I have a question regarding the mixed powders. My school is unable to provide all of the materials needed for the competition so we can't test the mixed powder reactions. I tried to look around for some sources online, but most of it only covers the one-powder part. If there are two powders I can try to wing it and give an educated guess but on the rules it said "4a. At the state level, teams will have 15-18 unknowns and may have at least two mixtures containing 2-3
of the solids with asterisks." With three powders mix in, you have to be extra precise. Does anyone know any links or pages that can link me to a chart with two-three powders mix? Thank you, help is much appreciated!
Honestly, practicing random mixture tests Hands-on is the only way to really master identifying mixtures of any number of powders. In your case though I would suggest that you apply what you already know from single powders to help you ID what is in a mixture. I doubt there is any kind of accurate graph describing what a mixture would do so this is likely your only way of getting past mixtures. An example of applying single power reactions to a mixture would be, if you had a potential mixture of 3 that reacts to HCl and Iodine, then you can deduce that there is most likely flour/cornstarch for the Iodine to react, and baking soda, calcium carbonate (limestone), or alka seltzer causing the HCl to react. Your third powder could be any of the previously mentioned, or possibly gypsum or a grain. It really all comes down to how well you know how each substance reacts to each reagent, and how they look. Baking soda usually has a very fast and bubbly reaction while calcium carbonate has a very foamy and slower reaction. Another thing you can do is pour some of the mixture onto a towel or spot plate cover and, using any type of stick or rod, slowly flattening out the mixture allowing you to see some individual particles or grains from the mixture. You are correct that you need to be extra precise, but don't always jump to the conclusion that a mixture is 3 substances, since the test usually doesn't state how many powders are in each mixture. Good Luck at state, if you have any other questions feel free to ask. Hoped this helped you out
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