S P Singh Solutions for Chapter: Mole Concept and Stoichiometry, Exercise 3: EXERCISE-5E

Barium chloride crystals contain $14.8 \%$ water of crystallisation. Find the number of molecules of water per molecule.

Urea is a very important nitrogenous fertilizer. Its formula is ${\mathrm{H}}_2\mathrm{N}-\mathrm{C}\left(\mathrm{O}\right)-{\mathrm{NH}}_2$. Calculate the percentage of nitrogen in urea ($\mathrm{C}=12;\mathrm{O}=16;\mathrm{N}=14;\mathrm{H}=1$).

Determine the formula of the organic compound if its molecule contains $12$ atoms of carbon. The percentage compositions of hydrogen and oxygen are $6.48$ and $51.42$ respectively.

A compound with empirical formula ${\mathrm{AB}}_2$, has the vapour density equal to its empirical formula weight. Find its molecular formula.

A compound with empirical formula $\mathrm{AB}$ has vapour density three times its empirical formula weight. Find the molecular formula.

$10.47 \mathrm{g}$ of a compound contained $6.25 \mathrm{g}$ of metal $\mathrm{A}$ and rest non-metal $\mathrm{B}$. Calculate the empirical formula of the compound (At. wt of $\mathrm{A}=207;\mathrm{B}=35.5$).

A hydride of nitrogen contains $87.5$ per cent by mass of nitrogen. Determine the empirical formula of this compound.

A compound has $\mathrm{O}=61.32\%;\mathrm{S}=11.15\%;\mathrm{H}=4.88\%$ and $\mathrm{Zn}=22.65\%$. The relative molecular mass of the compound is $287 \mathrm{a}.\mathrm{m}.\mathrm{u}$. Find the molecular formula of the compound, assuming that all the hydrogen is present as water of crystallisation.