Hello i am in AP chem this year and i forgot a lot over the summer. I worked this problem out but i want to make sure i did it correctly. The question is: How many moles of potassium hydroxide are needed to completely react with 3.47 moles of aluminum sulfate according to the balanced equation?

Equation: 6 KOH + 2 Al(OH)3 + 3 K2SO4

I got 20.82 moles of KOH

## Answers (1)

First, your equation is incomplete. I believe it should be:

Al2(SO4)3 + 6 KOH --> 2 Al(OH)3 + 3 K2SO4

You would do the calculation:

3.47 mol Al2(SO4)3 X (6 mol KOH / 1 molAl2(SO4)3) = 20.8 mol KOH.

You should only have 3 significant figures in your answer because your known quantity has only 3.