The molecules of a gaseous substance become further apart and move more slowly. What is happening to the substance?
The gas is being cooled and compressed.
The gas is being heated and compressed.
The gas is being cooled and is expanding.
The gas is being heated and is expanding.
151 exam-style questions on CIE IGCSE Physics 2.1.2a Particle structure and motion in solids, liquids and gases. Each one has a worked solution and a mark scheme showing where the marks go.