Nitrogen, oxygen and argon are obtained from liquid air. The table shows the melting points and boiling points of these three elements.
| Element | Melting point / °C | Boiling point / °C |
|---|---|---|
| nitrogen | −210 | −196 |
| oxygen | −218 | −183 |
| argon | −189 | −186 |
Give the state of oxygen at −190 °C.
Give the state of nitrogen at −190 °C.
Liquid air is warmed slowly from −200 °C. Give the name of the element that boils first.
Explain, in terms of particles and energy, what happens when liquid nitrogen boils.
Suggest why it is difficult to separate argon from oxygen using their boiling points.
53 exam-style questions on Edexcel GCSE Chemistry 3.1 States of matter, covering 3.1.1 The three states of matter and changes of state. Each one has a worked solution and a mark scheme showing where the marks go.