# Apatite homework help

chawki

## Homework Statement

Apatite (Ca5(PO4)3F) is used to manufacture fertilizer.

## Homework Equations

How many kilograms of pure phosphorus (P) is included in 1150 kg of apatite?

## The Attempt at a Solution

How we solve this, tell me only first step...
we can't even use the composition percentage law :grumpy:

## Answers and Replies

Homework Helper
Gold Member

Start with the forumla weight of apatite. Convert to moles.

Can you take it from there?

chawki

can you please tell me how to find the formula weight?
i have learnt chemistry ages ago..and it was in french..

maybe you meant the molar mass ? if it's that, then it is 504.31g/mol
504.31 = 1150000/n
n= 1150000/504.31
n= 2280.34mol

Last edited:
Homework Helper
Gold Member

Right, that's how many moles of apatite. How many moles of phosphorous per mole of apatite?

chawki

That's where i'm stuck

Homework Helper
Gold Member

Just look at the empirical formula. You do this part by inspection... nothing to calculate.

chawki

1mole

Homework Helper
Gold Member

So if you were given 1 mole of Ca5(PO4)3F, you would get only one mole of P out of it?

chawki

i'm not sure, i'm confused

chawki

mp/30.97 = 1150000/504.31
mp= 7062.22g

Homework Helper
Gold Member

AxBy gives you x moles of A and y moles of B per mole of AxBy.

How about the moles of P in one mole of Ca5(PO4)3F?

chawki

Three

chawki

So if you were given 1 mole of Ca5(PO4)3F, you would get only one mole of P out of it?

Not necessarly i think

chawki

mp/30.97 = 1150000/504.31
mp= 7062.22g

70622.23

chawki

Please tell me if i'm right

Mentor

No. You have still ignored fact that there are three moles of P per apatite molecule.

chawki

mp/3*30.97 = 1150000/504.31
mp= 211866.709g
mp=211.866Kg

chawki

Mentor

We are not your private tutorial service, aren't we?

Watch significant figures.

chawki

No, You are not. and i want to say that i appreciate having time for posting and replying.
God bless you all.