What mass of tin reacted with hydrochloric acid if 151.2 liters of hydrogen were released as a result?

Given:
m (H2) = 151.2 l
To find:
m (Sn) =?
Decision:
1) Let’s compose the equation of the chemical reaction, let the mass of tin be x g.
Sn + 2HCl (dil.) = SnCl2 + H2
2) Find the molecular weight of tin.
M (Sn) = 119 g / mol.
3) Vm (H2) = 22.4 L / mol.
4) x g: 119 g / mol = 151.2 L: 22.4 L / mol
x = (119 x 151.2): 22.4 = 803.25 g
Answer: m (Sn) = 803.25 g.