how the density of water changes with temperature over the range of temperature shown in Figure 13.

Calculations are not required.

A student determines the density of a liquid.

The student puts an empty measuring cylinder on a balance (Figure 10a).

The student then adds liquid to the measuring cylinder (Figure 10b).

Calculate the mass of liquid added and the volume of liquid added.

Use the information in Figures 10a and 10b.

Determine 

[1]

[1]

	☐	A	density = mass + volume
	☐	B	density = mass - volume
	☐	C	density = mass × volume
	☐	D

The kettle contains 1.5kg of water.

The kettle is switched on.

Calculate the energy needed to raise the temperature of the water by 50 °C.

Specific heat capacity of water = 4200 J/kg°C

Use the equation

[2]

energy needed = ............................................... J

Water vapour is contained in a lidded beaker.

Describe the movement of the particles in:

As the water vapour cools, the temperature is taken at regular intervals.

Sketch a graph to show the change in temperature with time.

Explain what is meant by the specific heat capacity of a substance.

A mass of 170 g of water is needed to make a cup of coffee which is brewed at an optimum temperature of 80 ºC. The water is heated in a kettle from a temperature of 55 ºC from the tap.

The specific heat capacity of water = 4200 J kg¹ K¹.

Calculate the energy needed to boil the water.