# Worksheet: Formula Masses

In this worksheet, we will practice calculating formula masses by summing the relative atomic masses of the constituent elements.

Q1:

A sample of neon contains (mass 19.9924 u), (mass 20.9940 u), and (mass 21.9914 u). Calculate to 4 significant figures the average atomic mass of neon in this sample.

Q2:

A sample of magnesium contains (mass 23.98 u), (mass 24.99 u), and (mass 25.98 u). Calculate the average atomic mass of magnesium in this sample.

Q3:

What is the molar mass of methane ()? Give your answer to 1 decimal place.

Q4:

What is the molar mass of diborane ()?

Q5:

What is the molar mass of hydrazine ()? Approximate your answer to 3 significant figures.

Q6:

What is the molar mass of to 2 decimal places?

Q7:

What is the molar mass of aspirin ?

• A169.156 g/mol
• B180.159 g/mol
• C179.15 g/mol
• D196.158 g/mol
• E165.160 g/mol

Q8:

What is the average mass of one molecule of aspirin ?

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