How many moles of nitrogen atoms are present in $8 \ g$ of ammonium nitrate (in $mol$)?

What is the number of moles of $N$ atoms and number of moles of $O$ atoms respectively present in one mole of uracil?

In which of the following pairs do $1 \text{ g}$ of each contain the same number of molecules?
$(I)\, N_2O$ and $CO$               $(II)\,N_2$ and $CO_2$
$(III)\, N_2$ and $CO$                $(IV) \,N_2O$ and $CO_2$

There are $6.02 \times 10^{22}$ molecules each of $N_2$,$O_2$,and $H_2$ which are mixed together at $760 \ mm$ and $273 \ K$. The mass of the mixture in grams is:

The number of electrons in a mole of hydrogen molecule is

Which one of the following statements is incorrect?