Balanced chemical equation help (1 Viewer)

[mgg20]

Hi! I need help balancing an equation for my textbook questions and I have tried everything and I can’t seem to work it out.

‘Why is the following equation not balanced? Find the errors and correct them’
3Co3+ + 2HPO42- Co3(PO4)2 + 2H+

thank you!

 

[jazz519]

3Co3+ + 2HPO42- -----> Co3(PO4)2 + 2H+

Balancing an equation is not only making sure you have the correct amount of atoms on each side.
i.e. here on the left: 3Co and 2H and 2PO4
on the right: 3Co 2PO4 and 2H, so it's balanced in that aspect

However, the charges need to also be balanced as well. In a chemical reaction sometimes there is electron transfer, here that charge is not balanced.
i.e. here on the left (add up all the charges): 3x(+3) + 2x(-2) = +5
on the right: 0 (as compound is neutral) + 2x(+1) = +2

So you've got uneven charges on each side. We can balance this by adding 3 electrons to the left, making both sides +2

i.e. 3Co3+ + 2HPO42- + 3e- -----> Co3(PO4)2 + 2H+