|MadSci Network: Chemistry|
Hi Ken. According to general solubility rules, you can predict that all alkali metal compounds are soluble in water (see any general chemistry text for a list of general solubility rules). This means that compounds containing lithium (Li), sodium (Na), potassium (K), rubidium (Rb) and cesium (Cs) are soluble in water. Salt (sodium chloride aka NaCl) and baking soda (aka sodium bicarbonate aka NaHCO3) both fall into this category, and should dissolve in water. Now, take some water and try to dissolve some measured quantity of each substance in it. According to the 74th edition of the CRC Handbook of Chemistry and Physics, at zero degrees centigrade (ice water), you can dissolve 6.9 grams of sodium bicarbonate in 100 mL of water (about 2/7 of the volume in a can of soda), but 35.7 grams of salt should dissolve in the same (separate) container of water. At 100 degrees centigrade (the boiling point of water at sea level...the boiling point of water drops a few degrees if you are at a high elevation like in Salt Lake City...approx 4500 feet above sea level), 39.1 grams of sodium chloride dissolve in 100 mL of water, so between these two temperatures, the solubility of salt in water isn't changing very much. At 60 degrees centigrade, only 16.4 grams of sodium bicarbonate dissolves in 100 mL of water. It would appear that salt is MORE soluble than baking soda over these temperatures. I'd guess that the salt is more soluble than baking soda because water is polar (the oxygen part of water can be thought of as being more negatively charged than the hydrogen parts) and salt is more polar than sodium bicarbonate. You might have heard the saying "like dissolves like"...very polar things dissolve best in very polar liquids. I hope this answered your question. Please feel free to email me if you have any further questions. (firstname.lastname@example.org) Best Regards, Mike Weibel
Try the links in the MadSci Library for more information on Chemistry.