Potassium metal reacts with water to give potassium hydroxide and hydrogen gas. If 50.0 mL of hydrogen gas is produced at STP, what is the mass of potassium that reacted?

Question

2K(s) + 2 H2O (l) -> 2 KOH (aq) + H2(g)

Answer 1

mols H2 gas = mL/22,400 = ?
Using the coefficients in the balanced equation, convert mols H2 gas to mols K.
Now convert mols K to grams. g = mols K x atomic mass K = ?