Question

Which of the following contains more number of
molecules
[hint: H=1 C=12 O=16]
100g
H2
220g
CO2​

Answer 1

Answer:

100g of $H_{2}$:

Molecular mass of $H_{2}$ = 2 x 1 = 2u

Number of moles = 100g/2u = 50 moles

Number of molecules = 50 moles x 6.022 x $10^{23}$ = 301.1 x $10^{23}$

220g of $CO_{2}$:

Molecular mass of $CO_{2}$ = (1 x 12) + (2 x 16) = 12 + 32 = 44u

Number of moles = 220g/44u = 5 moles

Number of molecules = 5 moles x 6.022 x $10^{23}$ = 30.11 x $10^{23}$

Clearly,

30.11 x $10^{23}$  < 301.1 x $10^{23}$

So, 100g of $H_{2}$ has the greater number of molecules.