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Question
Samples of the gases O2, N2, CO2 and CO under the same conditions of temperature and pressure contain the same number of molecules x. The molecules of oxygen occupy V litres and have a mass of 8 g under the same conditions of temperature and pressure.
What is the volume occupied by:
- x molecules of N2,
- 3x molecules of CO,
- What is the mass of CO2 in grams?
- In answering the above questions, which law have you used?
Solution
Equal vols. of all gases under similar conditions of temperature and pressure occupy equal number of molecules.
(a) x molecules of nitrogen occupies vol. = V litres
(b) 3x molecules of CO gas occupy vol = 3 V litres
(c) x molecules of O2 = `8/32= 1/4` molecule of O2
∴ x molecules of CO2 = `1/4` molecule of CO2
∴ Mass of CO2 present in the sample = `1/4 xx "gram molecular mass of CO"_2`
= `1/4 xx 44`
= 11 g
(d) Avogadro's Law.
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