During a laboratory experiment at 1.0 atm and 25°C?

[匿名]

2017-02-28 2:12 am

During a laboratory experiment at 1.0 atm and 25°C, a student observed that oxygen gas was produced by decomposition of 15g of sodium chlorate. What was the volume of oxygen?

the answer is 5.17 and im wondering what formula my prof did to get that answer. Thanks!

更新1:

5.17 L to be exact

回答 (1)

wanszeto

2017-02-28 2:39 am

✔ 最佳答案

Molar mass of NaClO₃ = (23.0 + 35.5 + 16.0×3) g/mol = 106.5 g/mol
Mass of NaClO₃ decomposed = (15 g) / (106.5 g/mol) = 0.1408 mol

2NaClO₃(s) → 2NaCl(s) + 3O₂(g)
Mole ratio NaClO₃ : O₂ = 2 : 3
No. of moles of O₂ produced = (0.1408 mol) × (3/2) = 0.2112 mol

Consider the O₂ produced :
No. of moles, n = 0.2112 mol
Pressure, P = 1 atm
Absolute temperature, T = (273 + 25) K = 298 K
Gas constant, R = 0.0821 L atm / (mol K)
Volume, V = ?

For a fixed amount of gas: PV = nRT
Then, V = nRT/P

Volume of O₂ produced, V = 0.2112 × 0.0821 × 298 / 1 L = 5.17 L

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