Answer:
80%
Explanation:
First off, we write out the chemical equation for the reaction, assuming the acid used is HCl;
CaCO3 + 2 HCl → CaCl2 + H2O + CO2
1 mol of CaCO3 generates 1 mol of CO2
Molar mass of CaCO3 = 40 + 12 + (3 * 16) = 52 + 48 = 100 g/mol
Molar mass of CO2 =12 + (2*16) = 12 + 32 = 44 g/mol
So mass of CaCO3 = 1 mol * 100 g/mol = 100 g
Mass of CO2 formed = 1 mol * 44 g/mol = 44 g
This means 100g of CaCO3 generated 44g of CO2
How much would then generate 0.44g?
100 = 44
x = 0.44
Upon cross Multiplication we have;
x = (0.44 * 100) / 44
x = 1g
Percent by mass of CaCO3 = (mass of CaCO3 / Mass of Limestone) * 100
Percent by mass of CaCO3 = (1 / 1.25) * 100 = 0.8 * 100 = 80%