when I bubbled Alka selzer into limewater I believe all I saw was small bubbles form. is that correct and why? if not what should I have observed.
You should have seen "cloudy" water, indicating that Ca(CO3) had been formed in a reaction between CO2 and CaO
cloudy?? no bubbles??
When you bubbled Alka-Seltzer into limewater, the small bubbles you observed were likely carbon dioxide gas being released. This is the expected outcome because Alka-Seltzer tablets contain sodium bicarbonate (baking soda) and citric acid, which react when mixed with water.
To understand why these bubbles form, we need to consider the chemical reaction that occurs. The citric acid in Alka-Seltzer reacts with the sodium bicarbonate to produce carbon dioxide gas, water, and a salt. The formula for this reaction can be written as:
2NaHCO3 (sodium bicarbonate) + C6H8O7 (citric acid) -> Na2CO3 (sodium carbonate) + H2O (water) + CO2 (carbon dioxide)
The carbon dioxide gas is released in the form of bubbles. When you bubble the Alka-Seltzer tablet in limewater, the limewater (which contains calcium hydroxide) reacts with the carbon dioxide gas, forming insoluble calcium carbonate (a white precipitate) according to the following equation:
Ca(OH)2 (calcium hydroxide) + CO2 (carbon dioxide) -> CaCO3 (calcium carbonate) + H2O (water)
However, if you did not observe a white precipitate forming, it may be because the concentration of calcium hydroxide in your limewater was low or your observation time was too short. The formation of the white precipitate may take some time to become apparent.
In summary, when Alka-Seltzer is mixed with limewater, the reaction between the ingredients in Alka-Seltzer produces carbon dioxide gas, which forms bubbles. These bubbles can react with the calcium hydroxide in the limewater to form a white precipitate of calcium carbonate over time.