What volume of water will be released as a result of the substitution reaction between 27.3 g of potassium and wada.

Given:
m (K) = 27.3 g
To find:
V (H2) =?
Decision:
1) We draw up the equation of a chemical reaction, let the volume of hydrogen be x l.
2K + 2H2O = 2KOH + H2
2) Find the molecular weight of potassium.
M (K) = 39 g / mol, since potassium 2 is 78 g / mol
3) Find the molar volume of hydrogen.
Vm (H2) = 22.4 L / mol
4) 27.3 g: 78 g / mol = x L: 22.4 L / mol
x = (27.3 x 22.4): 78 = 7.84 liters.
Answer: V (H2) = 7.84 liters.