pandascienceolympiad wrote:Birdmusic wrote:Hi, I'm new to this event (and chemistry in general), so I have a couple of questions.
1) When my partner and I mixed iodine with flour mixed with water or cornstarch mixed with water, it didn't turn dark blue, any ideas why? We tried increasing the amount of water, flour/cornstarch, and iodine, but nothing happened still.
2) If one powder in a mixture dissolved and another didn't, how would you know? Wouldn't the water just be cloudy if one dissolved? Also, how would you know whether only one thing reacted with the HCl and iodine or both reacted?
1) Try to not mix the flour or cornstarch in water first. Also, your solutes and solvents might be old, try using newer ones.
2) Try looking at the mixture under a microscope first, and try and come up with possible powders it could be based on your results
Thank you! We got a new KI, and it seems to work much better.