# Worksheet: Relative Formula Mass

In this worksheet, we will practice defining relative formula mass and calculating its value for given molecular and structural formulas.

**Q2: **

To the nearest g/mol, what is the relative formula mass of (sodium oxide)?

**Q3: **

What is the M_{r} of phosphorus trifluoride ?

**Q4: **

What is the of silane ?

**Q5: **

What is the of xenon difluoride ?

**Q6: **

The relative atomic mass (A_{r}) of sodium is 23 g/mol, that of oxygen is 16 g/mol, and that of hydrogen is 1 g/mol. What is the relative formula mass (M_{r}) of (sodium hydroxide)?

**Q7: **

Using the Periodic Table to find the relative atomic masses of its elements, calculate the relative formula mass (M_{r}) of (carbon dioxide) to the nearest g/mol.

**Q8: **

Using the Periodic Table to find the relative atomic masses of its elements, calculate the relative formula mass of (formaldehyde).

**Q9: **

What is the relative formula mass of (methanol)? Use the periodic table to find the relative atomic masses of the elements.

**Q10: **

What is the relative formula mass of (magnesium fluoride)?

**Q11: **

What is the relative formula mass of (ammonia)?

**Q12: **

A substance has the formula unit . What is the relative formula mass of this substance in terms of A_{r} and A_{r}, the relative atomic masses of and ?

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**Q13: **

A substance has the formula unit . What is the relative formula mass of this substance in terms of and , the relative atomic masses of and ?

- A
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- E

**Q14: **

The relative atomic mass of carbon is 12 g/mol, and the of oxygen is 16 g/mol. What is the relative formula mass of (carbon monoxide)?

**Q15: **

The relative atomic mass (A_{r}) of carbon is 12 g/mol, and the A_{r} of hydrogen is 1 g/mol. What is the relative formula mass (M_{r}) of (methane)?