###### Kinetic Theory – Solutions

**1) Estimate the fraction of molecular volume to the actual volume occupied by oxygen gas at STP. Take the diameter of an oxygen molecule to be 3 A.**

Solution:

Radius ‘r’ of an oxygen molecule, r = d/2 = (3/2) A = 1.5 x 10^{-8} cm

Volume occupied by 1 mole of oxygen gas at STP = 22.4 litres = 22400 cm^{3}

Molecular volume of one mole of oxygen gas, V = πr^{3} N

Where, N is Avagadro’s number = 6.023 x 10^{23} molecules/mole

So, V = x 3.14 x (1.5 x 10^{-8})^{3 }x 6.023 x 10^{23}= 8.51 cm^{3}

Ratio of the molecular volume to the actual volume of oxygen = = 3.8 x 10^{-4}

**2) Molar volume is the volume occupied by 1 mole of any (ideal) gas at standard temperature and pressure (STP: 1 atmospheric pressure, 0 ^{0}C). Show that it is 22.4 litres.**

Reviewer

ShikshaHouse

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Reviewed Item

Class 11th Physics - 13 Kinetic Theory - NCERT Solutions

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