Apatite Homework Help - Find P in 1150 kg of Apatite

[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

 

[chemisttree]

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 learned 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

 

[chemisttree]

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

 

[chawki]

That's where I'm stuck

 

[chemisttree]

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

 

[chawki]

1mole

 

[chemisttree]

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]

m_p/30.97 = 1150000/504.31
m_p= 7062.22g

 

[chemisttree]

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

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]

m_p/30.97 = 1150000/504.31
m_p= 7062.22g

70622.23

 

[chawki]

Please tell me if I'm right

 

[Borek]

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

 

[chawki]

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

 

[chawki]

Please reply to my posts!

 

[Borek]

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.