How do you figure out mixtures
First of all, there are 3 nonmetals which can never be mixed in this event: yeast, vitamin C, and sodium acetate. That being said, everything left is neutral or basic and non-biological.
The key to finding the components to a mixture is to react each off individually. If there appears to be a powder and a crystalline component, add HCl or iodine to a sample. If the iodine turns blue, finding the first component will be straightforward because you will only need to find the pH of the mixture with water. A more neutral pH will mean that it's flour; a more basic pH will mean cornstarch. If the iodine fizzes (and the HCl), then you have Alka-Seltzer. A fizz with only the HCl means the component is either CaCO3 or NaHCO3. Once again, a pH test will show the difference: a neutral pH means calcium carbonate, and a basic pH means baking soda. No reaction means gypsum. To find the crystal, test for solubility. Sand will not dissolve, whereas salt and sugar will. The difference between the latter two is that salt has cubic crystals, and sugar has irregular crystals.
Two crystals is fairly easy because you can skip the HCl and iodine and go straight for solubility. Once again, a component that does not dissolve is sand, and a component that does is either salt or sugar, which can be differentiated by crystal shape. If both dissolve, you have salt and sugar (probably the single most common mixture in this event).
For two powders, test with iodine first, then HCl if not all of the mixture fizzed or turned blue, and finally pH if needed. Go off of the information above to find each, and use logic if two things react at once.
Hope this helps!
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