Q17 of 100 Page 34

The mean speed of the molecules of a hydrogen sample equals the mean speed of the molecules of a helium sample. Calculate the ratio of the temperature of the hydrogen sample to the temperature of the helium sample.

In kinetic theory of ideal gas mean speed also known as average


speed is given as



Where R=gas constant=8.31Jmol-1K-1


T=temperature of gas


M=molar mass of gas


Given



Let temperature of hydrogen gas =T(H)


Temperature of helium gas= T(He)


Molar mass of hydrogen gas =2amu


Molar mass of helium gas =4amu




Squaring both sides



the ratio of the temperature of the hydrogen sample to the temperature of the helium sample is 1:2.


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