A basic Chemistry question about Apatite

• February 3rd, 2014, 11:48 PM
aic18
A basic Chemistry question about Apatite
Hi there! I'm going over some past papers for a university and found this question...unfortunately they don't give the ANSWERS :sad:

The problem is: Apatite (Ca5(PO4)3F) is used to manufacture fertilizer. How many kilograms of pure phosphorus (P) is included in 1150 kg of apatite?

I found the molar masses to be as follows:
Ca: 40.08
P: 30.974
O: 15.999
F: 18.998

What I did was added them up as shown in the formula (i.e. 40.08 x 5 + (30.974 + 15.999 x 4) x 3 + 18.998 = 504.308) then I divided the amount of phosphorous (3 x 30.974) by the total amount (504.308) and got approx. 0.184 ...I'm not sure if that step was right but I kept going! Since the amount of phosphorous makes up 0.184 of the total amount I went 1150(kg) x 0.184 and got approx. 211.9 kilograms.

SO basically my answer is 211.9 kg but I have no idea if it is right or completely wrong! Can someone please help me?

Thank you all! :)
• February 4th, 2014, 03:54 AM
exchemist
Quote:

Originally Posted by aic18
Hi there! I'm going over some past papers for a university and found this question...unfortunately they don't give the ANSWERS :sad:

The problem is: Apatite (Ca5(PO4)3F) is used to manufacture fertilizer. How many kilograms of pure phosphorus (P) is included in 1150 kg of apatite?

I found the molar masses to be as follows:
Ca: 40.08
P: 30.974
O: 15.999
F: 18.998

What I did was added them up as shown in the formula (i.e. 40.08 x 5 + (30.974 + 15.999 x 4) x 3 + 18.998 = 504.308) then I divided the amount of phosphorous (3 x 30.974) by the total amount (504.308) and got approx. 0.184 ...I'm not sure if that step was right but I kept going! Since the amount of phosphorous makes up 0.184 of the total amount I went 1150(kg) x 0.184 and got approx. 211.9 kilograms.

SO basically my answer is 211.9 kg but I have no idea if it is right or completely wrong! Can someone please help me?

Thank you all! :)

This must be a pretty feeble university. Sounds more like homework. Check in your textbook and see what your teacher has to say.
• February 4th, 2014, 06:04 AM
aic18
I don't have a professor, these are just practice questions -.-
• February 4th, 2014, 08:35 AM
Warron