Both calcite (CaCO3) and dolomite (CaMgC2O6) are used as dietary calcium supplements. Calculate the mass percentage of calcium in each mineral and determine which one of the two contains the higher percentage of calcium (Ca)?
Calculate the molar mass. I'll do CaMgC2O6: CaMgC2O6 --- 184.399 g/mol We need the atomic weight for one calcium. We look it up on a periodic table: Ca --- 40.08 g/mol Divide the one of one Ca by the weight of the CaMgC2O6: 40.08 / 184.399 0.2174 Multiply by 100 for a percent: 21.74% So, in CaMgC2O6, the percent by mass of the calcium is just a bit under 22%. Follow the same procedure for doing Ca in CaCO3.
The mass percentage is found by the following: mass percentage mass of Ca / mass of molecule * 100% In one mole of calcite, there's one mole of calcium, one mole of carbon, and three moles of oxygen; find the mass of calcium and the molecule. mass of Ca 1mol Ca * 40.078g Ca/1mol Ca 40.078g Ca mass of molecule 1mol CaCO3 * (40.078g Ca + 12.0107g C + 3*15.9994g O)/1mol CaCO3 mass of molecule 100.0869g CaCO3 Find the mass percentage. mass percentage 40.078g Ca / 100.0869g CaCO3 * 100% mass percentage 40.04320246% In one mole of dolomite, there's one mole of calcium, one mole of magnesium, two moles of carbon, and six moles of oxygen; find the mass of calcium and the molecule. mass of Ca 1mol Ca * 40.078g Ca/1mol Ca 40.078g Ca mass of molecule 1mol CaMgC2O6 * (40.078g Ca + 24.3050g Mg + 2*12.0107g C + 6*15.9994g O)/1mol CaMgC2O6 mass of molecule 184.4008g CaMgC2O6 Find the mass percentage. mass percentage 40.078g Ca / 184.4008g CaMgC2O6 * 100% mass percentage 21.73417903% Calcite has the higher percentage of calcium. Hope this helps
