# Relative formula mass (FT only)

This lesson will recap briefly on relative atomic mass and students will calculate relative formula mass and percentage composition of an element in a compound.

# Video

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# Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

Quiz:

# Relative formula mass

This quiz will test your knowledge from this lesson.

Q1.The formula of sodium chloride is NaCl. Calculate the relative formula mass of sodium chloride. Relative atomic masses: Na = 23; Cl = 35.5

1/5

Q2.The formula of magnesium sulfate is MgSO₄. Calculate the relative formula mass of magnesium sulfate. Relative atomic masses: Mg = 24; S= 32; O = 16.

2/5

Q3.Calculate the relative formula mass of iron oxide, Fe₂O₃. Relative atomic masses: O = 16; Fe = 56.

3/5

Q4.A chemist was asked to identify a nitrogen compound. The chemist carried out an experiment to find the relative formula mass (Mr) of the compound. The Mr of the compound was 44. Relative atomic masses: N = 14; O = 16. What is the formula of the compound?

4/5

Q5.Calculate the percentage of O in Be(OH)₂. Be = 9; O = 16; H = 1.

5/5

Quiz:

# Relative formula mass

This quiz will test your knowledge from this lesson.

Q1.The formula of sodium chloride is NaCl. Calculate the relative formula mass of sodium chloride. Relative atomic masses: Na = 23; Cl = 35.5

1/5

Q2.The formula of magnesium sulfate is MgSO₄. Calculate the relative formula mass of magnesium sulfate. Relative atomic masses: Mg = 24; S= 32; O = 16.

2/5

Q3.Calculate the relative formula mass of iron oxide, Fe₂O₃. Relative atomic masses: O = 16; Fe = 56.

3/5

Q4.A chemist was asked to identify a nitrogen compound. The chemist carried out an experiment to find the relative formula mass (Mr) of the compound. The Mr of the compound was 44. Relative atomic masses: N = 14; O = 16. What is the formula of the compound?

4/5

Q5.Calculate the percentage of O in Be(OH)₂. Be = 9; O = 16; H = 1.

5/5

# Lesson summary: Relative formula mass (FT only)

## Time to move!

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