Question

Calculate the mass of 0.2 moles of oxygen molecules

Answer 1

________________________________________________________________________________________________________________________________


1 mole of the oxygen = 16 g 

1 / 20 mole = 16/ 20  g

0.2 mole = 0.8 g mass of oxygen

Hope it help you :)
_____________________________________________________________

Answer 2

lmole=16gms
0.2 moles=x
by cross multiplication
1×x=0.2×wt

x=16/5
=3.2