Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: cnv22 on July 29, 2018, 11:10:23 AM
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I'm having trouble grasping the logic here with these provided information.
Mass Relationships of Simple Compounds of Nitrogen and Oxygen
Compound Total Mass (g) Mass of Nitrogen (g) Mass of Oxygen (g)
Oxide A 3.28 1.00 2.28
Oxide B 2.14 1.00 1.14
Oxide C 1.57 1.00 0.57
Possible Molecular Formulae for Nitrogen Oxides
Assuming that:
Oxide C is NO Oxide B is NO Oxide A is NO
Oxide A is NO4 NO2 NO
Oxide B is NO2 NO N2O
Oxide C is NO N2O N4O
I understand the logic of the first column (Oxide C is NO), and the corresponding formulas for Oxide A and B in the second column, but I don't understand why the Nitrogen doubles in the second or doubles and quadruples in the second and third columns.
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To be honest I have no idea what the second table is trying to say - are you sure column headings are correct?
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Well, it's clear that for a given mass of nitrogen, the mass of oxygen in oxides A, B and C is in the ratio 4:2:1. So the question is: what oxides fit this pattern. Columns 1, 2 and 3 all fit this pattern. From here there are two ways you could proceed. You could say that NO4 and N4O are unknown, so Column 2 must be the right one. Or you could actually work out the mass ratio of N and O in NO, and see which one fits. Both lead to the same answer.