A sealed cylindrical actuator contains 0.84 kg of a pure substance, R. Heating R makes a sliding end of the actuator move outwards.
The table gives the density of R in each state under the conditions of the test.
| State | Density in kg/m3\text{kg/m}^{3}kg/m3 |
|---|---|
| solid | 840 |
| liquid | 760 |
| gas | 2.8 |
The internal radius of the actuator is 0.25 m and its maximum internal length is 1.40 m.
The actuator stands on a balance. Before R is heated, the balance reads 45.0 kg.
A technician claims that the density decreases when R changes from a liquid to a gas because each particle becomes lighter.
Explain the change in density and the reading shown by the balance after all of R becomes a gas.
A small piece of solid R is placed in liquid R.
Explain whether the solid piece sinks or floats.
Calculate whether the maximum internal length of the actuator is enough to contain all of R as a gas.
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.