the following three wikipedia articles will answer all your questions:

https://en.wikipedia.org/wiki/Mass_fraction_(chemistry)

https://en.wikipedia.org/wiki/Ideal_gas_law

https://en.wikipedia.org/wiki/Stoichiometry

multiply the density into coresponding volume , convert it to mass .. then calculate..

Using the assumption of the ideal gas law 

Then volume fraction = mole fraction 

Dear Sagar

Assuming the following gaseous fuel composition, calculations are as follows 

Volume = 1000 Nm3

CO = 45 (vol.%) and H2 = 55 (vol.%)

Conversion:

      Mass of CO = 1000 * 45% * 28 / 22.424 = 562.1 Kg

      Mass of H2 = 1000 * 55% * 2 / 22.414 = 49.1 Kg

               Total = 562.1 + 49.1

                        = 611.2 Kg

      CO = 562.1 / 611.2 *100  = 92 (mass %)

      H2 = 49.1 / 611.2 * 100 = 8 (mass %)

Thank you

And for Calculating Mole % 

   CO moles = 1000 * 45% /22.414 = 20.1 

   H2 moles = 1000* 55%/22.414 =  24.5 

   Total moles = 44.6 moles 

CO = 20.1 /44.6 * 100 =  45 (mole%)

H2 = 24.5 / 44.6 * 100 = 55 (mole %)

Thank you 

For ideal gas, it is same as volume fraction

How to convert mole fraction to volume fraction?

In the case food samples how do we calculate the volume fraction if we know the mass fraction.

If we know the mass fraction of each constituent of potato lets say protein=2.61g/100g, fat=0.95 g/100g, ash 4.83 g/100g, dry matter 91g/100g and moistre content=81%. based on these data how do we calculate its volume fraction. The density of potato is 1072 kg/m3.

To convert one concentration into another, best use the definition of each of them. The stoichometric coefficients specify the relationship between the number of moles of reacting components in a given chemical reaction and are not related to molar or mass fractions. It is only after you have set the initial number of moles and you take the conversion, you can use the stoichiometric coefficients to find the composition of reaction mixture. Regards,

Agree with Venkatesan J.

Thanks

Dear Venkatesan J sir, what is 22.414 in your calculation?

Ok. Thank you Ma Monazzah sir.