How many molecules are present in one gram of hydrogen? (Value $\times 10^{23}$)

The amount of oxygen in $3.6 \, \text{moles}$ of water is ............ $g$.

Maximum number of molecules will be in $:-$

The molar mass of $CO_2$ is $44 \ g/mol$. Given that the Avogadro constant is $6.022 \times 10^{23} \ mol^{-1}$,the mass of one molecule of $CO_2$ is ..... $\times 10^{-23} \ g$.

Which of the following relations is incorrect?

The mass of $0.1 \ mol$ of methane $(CH_4)$ is .......... $g$.