# Balance the equation

I'm having trouble balancing this equation. I'm positive I've written the forumla out correctly. Maybe there is a typo somewhere...

The question is:

magnesium hydroxide(aq) + ammonium phosphate(aq) --> magnesium phosphate(c) + ammonia(g) + water(l)

This is the forumla I wrote out as:

MgOH(2) + (NH(4))3PO(4) --> Mg(3)(PO(4))2 + NH(3) + H(2)O

Any ideas or suggestions? Thanks

Monique
Staff Emeritus
Gold Member
Your reaction is not balanced, look at the numner of oxygen atoms you have before and after the reaction.. neogenesis? :P

O: 14 to 9
check out your other atoms and figure out what is wrong with the equation.

Mg for instance, before the reaction you have got one molecule, after you magically have 3?

ShawnD
Ok based on the equation you gave, I think I got her.

3Mg(OH)2 + 2(NH4)3PO4 ---> Mg3(PO4)2 + 6NH3 + 6H20

I balanced it in this order:
1. balance P
2. balance N
3. balance Mg
4. balance O
5. balance H

Monique
Staff Emeritus
Gold Member
I think a good stragegy might be balancing the atoms first, which are present only in one molecule at each side of the arrow.

So Shawn, your example is good since H was balanced last, O one before the last. That is good thinking.

Another God
Staff Emeritus
Gold Member
3Mg(OH)2 + 2(NH4)3PO4 ---> Mg3(PO4)2 + 6NH3 + 6H20

$$3Mg(OH)_2 + 2(NH_4)_3PO_4 \longrightarrow Mg_3(PO_4)_2 + 6NH_3 + 6H_2O$$