Question

Dolomite, [CaMg(CO3)2] is found in a soil sample. A geochemist titrates 24.65 g of soil with 57.85 mL of 0.3315M HCl. What is the mass % of dolomite in the soil? ( Write answer to two decimal places, ex. 15.77)

Answer 1

In order to find out the %mass dolomite in the soil, calculate for the mass of dolomite using the information given from the titration procedure. You would need to multiply 57.85 ml with 0.3315 M HCl and you would get the amount of HCl in millimoles. Then multiply the amount of HCl with 1/2 (given that for every 1 mol of dolomite, 2 mol of HCl would be needed). Convert the amount of dolomite to mass by multiplying the millimoles with the molecular weight which is 184.399. Then convert the mass to grams which is 1.768 grams. Divide the mass of dolomite (1.768 grams) with the weight of soil sample. The % mass is 7.17.