- The mass of 2 moles of H₂O (Molar mass = 18 g/mol) is:
a) 36 g
b) 32 g
c) 40 g
d) 42 g
Answer: a) 36 g
Explanation: 2 moles × 18 g/mol = 36 g.
- How many moles are in 500 g of K₂Cr₂O₇ (Molar mass = 294 g/mol)?
a) 1.7 moles
b) 1.5 moles
c) 2.0 moles
d) 3.0 moles
Answer: a) 1.7 moles
Explanation: 500 g ÷ 294 g/mol ≈ 1.70 moles.
- The molar mass of lead(II) acetate (Pb(C₂H₃O₂)₂) is:
a) 250 g/mol
b) 300 g/mol
c) 340 g/mol
d) 400 g/mol
Answer: c) 340 g/mol
Explanation: Molar mass = 207.2 + 2 × (2 × 12.01 + 3 × 1.01 + 2 × 16) = 340.34 g/mol.
- How many grams are in 1.5 moles of KCl (Molar mass = 74.5 g/mol)?
a) 100 g
b) 110 g
c) 120 g
d) 140 g
Answer: c) 111.75 g
Explanation: 1.5 moles × 74.5 g/mol = 111.75 g.
- The number of moles in 200 g of C₂H₅OH (Molar mass = 46 g/mol) is:
a) 2.5 moles
b) 4.5 moles
c) 3.5 moles
d) 1.5 moles
Answer: a) 4.35 moles
Explanation: 200 g ÷ 46 g/mol ≈ 4.35 moles.
- What is the volume occupied by 12 moles of an ideal gas at STP?
a) 268.8 L
b) 260.8 L
c) 268.2 L
d) 264.4 L
Answer: a) 268.8 L
Explanation: 12 moles × 22.4 L/mole = 268.8 L.
- How many moles are in 80 g of MgCl₂ (Molar mass = 95.3 g/mol)?
a) 0.75 moles
b) 1.0 mole
c) 1.5 moles
d) 2.0 moles
Answer: b) 0.84 moles
Explanation: 80 g ÷ 95.3 g/mol ≈ 0.84 moles.
- The molar mass of sodium acetate (NaC₂H₃O₂) is:
a) 82 g/mol
b) 75 g/mol
c) 100 g/mol
d) 90 g/mol
Answer: a) 82 g/mol
Explanation: Molar mass = 22.99 + (2 × 12.01) + (3 × 1.01) + (2 × 16) = 82.03 g/mol.
- The mass of 4 moles of Na₂S (Molar mass = 78 g/mol) is:
a) 312 g
b) 316 g
c) 320 g
d) 300 g
Answer: a) 312 g
Explanation: 4 moles × 78 g/mol = 312 g.
- How many grams are in 0.2 moles of H₂SO₄ (Molar mass = 98 g/mol)?
a) 16 g
b) 20 g
c) 18 g
d) 22 g
Answer: b) 19.6 g
Explanation: 0.2 moles × 98 g/mol = 19.6 g.
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