Question

If Calcium Carbonate is insoluble when mixed in water what change would occur? A physical or chemical change? Help!

Answer 1

CaCO3 does not dissolve in water. So it is still CaCO3. The solvent still is H2O. No change in substance; therefore, physical change. For a chemical change to occur the final material/substance must be different than the starting material. If I melt ice (solid H2O) so it is liquid (H2O), that's a physical change because H2O still is H2O. If we add that CaCO3 to the H2O it is still CaCO3 and H2O so a physical change. However, if we add a piece of sodium metal to the water, we see a fizzing, the Na reacts with the water to form hydrogen gas, which may or may not burst into flame depending upon how hot it gets, that is a chemical change because we are decomposing the water into H2 gas while the Na metal is transformed into NaOH.
2Na + 2H2O ==> H2 + 2NaOH

Answer 2

Awesome explanation! Thank you

Answer 3

is it really even a physical change? I mean, the CaCO# just sits there in the water, so what has changed?

Answer 4

The addition of CaCO3 to H2O is a physical change. You may argue that a "change" didn't take place but it did technically. The environment for CaCO3 changed from a solid surrounded by air to an environment of a solid surrounded by water. So the ACT of adding CaCO3 to water is a physical change because the surroundings have changed. Certainly it can't be classified as a chemical change because the materials did not change.