Question

If the molecular weights of $N{H}_3$ and $H_2$ are $17$ amu and $2$ amu respectively, then the number of molecules of $N{H}_3$ in $17gm$ of ammonia is:

• A. less than the number of molecules of $H_2$ in $2$ grams of hydrogen
• B. equal to the number of molecules of $H_2$ in $2$ grams of hydrogen
• C. equal to the number of atoms of $H$ in $2$ grams of hydrogen
• D. more than the number of molecules of $H_2$ in $2$ grams of hydrogen

Answer 1

The correct option is B equal to the number of molecules of $H_2$ in $2$ grams of hydrogen

Mole = Molecular Weight = $6.023\times {10}^{23}$ molecules of compound.

1 mole = 17 gm of ammonia = $6.023\times {10}^{23}$ molecules.

1 mole = 2 gm of hydrogen = $6.023\times {10}^{23}$ molecules.
So, the number of molecules is equal for both ammonia and hydrogen.