A fixed quantity of gas is trapped in a sealed syringe. No molecules enter or leave the syringe. The plunger is pushed in so that the volume of the gas decreases by a factor of four. Which statement compares the gas before and after the plunger is moved?
Its density is four times as great, and its mass is unchanged.
Its density is unchanged, and its mass is one quarter as great.
Its density is one quarter as great, and its mass is unchanged.
Its density is unchanged, and its mass is four times as great.
87 exam-style questions on Edexcel GCSE Physics 14.1 Density and states of matter, covering 14.1.1 Kinetic theory and states of matter, 14.1.2 Density, and 14.1.3 Density and changes of state. Each one has a worked solution and a mark scheme showing where the marks go.