Question

The molar mass of a gaseous compound XO₂ is 64 gmol^-1. A sample of this gas occupied 11.2dm³ at s.t.p.molar gas volume =22.4dm³.find

1. The number of moles of this gas.
2. The amount in grams that occupied the above volume. 

Answer 1

1. I mole of a gas occupy - 22.4dm³ at s.t.p
                                       ? - 11.2dm^{3
                                            (11.2 x 1)}/_22.4 = 0.5mol 
2. 22.4dm³ → 64g/l
   11.2dm³ → ?
   11.2 x ⁶⁴/_22.4=32g