Answer:
38.83 % of CaCO3
61.17 % of MgCO3
Explanation:
where Moles of CaCO3 is equals to x and MgCO3 is y we have that...
CaCO3 molar mass = 100.09 g / mol = 100.09 x
MgCO3 molar mass = 84.31 g / mol = 84.31 y
decomposition reactions :
CaCO3 ---> CaO + CO2
MgCO3 ---> MgO + CO2
So we have that , Moles of CaO = Moles of CaCO3 = x
and Moles of MgO = Moles of MgCO3 = y
CaO molar mass = 56.08 g / mol
MgO molar mass = 40.30 g / mol
CaO = 56.08 x
MgO = 40.30 y
"If the weight of the combined oxides is equal to 51.00% of the initial sample weight,"
total mass of MgO and CaO = 51.00 % of Total Mass of MgCO3 and CaCO3
thus
56.08 x + 40.30 y = 0.51 ( 100.09 x + 84.31 y )
56.08 x + 40.30 y = 51.04 x + 42.99y
5.04 x = 2.7 y
y = 1.87 x
CaCO3 % in the sample
= 100.09 x × 100 / ( 100.09 x + 84.31 y )
= 10009 x / ( 100.09 x + 84.31 × 1.87 x )
= 10009 x / ( x ( 100.09 + 157.66 ) )
= 10009 / 257.75
= 38.83 %
MgCO3 % in the sample
= 100 - 38.83
= 61.17 %
