In The Great White North Posted June 25, 2009 Share Posted June 25, 2009 How long could I expect the chemicals in a chem set to last? Which ones would "go bad" and which last forever (salt, baking soda?)? Would you expect the experiments to just fizzle if the chemicals were old? I have an old Smithsonian Microchem XM 5000 set. HomeScienceTools sells individual chemicals, so I could replace the ones that were too old without having to buy a whole new set. Quote Link to comment Share on other sites More sharing options...
Joan in GE Posted June 25, 2009 Share Posted June 25, 2009 that it depends on the chemical...the ones that will go bad are the ones that decompose with heat, water, or light.... So all those chemicals that react with water, if they are not well-sealed (eg sodium hydroxide), will absorb moisture and become one big glob or clumped (sign of problem). Many chemicals are sensitive to water... The heat sensitive ones, can even get damaged at room temperature over time.. Light sensitive ones are usually protected with colored glass or aluminum foil around the jar... Because of the desired shelf life of these kits, he thinks that most of the chemicals are probably relatively stable (and chosen for that), especially if they are unopened.... HTH, Joan Quote Link to comment Share on other sites More sharing options...
In The Great White North Posted June 25, 2009 Author Share Posted June 25, 2009 Thank you Quote Link to comment Share on other sites More sharing options...
Joan in GE Posted June 26, 2009 Share Posted June 26, 2009 a problem we had with some old sets that we bought used (if that is the case for you), was that I think whoever had used them was not careful about using clean utensils...So I think that some of the chemicals were no longer purely what they were labeled....then the experiments didn't work the way they should have. Being the frugal mom that I am, we would first do the experiment with the old chemicals, and then use the new chemicals (from Kosmos kit) if the experiment didn't work...Usually that solved the problem but not always. But as I read somewhere...it is important to try to figure out why an experiment did not work...so my children and I got practice. :) Quote Link to comment Share on other sites More sharing options...
In The Great White North Posted June 26, 2009 Author Share Posted June 26, 2009 I found it at the dump :001_smile: free. It was very dusty but appeared unused. Being the frugal mom that I am, we would first do the experiment with the old chemicals, and then use the new chemicals (from Kosmos kit) if the experiment didn't work.. That's what I'm hoping to do. Actually, I'm hoping to not have to buy any new ones, but that could be overly optimistic. Quote Link to comment Share on other sites More sharing options...
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