Question

Find the mass of water (H2O) needed to react with 150 grams of potassium (K)
2K(s) + 2 H2O (g)-2KOH +H2(g)

How do I get the number of moles in H2O?

Answer 1

Find the mass of water (H2O) needed to react with 150 grams of potassium (K)
2K(s) + 2 H2O (g)-2KOH +H2(g)

How do I get the number of moles in H2O?
Desperate to understand this.
I got K= 150g./39.0983=3.84 mols of K.

Then would it be 3.84(2mols H2O/7.68)
How do I get the proper equation to figure out what 2 moles of H2O would be.
If you can walk me through this problem I will understand it and be able to continue with my work. Please help.

Answer 2

All you needed to do is/was follow my instructions. You found mols K.
See the second step in my earlier post.
http://www.jiskha.com/display.cgi?id=1414442701

Second step. Using the coefficients in the balanced equation, convert mols K to mols H2O. That's ? mols K x (2 mol H2O/2 mols K)
or mols H2O = ?mols K x 2/2 = the same as mols K