Paige Posted September 21, 2020 Share Posted September 21, 2020 If we are testing for molecules and I want to give the students an unknown substance among a bunch of known ones what's a good thing to use for the unknown substance? We're testing for sugars, starches, lipids, and proteins. I know it's a common lab but I have no teacher's manual and I took Chemistry too long ago to have any memory of it. If it's some big secret and the chemistry teachers of the world don't want everyone to know what people like to use, can you PM me. I just want a substance that will react well and be pretty obvious if they do it correctly. Quote Link to comment Share on other sites More sharing options...
Wheres Toto Posted September 21, 2020 Share Posted September 21, 2020 I do this in Chemistry and CSI classes. I use Borax, corn starch, baking soda, sometimes add a few others like sugar or baking powder and test with vinegar (reaction), iodine, and pH indicator. I do it at a point in the class where I will also ask for suggestions and they may suggest looking at solubility. I do another one where we test the properties of matter using sulfur, borax, epsom salts, sugar, salt, alcohol, vinegar, oil, and pH indicator (cabbage/anthocyanin) and test for solubility, pH, flammability (depending on age of the group), odor, appearance, etc. My older Chem classes we do the macronutrient testing and we use the list below with some variation if there are allergies in the class. We test for Lipids (ethanol to extract, look for globules and/or brown bag test), Proteins (Biuret Solution), Simple Carbohydrates (Benedict's Solution), Complex Carbohydrates (Iodine), Vitamin C (Indophenol). We also made french toast at the end of that class. 🙂 Honey Powdered sugar Potato Egg White Egg Yolk Apples Orange juice Milk Bread Cereal Apples Orange juice Milk Bread Cereal 2 Quote Link to comment Share on other sites More sharing options...
Wheres Toto Posted September 21, 2020 Share Posted September 21, 2020 I have a Chemistry Pinterest board if you are on there: https://www.pinterest.com/dottieanna29/stem-chemistry/ And the American Chemical Society has a free middle school Chemistry manual that is good. If you are doing older ages, it can be beefed up a little bit. 1 Quote Link to comment Share on other sites More sharing options...
Paige Posted September 21, 2020 Author Share Posted September 21, 2020 Here's the known substances they'll be testing- Water, simple sugar solution, orange juice, soda, diet soda, starch, olive or canola oil, heavy cream, and egg whites. What would you add for a mystery substance? Honey may be too easy to identify. Maybe I could make a cereal/water slurry? They're supposed to see how the known substances react to the testing agents (benedicts, iodine, sudan, and biuret) and then test the mystery one to see if they can figure out what it may be most like. Quote Link to comment Share on other sites More sharing options...
Wheres Toto Posted September 21, 2020 Share Posted September 21, 2020 That's a hard one since they all look pretty different. I do the "white powders" since they can't figure it out just by looking. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.