Page 27 - Curriculum Visions Dynamic Book

 If you keep blowing through the straw,
the solution quickly goes clear again because the additional amount of carbon dioxide reacts with the calcium carbonate to produce soluble, and colourless, calcium bicarbonate, just like the rainwater and limestone described on page 13.
EQUATION: Calcium carbonate to calcium bicarbonate
precipitate: tiny solid particles formed as a result of a chemical reaction between two liquids or gases.
solution: a mixture of a liquid
and at least one other substance (e.g., saltwater). Mixtures can be separated by physical means, for example, by evaporation and cooling.
Calcium carbonate + water + carbon dioxide ➪ calcium bicarbonate CaCO3(s) + H2O(l) + CO2(g) ➪ Ca(HCO3)2(aq)
 Boiling the colourless solution will turn the solution cloudy again because calcium bicarbonate is not stable in hot water and the bicarbonate changes back to calcium carbonate, which is insoluble.
EQUATION: Change from calcium bicarbonate solution to calcium carbonate
Calcium bicarbonate solution ➪ calcium carbonate + carbon dioxide + water
Ca(HCO3)2(aq) ➪ CaCO3(s) with heat
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+ CO2(g) + H2O(l)