Answer:
when CO2 gas is passed through lime water it turns milky due to the formation of calcium carbonate which formula is CaCO3.
Ca(OH)2+ CO2------ CaCO3
when excess of carbon dioxide is passed through calcium carbonate calcium hydrogen carbonate is formed and solution become colourless.
CaCO3+CO2------ Ca(HCO3)
A metalloid is a metal and a nonmetal
Chemical changes only happen when the object changes form. Color is a physical property because you're not changing the object that you have, compressibility is also a physical property because you still have the same substance before and sfter, malleability again is another physical. Heat of combustion is physical, when you burn things it changes the substance. :)