(a) The mass of 5.6 litres fo a certain gas at STP is 12 g. What is the relative molecular mass or molar mass of the gas?
(b) Calculate the volume occupied at S.T.P. by 2 moles of $S O_{2}$

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Solution

a)Mass of gas = 12 g
The volume of 12 g of gas at STP =5.6 L

22.4 L of gas at STP =1 mole
5.6 L of gas at STP = $fraction numerator 5.6 over denominator 22.4 end fraction$ moles =0.25 moles

mass of 0.25 moles of gas =12 g
Mass of 1 mole of gas or molar mass $= \frac{12}{0.25}$ = 48 g/mol
Relative molecular mass of gas =48 u
b)
Recall that the volume occupied by any gas for a given temperature is the same. That volume at STP happens to be 22.4. This value is constant at STP.

The formula would be:
no. of moles = $fraction numerator v o l u m e over denominator c o n s tan t end fraction$
$n equals fraction numerator V over denominator 22.4 end fraction 2 equals fraction numerator V over denominator 22.4 end fraction V equals 44.8 space d m cubed$

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(a) The mass of 5.6 litres fo a certain gas at STP is 12 g. What is the relative molecular mass or molar mass of the gas? (b) Calculate the volume occupied at S.T.P. by 2 moles of SO2

(a) The mass of 5.6 litres fo a certain gas at STP is 12 g. What is the relative molecular mass or molar mass of the gas?
(b) Calculate the volume occupied at S.T.P. by 2 moles of $S O_{2}$