K3po4 + al(no3)3 → kno3 + alpo4 moles kno3 from 2.5 moles potassium phosphate

This is a stoichiometry problem. Lets walk through the steps.

First, we will start with our given. This ALWAYS goes over one, never another number. We know our given is 2.5 moles.

So, our 1st step would look like this:

2.5

  1

Then, we need to cancel out the potassium phosphate, since we are trying to find the moles of KNO3 FORMED from it. So, we will use the balanced chemical to find the number of moles we have of the potassium phosphate in the equation, which is one. So, 1 mole of potassium phosphate will go on the bottom of our second step.

Then, we will use our chemical equation to determine how many moles we have present of KNO3. This is not our final answer, since we are trying to figure out how many moles are formed from the 2.5 moles.

By looking at the equation,  we can see there is 1 mole of KNO3 present. So this number goes on top of the second step, since this is what we are trying to find.

So, our equation will look like this:

2.5 mol K3PO4      1 mol KNO3
x
            1                  1 mol K3PO4

Then, what we do is we multiply the two top numbers together, which is 2.5.
Them, we multiply the two bottom numbers together, which is 1.

Then, we divide the top total by the bottom total. 
2.5/1 is 2.5

So, 2.5 moles of KNO3 is formed from 2.5 moles of K3PO4.

Hope I could help!

Noble gases is far right