Question

The maximum number of molecules is present in

a.15L of H_{​​​​​​2} gas at STP

b. 5L of of N_{​​​​​​2} gas at STP

c.0.5g of H_{​​​​​​2} gas

d.10g of O_{​​​​​​2} gas

Answer 1

We can normalise all to one unit i.e. in terms of moles, from which we can say that whichever has greater molar quantity will contain greater number of molecules in it.

(i) Number of moles in 15 L of H2 gas at STP. = (15 L / 22.4 L) = 0.67 moles

(ii) Number of moles in 5 L of N2 gas at STP. = (5 L / 22.4 L) = 0.22 moles

(iii) Number of moles in 0.5 g of ​H2 gas = (0.5 g / 2 g mol-1) = 0.25 moles

(iv) Number of moles in 10 g of O2 gas = (10 g / 32 g mol-1) = 0.312 moles