• The mass of CaCO3 (AR grade) solid to prepare a 1000 ppm Ca solution in a 500 mL volumetric flask.

Question

The mass of CaCO₃ (AR grade) solid to prepare a 1000ppm Ca solution in a 500mL volumetric flask

Answer 1

A brief Google search tells me that the purity of AR CaCO₃ is about 99%.

The MW of CaCO₃ is 100.0869 g/mol

Each 100.0869 g CaCO₃ contain 40.078 g Ca.

1000 ppm Ca solution has concentration of 1000 mg Ca / L

500 mL of such solution should contain 500 mg Ca

The required mass of pure CaCO₃ is then

500 mg Ca x (100.0869 g/mol CaCO₃) / (40.078 g/mol Ca) = 1,249 mg CaCO₃

A brief Google search tells me that the purity of AR CaCO₃ is about 99%, so you need to weigh

1,249 mg / 0.99 = 1,261 mg