## Test 1. Q 3

Posts: 27
Joined: Fri Apr 06, 2018 11:04 am

### Test 1. Q 3

How did you guys go about balancing equation?
__H3PO4 + __Ca(OH)2 ---> __Ca(H2PO4)2+ __H2O

For some reason during the test this had me stumped. Is there an easy trick to apply to these kinds of balancing equation problems?

victoriatanaka1C
Posts: 38
Joined: Fri Apr 06, 2018 11:05 am

### Re: Test 1. Q 3

Someone told me it's a good plan to keep compunds together that appear on both sides, and my TA told me H20, in most cases, requires an even coefficient. So using those guidelines, I compared PO4 on both sides and multiplied the one on the left my 2. With this, Ca and PO4 are in balance. Now there's a total of 8 Hs on the left and 4 on the right. There's also 2 Os on the left and 1 on the right. To balance this remainder, all you have to do is multiply the H20 on the right by 2!

I usually approach balancing equation problems by starting with either or both of these, then working from left to right.

My solution for this problem: 2 H3PO4 = Ca(OH)2 -> Ca(H2PO4)2 + 2H2O

*Disclaimer: I didn't have this question on my test, so I cannot be 100% sure this is correct.