Mole Concept

1. How many moles are there in 10.0 g of water? (Molar mass = 18.0 g/mol)

• 0.56 mol
• 0.75 mol
• 0.44 mol
• 0.30 mol

2. What is the mass of 0.5 mol of CO₂? (Molar mass = 44.0 g/mol)

• 20.0 g
• 22.0 g
• 18.5 g
• 12.0 g

3. How many molecules are present in 0.2 mol of oxygen gas (O₂)?

• 1.204x10²²

• 1.204x10²³

• 1.00 x10²³

• 6.022x10²³

4. What is the number of moles in 1.204x10²⁴ molecules of NH₃?

• 1.00 mol
• 2.00 mol
• 3.00 mol
• 0.50 mol

5. What is the volume at STP of 3.00 mol of nitrogen gas (N₂)?

• 44.8 dm³

• 67.2 dm³

• 24.0 dm³

• 22.4 dm³

6. A sample contains 6.022x10²² molecules of methane (CH₄). How many moles of methane are there?

• 0.10 mol
• 0.12 mol
• 0.01 mol
• 0.001 mol

7. Determine the number of molecules in 18 g of water. (Molar mass = 18.0 g/mol)

• 6.022x10²²

• 3.34x10²³

• 6.022x10²³

• 1.00x10²⁴

8. What is the molar volume of a gas at STP?

• 22.4 cm³

• 22.4 dm³

• 2.24 dm³

• 24.0 dm³

9. How many atoms of oxygen are there in 2.00 mol of CO2?

• 2.00X10²³

• 4.00X10²³

• 6.02X10²³

• 2.41X10²⁴

10. What volume would 5.00 g of helium gas occupy at STP? (Molar mass = 4.00 g/mol)

• 11.2 dm³

• 28.0 dm³

• 2.80 dm³

• 10.0 dm³