chemistry eassy 1

Add separately calcium nitrate solution (or calcium chloride solution) to each of the two solutions.

For sodium carbonate solution, a white precipitate of calcium carbonate is formed.
Ca^2+(aq) + CO3^2-(aq) → CaCO3(s)

For sodium hydrogencarbonate solution, there is no observable change because there is no reaction.

2009-12-05 20:37:30 補充：
The method supplied by Alan also works. However, the two equations are incorrect. The two equations should be:
2NaHCO3(s) → Na2CO3(g) + H2O(l) + CO2(g)
Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)

2009-12-05 20:37:45 補充：
The method supplied by Alan also works. However, the two equations are incorrect. The two equations should be:
2NaHCO3(s) → Na2CO3(g) + H2O(l) + CO2(g)
Ca(OH)2(aq) + CO2(g) → CaCO3(s) + H2O(l)

2009-12-05 20:39:48 補充：
Moreover, if excess CO2 is pass through the lime water, the lime water will become clear again. The equation is:
CaCO3(s) + CO2(g) + H2O(l) → Ca(HCO3)2(aq)

2009-12-05 20:40:02 補充：
Moreover, if excess CO2 is pass through the lime water, the lime water will become clear again. The equation is:
CaCO3(s) + CO2(g) + H2O(l) → Ca(HCO3)2(aq)

Firstly, dissolve them seperately in distilled water in test tubes. Secondly, connect the test tubes with delivery tubes to lime water in another two test tubes. Thirdly, heat them (Na2CO3->NaO + H2O + CO2)and observe the change of the colour of lime water. The set-up that the lime water change from colourless to milky( Ca(OH)2 + 2 CO2-> Ca(HCO3)2 ) is that sodium carbonate whilt the other is sodium hydrogencarbonate.