Posted by **Tracy** on Tuesday, June 20, 2006 at 3:23pm.

Ok so a quick question. I have the equation Ca3(PO4)2 --> 3Ca+2 + 2PO4-3

Sorr its confusing, int he first part the 3 4 and too are all little numbers at the bottom, for the second part the +2 and -3 are small numbers at the top to show the charges. Ok so anyways the question says if the concentration of Ca2+ is 3.39 x 10^-7 mol/L in a saturated solution of Ca3(PO4)2 what is the concentration of PO4-3. The thing im confused about it, I dont know if that means you need to multiply the Ca concentration by three, then multiply by 2/3 to get the PO4 concentration or if the Ca concentration includes the 3 outside and then divde by 3 ND MULTIPLY by 2.

Ca3(PO4)2 ==> 3Ca^+2 + 2PO4^-3

For every x amount (in molar) of Ca3PO4 that dissolves, we will have 3X for (Ca^+2) and 2X for (PO4^-3). So you divide THE (Ca^+2) GIVEN (they didn't give you 3 times calcium, they gave calcium) by 2 to get X (which is Ca3(PO4)2 and multiply by 2 to obtain (PO4^-3). OK?

So you divide THE (Ca^+2) GIVEN (they didn't give you 3 times calcium, they gave calcium) by 2

Why 2 not 3? I'm so confused now. I divided by 3 then mulipied by 2

So sorry. I goofed. Divide Ca by 3 to get X, then multiply by 2 to obtain PO4.

Thanks very mcuh = )

## Answer this Question

## Related Questions

- chemistry - H3PO4+3Ca(OH)2=Ca3(PO4)2=6H2O If 44.6g of Ca3(PO4)2 are formed in ...
- Chemistry - 3Ca(NO3)2(aq)+2Na3PO4(aq)->Ca3(PO4)2(s)+6NaNO3(aq) (a) the grams ...
- chemistry - the question reads: a) balance the equation: H3PO4 + Ca(OH)2 --> ...
- Chemistry - 3Ca(NO3)2(aq)+2Na3PO4(aq)->Ca3(PO4)2(s)+6NaNO3(aq) A.)the moles ...
- chemistry - Using the balanced equation, determine the number of NaNO3 units in ...
- Chemistry - 3Ca(CH3COO)2(aq) + 2H3PO4(aq) Ca3(PO4)2(aq) + 6CH3COOH (aq) ...
- Chemistry - If you have 225 grams of Ca3(PO4)2, and 185g H3PO4; calculate which ...
- Geo - Just a quick question that will help me in my essay. I just need a quick ...
- Chemistry - Teeth and bones are composed, to a first approximation, of calcium ...
- Chemistry - Teeth and bones are composed, to a first approximation, of calcium ...