Use chemical formulas to generate the stoichiometric factor needed to express the results of a gravimetric analysis in terms of the substance on the left if the weighting form is the substance on the right:

Question

Sought Weighted
I Mg Mg2P2O7
II UO2 U3O6

Answer 1

You're looking for what we called in much earlier days the chemical factor. It is taught less and less theses days but is very useful.
2Mg/Mg2P2O7

3UO2/U3O6 (NOTE: I assume U3O6 is a made up part of the problem. I would have written it as UO2 but then there is no conversion fctor needed.)