Limestone is a binary mixture of calcium and magnesium carbonates, CaCO3 and MgCO3. At 500 C, MgCO3 thermally decomposes according to the reaction shown, while CaCO3 remains unchanged.
MgCO3(s)=MgO(s)+CO2(g)
When heated at 500C, a 2.000g sample of limestone from a local quarry loses 0.273g. Calculate mass percent of MgCO3 present in the limestone.

I worked it out using both algebraic and theoretical yield methods, and got different answers. Help please!

Question

Limestone is a binary mixture of calcium and magnesium carbonates, CaCO3 and MgCO3. At 500 C, MgCO3 thermally decomposes according to the reaction shown, while CaCO3 remains unchanged. 
MgCO3(s)=MgO(s)+CO2(g)
When heated at 500C, a 2.000g sample of limestone from a local quarry loses 0.273g. Calculate mass percent of MgCO3 present in the limestone.

I worked it out using both algebraic and theoretical yield methods, and got different answers. Help please!

aaronq · Answer

show your work, ill tell you where you went wrong

anonymous · Answer

I think I may have corrected it, would this be right?
.273g CO2->mols CO2->molsMgCO3->.523gMgCO3
(.523gMgCO3/2.00g mixture)(100%)=26.18% MgCO3

aaronq · Answer

yeah that looks correct

preetha · Answer

Looks good to me too!