Question

2K (s) + 2H2O (l) --> 2KOH (aq) + H2 (g)
When 0.400 mole of potassium reacts with excess water at STP, what is the volume of hydrogen gas produced?

the answer is 4.48 liters but I keep getting wrong numbers!
please help!

Thanks!

Answer 1

From the equation 2 moles of K react to form 1 mole of H2 gas. At STP 1 mole of any gas occupies 22.4 litres.

0.400 mol of K will give 0.200 mole of H2 gas.

Volume = 0.200 mole x 22.4 l mole^-1

Answer 2

Thanks!!