If some of the CaCO3 in the sample had already formed some Ca(HCO3)2, will the volume of CO2(g) generated in the reaction be greater,less than or the same as in the experiment? Explain

Answer 1

I don't know what you are doing. If you are generating CO2 from CaCO3 which may have formed some Ca(HCO3)2 in the process, adding acid will generate all of the CO2 and the formation of the intermediate Ca(HCO3)2 will be of no consequence.