Question

if molecules are removed from 200mg of , then the number of moles of left are (a) (b) (c) (d)

Answer 1

If molecules are removed from 200mg of,then the number of moles of left are-(a)

Answer 2

$\Huge{\mathfrak{\underline{\underline{answer}}}}$

⇒Molar mass of N₂O = 44

⇒Mass of N₂O = 200mg = 0.2g

⇒moles of N₂O present 

= 0.2/44

= 4.55×10^(-3) moles

⇒Let moles of N₂O removed = x

⇒moles of N₂O remained = 2.89×10^(-3)

⇒Thus 4.55×10^(-3) - x = 2.89×10^(-3)

⇒ -x = 2.89×10^(-3) - 4.55×10^(-3) 

⇒ x = 4.55×10^(-3) - 2.89×10^(-3)

⇒ x = 1.66×10^(-3) moles

⇒No. of molecules in 1 mole

= 6.022×10²³

⇒No. of molecules in x moles

= y×6.022×10²³

= 1.66×10^(-3)×6.022×10²³

=9.97×10^(20)