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igcse physics notesprinted 76 · PDF 76
124 pagesrevision 46936
printed 76 · PDF 76
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Practice Questions (Solved )
Q1. A sealed gas container has a fixed volume. Explain why the pressure of the
gas inside the container increases when it is heated.
Ans) In a gas, particles move randomly and collide with each other and the walls of the
container. The pressure of a gas is caused by the force of these collisions against the
container walls per unit area.
When the temperature of the gas is increased, the particles gain kinetic energy, which
causes them to move faster. Faster moving particles collide with the walls more
frequently and with greater force. Since the container has a fixed volume, the number of
particles remains constant, but the increased frequency and force of collisions lead to a
higher pressure
Q2. Explain why a gas can be compressed more easily than a liquid or a solid.
Ans) In a gas, particles are widely spaced apart and have negligible intermolecular
forces, allowing them to move freely and fill the entire volume of a container. Because
there is a lot of empty space between gas particles, they can be brought closer
together, making gases highly compressible.
Practice Questions ( Unsolved)
P4
1. Explain why solids have a definite shape and volume, while liquids have a definite
volume but no definite shape. What allows gases to have neither a definite shape nor
volume?
2. Describe the changes in particle arrangement and energy when a solid is heated until
it becomes a liquid, then further heated until it becomes a gas. Include details on the
role of intermolecular forces in each state.
3. A balloon is filled with gas at room temperature. Predict what would happen to the
size of the balloon if it were placed in a freezer, assuming the balloon is flexible.