- In the reaction 2Na + Cl₂ → 2NaCl, how many moles of sodium are required to produce 2 moles of sodium chloride?
a) 1 mole
b) 2 moles
c) 3 moles
d) 4 moles
Answer: b) 2 moles
Explanation: The mole ratio indicates that 2 moles of sodium produce 2 moles of sodium chloride.
- How many grams are in 0.75 moles of C₁₂H₂₂O₁₁ (Molar mass = 342 g/mol)?
a) 150 g
b) 250 g
c) 250.5 g
d) 275 g
Answer: c) 256.5 g
Explanation: 0.75 moles × 342 g/mol = 256.5 g.
- The number of moles in 15 g of glucose (C₆H₁₂O₆) is:
a) 0.5 moles
b) 0.08 moles
c) 1.0 mole
d) 0.6 moles
Answer: b) 0.08 moles
Explanation: 15 g ÷ 180 g/mol ≈ 0.083 moles.
- What is the molar mass of ammonium phosphate ((NH₄)₃PO₄)?
a) 132 g/mol
b) 115 g/mol
c) 164 g/mol
d) 150 g/mol
Answer: c) 164 g/mol
Explanation: Molar mass is calculated as (3 × 14) + (12 × 1) + 31 + (4 × 16) = 164 g/mol.
- The mass of 3 moles of NH₄NO₃ (Molar mass = 80 g/mol) is:
a) 240 g
b) 150 g
c) 180 g
d) 120 g
Answer: a) 240 g
Explanation: 3 moles × 80 g/mol = 240 g.
- How many grams are in 0.25 moles of Ca(OH)₂ (Molar mass = 74 g/mol)?
a) 18.5 g
b) 20 g
c) 16 g
d) 15 g
Answer: a) 18.5 g
Explanation: 0.25 moles × 74 g/mol = 18.5 g.
- What is the volume occupied by 10 moles of an ideal gas at STP?
a) 112.0 L
b) 224.0 L
c) 300.0 L
d) 280.0 L
Answer: b) 224.0 L
Explanation: 10 moles × 22.4 L/mole = 224.0 L.
- The number of moles in 50 g of NaCl (Molar mass = 58.5 g/mol) is:
a) 0.85 moles
b) 0.75 moles
c) 0.68 moles
d) 0.60 moles
Answer: a) 0.85 moles
Explanation: 50 g ÷ 58.5 g/mol ≈ 0.85 moles.
- The molar mass of silver nitrate (AgNO₃) is:
a) 169 g/mol
b) 170 g/mol
c) 160 g/mol
d) 150 g/mol
Answer: a) 169 g/mol
Explanation: Molar mass = (107.87) + (14.01) + (3 × 16) = 169.87 g/mol.
- In the reaction 4HCl + O₂ → 2Cl₂ + 2H₂O, how many moles of HCl are needed to produce 2 moles of Cl₂?
a) 2 moles
b) 4 moles
c) 6 moles
d) 1 mole
Answer: b) 4 moles
Explanation: The reaction shows a mole ratio of 4:2, so to produce 2 moles of Cl₂, 4 moles of HCl are required.
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