Stoichiometry question.

[exderwall]

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A 2.000g sample of an unknown metal, M, was completely burned in excess O2 to yield 0.02224 mol of the metal oxide, M2O3. What is the metal?

A) Y B) Ca C) Al D) Sc

 

[Morsetlis]

.02224 moles of M2O3 in product => twice that many moles of M needed in reactants = .04448 moles of M

2.000g M / .04448 moles M = 44.96 g/mole = Sc

Dimensional analysis ftw.