- #1
HigueraC
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Homework Statement
An unknown compound contains 21.8 g of phosphorus and 28.2 g of oxygen. It's molar mass is 284 g/mol. what are its empirical and molecular formulas?
Elements and the Weight:
P = 31 g/mol
O = 16 g/mol
Given Measurements:
21.8g P, 28.2g O, MM = 284g/mol
2. The attempt at a solution
This is my math:
Elements and the Weight:
P = 31 g/mol
O = 16 g/mol
Given Measurements:
21.8g P, 28.2g O, MM = 284g/mol
Converting the given measurements to moles:
21.8gP / 31 = .70 mol P
28.2gO / 16 = 1.8 mol O
Getting the ratio:
.70 / .70 = 1
1.8 / .70 = 2.57 (rounds up to 3)
Ratio:
1:3
Empirical Formula : PO3
Formula Mass of PO3:
79g/mol
Finding the common factor:
284(the given weight)/ 79(the weight of PO3) = 3.594 (rounds up to 4)
Writing the Molecular Formula:
4(PO3) = P4O12
Getting the Molar Mass of the Molecular Formula:
P4 = 124
O12 = 192
P4O12 = 316
316 =/= 284(is what it should be)