calculate the mass of CO2 obtained when HCL reacts with 15g CACO3.

Follow the steps.

http://www.jiskha.com/science/chemistry/stoichiometry.html

To calculate the mass of CO2 obtained when HCl reacts with 15g CaCO3, you need to follow a few steps:

1. Write a balanced chemical equation for the reaction between HCl and CaCO3:
CaCO3 + 2HCl -> CaCl2 + CO2 + H2O

2. Determine the molar mass of CaCO3 and CO2:
Molar mass of CaCO3 = 40.08 g/mol (atomic mass of Ca) + 12.01 g/mol (atomic mass of C) + 3(16.00 g/mol) (atomic mass of O) = 100.09 g/mol
Molar mass of CO2 = 12.01 g/mol (atomic mass of C) + 2(16.00 g/mol) (atomic mass of O) = 44.01 g/mol

3. Convert the given mass of CaCO3 to moles:
Moles of CaCO3 = Mass of CaCO3 / Molar mass of CaCO3
Moles of CaCO3 = 15 g / 100.09 g/mol = 0.1499 mol

4. Use the stoichiometry of the balanced chemical equation to determine the moles of CO2 produced:
According to the balanced equation, 1 mole of CaCO3 produces 1 mole of CO2.
Moles of CO2 = Moles of CaCO3 = 0.1499 mol

5. Convert moles of CO2 to mass:
Mass of CO2 = Moles of CO2 x Molar mass of CO2
Mass of CO2 = 0.1499 mol x 44.01 g/mol = 6.596 g

Therefore, the mass of CO2 obtained when HCl reacts with 15g CaCO3 is approximately 6.596 grams.