find the mass of water(H2O) needed to react with 150 grams of potassium(K)

Answer 1

2K + 2H2O ==> 2KOH + 2H2

mols K = grams/molar mass = ?
Using the coefficients in the balanced equation, convert mols K to mols H2O.
That's ? mols K x (2 mols H2O/2 mol K) = ? mols K x 2/2 = ? mols H2O
Now convert mols H2O to grams. g = mols x molar mass.

Answer 2

How do I get the number of moles of H2O

Answer 3

See your other posts.