What mass of carbon dioxide could be made from 100 tonnes of calcium carbonate?

Total mass of CaCO3 = 40 amu of Ca + 12amu of C + 16×3 amu of oxygen = 100amu of CaCO3

i.e 100 tonnes of CaCO3 .

mass of CO2 = 12amu of C + 2× 16amu of O = 44 amu of CO2

mass % of CO2 in CaCO3 = (44/100)×100 =44%

i.e
44% of 100 tonnes is CO2.
=44 tonnes of CO2.

therefore, 44% of CO2 is present in CaCO3.

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.