Moles and stoichiometry

How many moles are there in 36 g of water? (H = 1, O = 16)

• 1 3 moles
• 2 2 moles
• 3 1 mole
• 4 0.5 mole

What is the mass of 0.5 mole of carbon dioxide? (C = 12, O = 16)

• 1 11 g
• 2 22 g
• 3 44 g
• 4 88 g

How many molecules are there in 2 moles of a substance? (Avogadro's number is 6.02 x 10^23.)

• 1 3.01 x 10^23
• 2 1.204 x 10^24
• 3 6.02 x 10^23
• 4 1.204 x 10^23

A compound contains 40% carbon, 6.7% hydrogen and 53.3% oxygen by mass. Its empirical formula is:

• 1 C2H2O
• 2 CHO
• 3 CH2O
• 4 C2H4O2

What volume do 2 moles of any ideal gas occupy at STP?

• 1 44.8 dm3
• 2 22.4 dm3
• 3 67.2 dm3
• 4 11.2 dm3

In the reaction 2H2 + O2 -> 2H2O, how many moles of water form from 4 moles of H2 and 1 mole of O2?

• 1 1 mole
• 2 2 moles
• 3 3 moles
• 4 4 moles

What is the molarity of a solution made by dissolving 4 g of NaOH in enough water to make 500 mL? (Na = 23, O = 16, H = 1)

• 1 0.8 M
• 2 0.2 M
• 3 0.1 M
• 4 0.4 M

What is the percentage of oxygen by mass in water? (H = 1, O = 16)

• 1 50%
• 2 88.9%
• 3 94.4%
• 4 11.1%

How many moles of oxygen atoms are in 1 mole of H₂SO₄?

• 1 1
• 2 6
• 3 2
• 4 4

The empirical formula of a compound with the molecular formula C₆H₁₂O₆ is:

• 1 C₂H₄O₂
• 2 CH₂O
• 3 C₃H₆O₃
• 4 C₆H₁₂O₆

What mass of calcium oxide forms when 100 g of calcium carbonate decomposes completely? (CaCO₃ = 100, CaO = 56)

• 1 56 g
• 2 44 g
• 3 28 g
• 4 100 g