Homework Help

Analysis of a compound known to contain only Mg, P,and O gives this analysis.21.8% ...

user profile pic

roshan-rox | (Level 1) Valedictorian

Posted June 8, 2013 at 5:27 AM via web

dislike 1 like

Analysis of a compound known to contain only Mg, P,and O gives this analysis.
21.8%  Mg, 27.7% P, 50.5% O
What is its empirical formula?

1 Answer | Add Yours

user profile pic

jeew-m | College Teacher | (Level 1) Educator Emeritus

Posted June 8, 2013 at 5:39 AM (Answer #1)

dislike 1 like

molecular weight

`Mg = 24`

`O = 16`

`P = 31`

 

Let us say we have 100g of compound.

Then we have 21.8g of Mg,27.7 of P and 50.5g of O.

Moles of Mg `= 21.8/24 = 0.908`

Moles of P `= 27.7/31 = 0.894`

Moles of O `= 50.5/16 = 3.156`

 

`M:P:O = 0.908:0.894:3.156 ~= 1:1:3.5 = 2:2:7`

 

So the empirical formulae would be `Mg_2P_2O_7`

Join to answer this question

Join a community of thousands of dedicated teachers and students.

Join eNotes