Question

How many grams of hydrogen gas will be produced if 2.5 mol of tin react?
$S{{n}_{\left( s \right)}}+2H{{F}_{\left( g \right)}}\to Sn{{F}_{2\left( s \right)}}+{{H}_{2\left( g \right)}}$ .

Answer 1

The given problem is fairly based on the basic concepts of stoichiometry and the mole concepts. The balanced chemical equation can help us solve the given query very well; which actually is given.

Complete step-by-step answer: Let us solve this problem stepwise;
A balanced equation will be responsible to provide us with correct stoichiometric coefficients which helps in solving the further problem;
The given equation is;
$S{{n}_{\left( s \right)}}+2H{{F}_{\left( g \right)}}\to Sn{{F}_{2\left( s \right)}}+{{H}_{2\left( g \right)}}$
which describes that,
1 mole of tin is equivalent to 1 mole of hydrogen produced i.e.
$1moleSn\equiv 1mole{{H}_{2}}$
Now, we have given the amount of tin reacted. Thus, equating that we get;
Moles of ${{H}_{2}}=2.5moleSn\times \dfrac{1mole{{H}_{2}}}{1moleSn}=2.5mole{{H}_{2}}$
Now, we need to find the mass of hydrogen produced;
Mass of ${{H}_{2}}=2.5mole{{H}_{2}}\times \dfrac{2g{{H}_{2}}}{1mole{{H}_{2}}}=5g{{H}_{2}}$
As, the molar mass of hydrogen is 2 g/mole.

Note: Do note to use and involve proper units while you solve the problems completely based on the stoichiometry of the reaction. The concept of mole ratio also can be used as it is similar to that of stoichiometry i.e. ratio of stoichiometric coefficients gives the mole ratio of reactants or products.