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Find out the number of molecules in a ga...

Find out the number of molecules in a gas of volume `20cm^3` at a pressure of 76 cm of mercury. And at `27^@C` Given average molecule kinetic energy at `27^@C=2 times 10^-14 erg`.

Text Solution

Verified by Experts

Pressure of the gas
`p=1/3pc^2=1/3(mN)/Vc^2`
[m=mass of a molecule,N=number of molecules]
or, `N=(3pV)/(mc^2)=(3pV)/(2times1/2mc^2)`
[average molecular kinetic energy `=1/2 mc^2=2 times 10^-14 erg`]
`=(3times(78times13.8times980)times20)/(2times(2times10^-14))`
`=1.52times10^21`
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