Dry ice is solid carbon dioxide. It is used to keep ice cream frozen during delivery. At normal atmospheric pressure, dry ice changes directly from a solid into a gas at −78 °C.
Name the change of state when a solid changes directly into a gas.
Compare the arrangement and movement of the particles in solid carbon dioxide with those in carbon dioxide gas.
Predict the state of carbon dioxide at normal atmospheric pressure at:
−90 °C
20 °C
Explain why dry ice takes in energy from its surroundings as it changes into a gas, and why this keeps the ice cream cold.
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.