Iodine is a grey-black solid.
A student warms some iodine gently in a sealed tube. A purple gas forms. When the tube cools, grey-black crystals of iodine form again on the cool part of the tube.
Is the change from solid iodine to purple iodine gas a physical change or a chemical change?
Explain your answer in terms of particles.
Zinc powder reacts with iodine to make zinc iodide, a white solid.
Complete the word equation for this reaction.
zinc + iodine →\rightarrow→ ......
Explain, in terms of particles, why the reaction of zinc with iodine is a chemical change.
The student measures the mass of the sealed tube of iodine before warming and after warming.
State what happens to the mass. Explain your answer in terms of particles.
48 exam-style questions on OCR GCSE Chemistry 1.1 The particle model, covering 1.1.1 The particle model and changes of state and 1.1.2 Limitations of the particle model. Each one has a worked solution and a mark scheme showing where the marks go.