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1.

A 10 g sample of H₂O (Mr = 18). Which option is correct?

moles = 1.8 mol, molecules = 1.67×10²³

moles = 1.11 mol, molecules = 6.02×10²⁴

moles = 1.8 mol, molecules = 3.34×10²³

moles = 0.556 mol, molecules = 3.34×10²³

2.

A 90 g sample of CO₂ (Mr = 44). Which option is correct?

moles = 39.6 mol, molecules = 5.42×10²⁵, volume at STP = 2.02e+03 L

moles = 2.05 mol, molecules = 1.23×10²⁴, volume at STP = 45.8 L

moles = 0.489 mol, molecules = 1.23×10²⁴, volume at STP = 45.8 L

moles = 0.489 mol, molecules = 6.16×10²³, volume at STP = 45.8 L

3.

A 9 g sample of NaCl (Mr = 58.5). Which option is correct?

moles = 0.154 mol, molecules = 9.26×10²²

moles = 5.26 mol, molecules = 4.63×10²²

moles = 0.308 mol, molecules = 2.78×10²³

moles = 6.5 mol, molecules = 9.26×10²²

4.

A 90 g sample of O₂ (Mr = 32). Which option is correct?

moles = 0.356 mol, molecules = 5.42×10²⁵, volume at STP = 31.5 L

moles = 0.356 mol, molecules = 8.47×10²³, volume at STP = 63 L

moles = 0.356 mol, molecules = 5.08×10²⁴, volume at STP = 67.5 L

moles = 2.81 mol, molecules = 1.69×10²⁴, volume at STP = 63 L

Chapter 1 — Chemical Calculation — Picture questions (exam style)