Question

Calculate the number of molecules in 22 gram of Methane

Answer 1

given ,
mass (m) =22
molecular mass of methane (M) = 1×atomic mass of C + 4× atomic mass of H
=1×12+4×1
=16
number of moles= m/M
=22/16
=1.375
number of molecules=n× avogadro's number
= 1.375×6.022×10^23
=8.20825×10^23

Answer 2

Methane's chemical formula is CH4

So its molecular mass = molecular mass of C + molecular mass of H × 4

= 12 + 1 × 4

= 12 + 4

= 16 u

So molar mass would be 16 g

Now given mass = 22g

Molar mass = 16 g

Mole = given mass/ molar mass

= 22/16

= 11/8 mol

Number of molecules = mol × Avogadro number

= 11/8 × 6.022 × 10²³

= 8.28025 × 10²³ molecules.


Or,

8.28 × 10²³ molecules (approx)