How many moles of nitrogen atoms are present in $$8 \mathrm{~g}$$ of ammonium nitrate?

(Molar mass of ammonium nitrate $$=80$$ )

Calculate the $$\mathrm{pH}$$ of a buffer solution containing $$0.01 ~\mathrm{M}$$ salt and $$0.004 \mathrm{~M}$$ weak acid.

$$\left(\mathrm{pK}_{\mathrm{a}}=4.762\right)$$

What volume of ammonia is formed when $$10 ~\mathrm{dm}^3$$ dinitrogen reacts with $$30 ~\mathrm{dm}^3$$ dihydrogen at same temperature and pressure?

Identify number of moles of donor atoms in $$2 \mathrm{n}$$ mole of $$\mathrm{SCN}^{-}$$.