Question

(a) Calculate the number of moles in 7 g of nitrogen.
(b) What is the volume at STP of 7.1 g of chlorine?
(c) What is the mass of 56 $c{m}^3$ of carbon monoxide at STP?

Answer 1

(a) 28g of nitrogen =1 mole
So, 7g of nitrogen = $\frac{7}{28}=0.25$ moles

(b)volume of 71 g of $C{l}_2$ at STP =22.4 litres
Volume of 7.1 g chlorine $=7.1\times \frac{22.4}{71}=2.24$ litres

(c) 22400 $c{m}^3$ volume have mass =28 g of CO (molar mass)
so, 56 $c{m}^3$ volume will have mass $=56\times \frac{28}{22400}=0.07g$