Question

what is the ratio of number of molecules in 71 grams of chlorine to the number of molecules in 2 grams of H2

options
1)35:5:1
2)1:1
3)2:1
4)1:2

Answer 1

Molar mass = Atomic mass in grams

Therefore, for chlorine

Atomic mass = 35.5 u

Therefore, molar mass = 35.5 g

No. Of moles in 71 g = 71/35.5= 2

No. Of particles in 2 moles = 2*avogadros constant

Similarly, for hydrogen

Atomic mass = 1 and molar mass = 1

There fore, there are two moles in 2 g

No. Of particles= 2* Avogadros constant

Ratio= 2*avogadros constant/2*avogadros constant = 1