# Worksheet: Masses and Moles

In this worksheet, we will practice using the formula mass of a compound to convert between the mass of material and number of moles present.

Q1:

Calcium carbonate has the formula .

What is the mass of one mole of calcium carbonate to the nearest gram?

What is the mass of one formula unit of calcium carbonate to 3 significant figures?

• A g
• B g
• C g
• D g
• E g

Calculate to 3 significant figures the number of moles present in 500 g of pure calcium carbonate.

Q2:

Which of the following represents the greatest mass?

• A80 L of oxygen gas at 1.00 bar and 298 K
• B molecules of oxygen gas
• C2.00 mol of calcium oxide
• D3 mol of calcium
• E110 g of calcium

Q3:

When 10.00 g of water partially evaporates, water molecules are removed as vapor. Calculate the mass of water remaining.

Q4:

A packet of an artificial sweetener contains 40.0 mg of saccharin , which has the structural formula shown.

Saccharin has a molar mass of 183.18 g/mol.

How many saccharin molecules are there in the packet of artificial sweetener to three significat figures?

• A
• B
• C
• D
• E

How many carbon atoms are there in this quantity of saccharin to three significat figures?

• A
• B
• C
• D
• E

Q5:

Which of the following is furthest from a mole of atoms?

• A
• B
• C
• D
• E

Q6:

Which of the following is furthest from a mole of molecules/formula units?

• A100.09 g calcium carbonate
• B20.01 g hydrogen fluoride
• C79.90 g bromine gas
• D154.99 g cobalt(II) sulfate
• E16.04 g methane

Q7:

There is approximately 1 g of graphite in a pencil. How many moles of carbon atoms are there in 1.0 g of graphite? Give your answer to three significant figures.

Q8:

Which of the following has the greatest mass?

• A
• B
• C
• D
• E

Q9:

Which of the following contains the greatest number of moles of oxygen atoms?

• A
• B
• C
• D
• E