Answer:
47%
Explanation:
MgCO₃ (s) → MgO (s) + CO₂ (g)
CaCO₃ (s) → CaO (s) + CO₂ (g)
_______________________
MgCO₃ (s) + CaCO₃ (s) → MgO (s) + CaO (s) + 2CO₂ (g)
MgO: 40.3044 g/mol
MgCO₃: 84.3139 g/mol
CaO:56.0774 g/mol
CaCO₃: 100.0869 g/mol
CO₂: 44.01 g/mol
15.42 g is the total mass of dolomite.
7.85 g is the sum of MgO and CaO produced.
This means that 7.57 g of CO₂ were produced.
44.01 g CO₂_____ 1 mol
7.57 g CO₂ _____ x
x = 0.172 mol CO₂
Considering the global reaction, we had 0.172/2 = 0.086 mol of MgCO₃ in the original sample.
1 mol MgCO₃ _______ 84.3139 g
0.086 mol MgCO₃ ___ y
y = 7.25 g
15.42 g dolomite ______ 100%
7.25 g MgCO₃ ________ z
z = 47%
