Particles, temperature and gases — GCSE Physics practice questions

Question 1

A football is pumped full of air.

Which row describes the properties of the air inside the ball?

Accepted Answer

A: no · no · yes. Air is a gas. A gas takes the shape of its container and spreads out to fill all of it, so it has neither a fixed shape nor a fixed volume. Its particles are far apart, so it is easily compressed — which is why the ball can be pumped up with more air.

Question 2

A pizza oven is lit. Its temperature rises from 20 °C to 420 °C.

What is the rise in temperature in kelvin?

Accepted Answer

B: 400 K. The kelvin and the degree Celsius are the same size, so a rise of 400 °C is a rise of 400 K. Converting both values first gives the same result: 693 K − 293 K = 400 K.

Question 3

In a workshop, a small aluminium block P of mass 0.50 kg at 80 °C is clamped against a large aluminium block Q of mass 2.0 kg at 50 °C. The blocks are wrapped in insulation.

Which statement is correct?

Accepted Answer

A: Energy is transferred from P to Q, because the particles of P have the greater average kinetic energy.. P is hotter, so its particles have the greater average kinetic energy, and energy is transferred from P to Q. The transfer stops when both are at the same temperature, not when they have the same internal energy: at that point Q, with four times the mass, still stores more. Because Q has more mass of the same metal, the final temperature is close to Q's: 0.50 × (80 − θ) = 2.0 × (θ − 50) gives θ = 56 °C, not 65 °C.

	fixed shape	fixed volume	easily compressed
A	no	no	yes
B	no	yes	no
C	no	yes	yes
D	yes	yes	no