The passage below is about kinetic theory.
Complete the sentences.
Molecules in a gas are in constant random motion at ............... speeds.
Random motion means that the molecules do not travel in a specific path and undergo sudden changes in their motion if they collide with the ............... of its container or with other ................. .
The ................ of the gas is related to the average kinetic energy of the molecules.
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A sealed boiling tube as shown in Figure 2 contains some gas.
The boiling tube is heated.
Figure 2
State what happens to the particles of gas as the temperature increases.
The boiling tube is then placed in an ice bath.
State what happens to the speed and the kinetic energy of the particles in the gas.
On the axes below, sketch a graph of pressure against temperature for a constant volume of gas. Clearly mark the value of absolute zero on your graph.
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Figure 1 shows some gas particles in a container.
The piston can be moved in or out to change the volume of the gas.
Figure 1
Add arrows to the diagram to show the motion of the gas particles.
Explain how the motion of the gas particles produces a pressure inside the container.
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Using ideas about particles, explain how air inside a container exerts pressure.
The air in the tyre heats up when the car is driven.
Explain how this affects the contact between the tyre and the ground.
You should assume that the volume of the air remains constant.
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Figure 3 below shows the basic details of the steam engine used in a steam locomotive.
Figure 3
The following is a description of how the steam engine works:
Explain why the pressure of the steam increases as its temperature increases.
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Figure 4 shows the particles of helium inside a balloon.
Figure 4
Describe the motion of particles inside the helium balloon
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A student wants to investigate gas pressure. They blow up two balloons to the same size.
They put one balloon into a freezer.
After a while, the student compares the two balloons and finds that the balloon that has been cooled is smaller.
Explain why the cooled balloon is smaller using ideas about particles.
The student decides to investigate the link between temperature and the size of the balloon.
They write a plan for this experiment:
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I will change the temperature of the balloon by putting it into a freezer. To get a range of different temperatures I will put the balloon into the freezer for different times. I will measure the temperature of the balloon using a thermometer. To measure the size of the balloon I will take it out of the freezer and line it up next to a ruler. To make sure it is a fair test I will repeat the experiment three times. I will plot a graph of size against temperature. |
There are several faults in the student's plan.
Identify three of these faults and suggest an improvement to correct each one.
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Figure 1 is a graph showing how the volume changes with pressure for a gas at a constant temperature.
Figure 1
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