Question

Calculate the number of moles and number of molecules of 12 g of carbon, 64 g of

oxygen & 72 g of water. (At masses: C = 12, O = 16, H = 1)​

Answer 1

Answer:

a) 12 g of carbon

Given mass : 12 g

No. of moles =mole. massGiven mass=1212=1 mole

No. of molecules = No. of moles × Avagadro No.

=1×6.22×1023

=6.022×1023 molecules

b) 64 g of oxygen

Given mass: 64 g

No. of moles =mole. massGiven mass=1664=4 mole

No. of molecules = No. of moles ×NA

=4×6.22×1023

=24.088×1023 molecules

c) 72 g of water

Given mass =72 g

Molecular mass =18 g

No. of moles =1872=4 mole

No. of molecules =4×6.22×1023

=24.088×1023 molecules