A 26.3754 g sample of impure magnesium car-
bonate was heated to complete decomposition
according to the equation
MgCO3(s) ! MgO(s) + CO2(g) .
After the reaction was complete, the solid
residue (consisting of MgO and the original
impurities) had a mass of 15.4638 g. Assum-
ing that only the magnesium carbonate had
decomposed, how much magnesium carbon-
ate was present in the ori
Arrows can be made --> or ==>
MgCO3 ==> MgO + CO2
26.3754g - 15.4638g = loss in mass = mass CO2.
mass MgCO3 present originally = mass CO2 x (molar mass MgCO3/molar mass CO2) = ?