Molecules escape from a liquid during evaporation. The temperature of the remaining liquid changes. Which molecules escape and how does the temperature change?

Small smoke particles suspended in air are viewed through a microscope. The smoke particles move randomly. What does this show?

An engineer wants to fix a steel washer on to a steel rod. The rod is just too big to fit into the hole of the washer. How can the engineer fit the washer on to the rod?

Which two beakers should she use to check the fixed points?

A substance loses thermal energy (heat) to the surroundings at a steady rate. The graph shows how the temperature of the substance changes with time. What could the portion PQ of the graph represent?

The diagrams show four blocks of steel. The blocks are all drawn to the same scale. The same quantity of thermal energy (heat) is given to each block. Which block shows the greatest rise in temperature?

The diagrams represent the molecules in two different states of matter. The arrows show the motion of the molecules. What is state 1, and what is state 2?

The diagram represents moving gas molecules in a sealed container of fixed volume. The temperature of the gas is now increased. What happens to the pressure of the gas, and what happens to the speed of the gas molecules?

A gas is stored in a sealed container of constant volume. The temperature of the gas increases. This causes the pressure of the gas to increase. What happens to the kinetic energy of the gas molecules during this pressure increase?

A car tyre has a constant volume. Why does the pressure of the air in the tyre increase when its temperature increases?

A cup contains hot liquid. Some of the liquid evaporates. What happens to the mass and what happens to the weight of the liquid in the cup?

Why are the cables left loose?

Between which labelled points on the graph is the substance partly solid and partly liquid?