Chemical Dominoes
The goal of this project was to build a machine of chain reactions that incorporated 3 different chemical reactions within it
The Balloon
Description - Hydrochloric acid and Calcium carbonate react in an erlenmeyer flask with a deflated balloon attached over the top. The reaction creates carbon dioxide , inflating the balloon. As the balloon inflates it raises a lever, releasing a marble which triggers the next reaction.
Equation- 2 H+(aq) + CaCO3(s) --> Ca+2(aq) + H2O(l) + CO2(g)
Color Changing Liquid
Description - This step occurred when the lever was lifted and the string connected to the canister pulled the canister of liquid into the air and poured the liquid into the petri dish. When the film canister spilled the first clear liquid into the other clear liquid, it combined to turn yellow. The liquid in the canister is Potassium Iodine (KI) and the liquid in the petri dish is Lead Nitrate [Pb(NO3)2]. When they react, the structure of the mixture changes, and therefore its appearance changed as well; a bright yellow mixture. This is a double replacement reaction. The K switches with the Pb.
Equation - KI + Pb(NO3)2 -> PbI + K(NO3)2
Green Flame
Description - The mixing of ethanol and a salt when lit, produces a brilliant flame of any of the available colors. Our case contained a combustion reaction between cuprous chloride (CuCl2) and ethanol (C2H5OH ) which burned green, lit by a candle tipping into the watch glass containing them. This was the last step in our chemical domino sequence. It actually contained two reactions, a combustion reaction, and an excitement of electrons of the cuprous chloride. The first reaction is fairly straightforward - ethanol is lit and combusts with oxygen, producing water vapor and carbon dioxide. The second is a little more confusing. The reaction involved electrons of cuprous chloride getting excited and jumping onto a higher energy level. After a short interval, the electrons would fall back onto their original energy levels, releasing energy in the form of light, causing the flame to turn green due to the emitted light frequency.
REFLECTION
This project was very fun because it was a sort of throwback to freshman year when we made our rube goldberg machines. But this was a new challenge because there were chemical reactions involved to complete steps in the machine. My group made decisions and agreements with a significant amount of ease. The physical construction and completion of the chemical reactions and the consistency of them were by far the most difficult part. I learned the aspects of chemical reactions and creative thinking.
This project was very fun because it was a sort of throwback to freshman year when we made our rube goldberg machines. But this was a new challenge because there were chemical reactions involved to complete steps in the machine. My group made decisions and agreements with a significant amount of ease. The physical construction and completion of the chemical reactions and the consistency of them were by far the most difficult part. I learned the aspects of chemical reactions and creative thinking.