Question

Find the weight of 100 molecules of each of the following substances:
(a) Chlorine gas(b) Calcium oxide(c) Carbon monoxide

Answer 1

a) 1 mole of chlorine gas weighs 71 g and contains $N_a$ molecules.( Avogadro's law)

Where, $N_a$= Avogadro's Number= $6.022\times {10}^{23}$

Thus weight of 100 molecules of chlorine gas is $71\times 100÷N_a=11.78\times {10}^{-21}$

b) Similarly for $CaO$, Ans: $56\times 100÷N_a=9.29\times {10}^{-21}$

c) Similarly for $CO$, Ans: $28\times 100÷N_a=4.64\times {10}^{-21}$