Chemistry questions?

[匿名]

2018-03-16 12:16 am

1.) What would be the mass of 4.56×10^23 water molecules?

2.) How much space would 39.9g of nitrogen gas occupy at SATP?

3.) What would be the mass of a 33.5dm^3 sample of O2 at STP?

回答 (1)

wanszeto

2018-03-16 12:47 am

✔ 最佳答案

1.)
Molar mass of H₂O = (1.0×2 + 16.0) g/mol = 18.0 g/mol
Avogadro constant = 6.022 × 10²³ /mol

Mass of H₂O = [(4.56 × 10²³ g) / (6.022 × 10²³ /mol)] × (18.0 g/mol) = 13.6 g

2)
Molar volume of any gas at SATP = 24.8 dm³/mol
Molar mass of N₂ gas = 14.0 × 2 g/mol = 28.0 g/mol

Space occupied by N₂ gas = [(39.9 g) / (28.0 g/mol)] × (24.8 dm³/mol) = 35.5 dm³

3)
Molar volume of any gas at STP = 22.4 dm³/mol
Molar mass of O₂ gas = 16.0 × 2 g/mol = 32.0 g/mol

Mass of O₂ = [(33.5 dm³) / (22.4 dm³/mol)] × (32.0 g/mol) = 47.9 g

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