- The molar mass of ammonium sulfate ((NH₄)₂SO₄) is:
a) 132 g/mol
b) 150 g/mol
c) 180 g/mol
d) 100 g/mol
Answer: a) 132 g/mol
Explanation: Molar mass = (2 × 14.01) + (8 × 1.01) + 32.07 + (4 × 16) = 132.14 g/mol.
- How many grams are in 0.6 moles of FeCl₃ (Molar mass = 162.2 g/mol)?
a) 90 g
b) 98 g
c) 100 g
d) 110 g
Answer: b) 97.32 g
Explanation: 0.6 moles × 162.2 g/mol = 97.32 g.
- In the reaction: 2Fe + 3Cl₂ → 2FeCl₃, how many moles of Cl₂ are required for 4 moles of Fe?
a) 3 moles
b) 4 moles
c) 5 moles
d) 6 moles
Answer: d) 6 moles
Explanation: The ratio shows that 3 moles of Cl₂ are needed for 2 moles of Fe, so 4 moles of Fe require 6 moles of Cl₂.
- The mass of 0.75 moles of K₂SO₄ (Molar mass = 174.3 g/mol) is:
a) 120 g
b) 130 g
c) 140 g
d) 130.73 g
Answer: d) 130.73 g
Explanation: 0.75 moles × 174.3 g/mol = 130.73 g.
- The number of moles in 25 g of C₂H₄ (Molar mass = 28 g/mol) is:
a) 0.5 moles
b) 1.0 mole
c) 2.0 moles
d) 3.0 moles
Answer: a) 0.89 moles
Explanation: 25 g ÷ 28 g/mol ≈ 0.89 moles.
- The molar mass of copper(II) sulfate (CuSO₄) is:
a) 158 g/mol
b) 160 g/mol
c) 162 g/mol
d) 164 g/mol
Answer: a) 159.61 g/mol
Explanation: Molar mass = 63.55 + 32.07 + (4 × 16) = 159.61 g/mol.
- How many grams are in 2 moles of CH₄ (Molar mass = 16 g/mol)?
a) 30 g
b) 32 g
c) 34 g
d) 36 g
Answer: b) 32 g
Explanation: 2 moles × 16 g/mol = 32 g.
- How many moles are in 100 g of NaOH (Molar mass = 40 g/mol)?
a) 2.0 moles
b) 1.5 moles
c) 2.5 moles
d) 3.0 moles
Answer: a) 2.5 moles
Explanation: 100 g ÷ 40 g/mol = 2.5 moles.
- The molar mass of strontium chloride (SrCl₂) is:
a) 136 g/mol
b) 150 g/mol
c) 180 g/mol
d) 200 g/mol
Answer: c) 158.5 g/mol
Explanation: Molar mass = 87.62 + (2 × 35.45) = 158.52 g/mol.
- The mass of 0.5 moles of H₂SO₄ (Molar mass = 98 g/mol) is:
a) 48 g
b) 49 g
c) 50 g
d) 49 g
Answer: b) 49 g
Explanation: 0.5 moles × 98 g/mol = 49 g.
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