Magnesium is heated strongly in oxygen and a white powder forms. A student compares particle models of the substances before and after heating. Which result explains the student's conclusion that a chemical change has occurred?
The particles have moved more slowly during the change
The particles have become more closely packed during the change
The atoms have increased in size during the change
The atoms have rearranged to make different particles during the change
93 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.