Question

Number of molecules present in 1.12×1÷10000000 cc of gas at STP

Answer 1

remember 1cc = 0.001 litre
so 1.12×1÷10000000 cc =  1.12×$10^{-10}$ litres
we know
22.4litres of gas contains 6.023×$</span>10^{23}$ molecules.
so, 1 litre of gas contains ( 6.023×$</span>10^{23}$ )÷22.4 molecules.
thus,
1.12×$10^{-10}$ litres of gas contains [ ( 6.023×$10^{23}$ )÷22.4]×1.12×$10^{-10}$ molecules
which is approximately 3.0115×$10^{12}$