A mixture of CaCO3 and CaO has a mass of 2.750 g. After heating, the mass of the sample is reduced to 2.097 g. What is the mass percent of CaCO3 in the mixture

There is 53.8 % of CaCO3 in the mixture

Explanation:

Step 1: Data given

Mass of mixture = 2.750 grams

Mass after heating = 2.097 grams

Step 2: The balanced equation

CaCO3 → CO2 + CaO

Step 3: Calculate mass CO2 lost

Mass CO2 lost = Mass before heating - mass after heating

Mass CO2 = 2.750 - 2.097 = 0.653 grams

Step 4: Calculate moles CO2

Moles CO2 = Mass CO2 / molar mass CO2

Moles CO2 = 0.653 grams / 44.01 g/mol

Moles CO2 = 0.0148 moles

Step 5: Calculate moles CaCO3

For 1 mol CaO we need 1 mol CO2 for 1 mol CaCO3

For 0.0148 mol CO2 we have 0.0148 mol CaCO3

Step 6: Calculate mass of CaCO3

Mass CaCO3 = moles CaCO3 * molar mass CaCO3

Mass CaCO3 = 0.0148 moles * 100.08 g/mol

Mass CaCO3 = 1.48 grams

Step 7: Calculate mass percent of CaCO3

Mass % CaCO3 = (

There is 53.8 % of CaCO3 in the mixture1.48 grams / 2.750 grams) * 100 %

Mass % CaCO3 = 53.8 %