Trimix 10/50 is a gas mixture that contians 10% oxygen and 50% helium, and the rest is nitrogen. if a tank of trimix 10/50 has a total pressure of 2.07 x 104 kpa, then what is the partial pressure of helium?

Answer : The partial pressure of helium is,

Solution : Given,

Molar mass of = 32 g/mole

Molar mass of helium = 4 g/mole

Molar mass of = 28 g/mole

Total pressure of gas =

As we are given gases in percent, that means 10 g of oxygen gas, 50 g of helium gas and 40 g of nitrogen gas present in 100 g of mixture.

First we have to calculate the moles of oxygen, helium and nitrogen gas.

Now we have to calculate the total number of moles of gas mixture.

Now we have to calculate the moles fraction of helium gas.

Now we have to calculate the partial pressure of helium.

where,

= partial pressure of helium

= total pressure

= mole fraction of helium

Now put all the given values in this formula, we get

Therefore, the partial pressure of helium is,

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