Relative formula mass (Edexcel GCSE Chemistry & Combined Science)

This lesson describes how to calculate the relative formula mass from simple chemical formulae and for those that include brackets. The PowerPoint and the accompanying worksheet have been designed to cover point 1.43 of the Edexcel GCSE Chemistry specification and also covers that point in the Chemistry section of the Combined Science course.

The lesson contains a wide range of tasks, understanding checks and quick quiz competitions to guide students through calculating the relative formula mass for substances with a range of chemical formulae. The relative formula mass is required in a lot of calculations, such as those that involve moles, so it is an important skill to get right. Worked examples are used throughout the lesson to visualise the metho for the students. Initially, students will learn how to calculate the mass from simple formulae before helpful hints are provided for harder formulae such as those that contain a bracket. Students are given the chance to apply their knowledge by proving that mass is conserved in a reaction and this prepares them for an upcoming lesson.

This lesson has been written for GCSE students but could be used with higher ability KS3 students in lessons that are looking to push knowledge forward