This experiment was performed to strive to find the identity of certain solutions through chemical reactions, and the process of reasoning and putting puzzle pieces together. The experiment was performed, and data was collected. Certain clues were used to put names to unknown solutions. Introduction:
During chemical changes, atoms rearrange, transforming the original substances into different substances.1 When a chemical change occurs it creates a visual change more often than not. These changes include precipitate (ppt) that forms which is an insoluble solid which remains suspended in the solution or sinks to the bottom and may be colored. A gas can evolve and appear as bubbles that effervesce from the solution and can give off an odor. Another - heat is evolved or absorbed. This will be indicated by a change in temperature of the reaction mixture and is to be detected by touching alone or by using a thermometer. Lastly, there can be a change in color.
Generally a chemical change occurs when two different substances mix and the reaction given off is very distinct to that specific combination of substances. Sometimes two substances create no change thats visible and can be labeled as no reaction (NR). Not all chemicals that exist will chemically change with each other. Without chemical changes some substances wouldn’ t exist. Today we tested to see if we could determine based off our observations which substances were what. Since each reaction is unique to its substance it should be relatively easy to determine which unknown chemical is what. Experimental Procedure:
To begin the experiment we had 12 compounds at our lab station. They are: Calcium Chloride (CaCl2), Hydrochloric Acid (HCl), Lead(II) Nitrate (Pb(NO3)2), Magnesium Sulfate (MgSO4), Potassium Iodide (KI), Silver Nitrate (AgNO3), Sodium Carbonate (Na2CO3), Sodium Sulfate (Na2SO4), Strontium Nitrate (Sr(NO3)2), Zinc Nitrate (Zn(NO3)2), and Sodium Hydroxide (NaOH). First two separate charts were created - one being a chart labeled “Known Solutions” and the other labeled “Unknown Solutions”. The first chart was each solution, written out, and it’s reaction with another solution, all being known and identified. The second chart was labeled generically as 1,2,3, etc. The known solutions (although used for both charts, are only for sure known in the first part of the experiment). After all solutions were located, one known solution was chosen, and three drops of that solution were placed in each eyelet of the plastic well, as a base. Next, each one of the other eleven solutions were placed in the plastic well - three drops in each eyelet - and mixed by a toothpick with the base solution. After each eyelet was mixed, the result was recorded in the “Known Solutions” chart. That process was repeated twelve times. For the “Unknown Solutions” experiment, the same exact process was repeated. The only difference was that numbers replaced solution names on the charts.
Although a few of these were harder to decide than others, the unknown solutions were pieced together, and chemical names replaced the numbers.
1 - MgSO4
2 - Zn(NO3)2
3 - Na2SO4
4 - HCl
5 - KI
6 - Pb(NO3)2
7 - Na2CO3
8 - CaCl2
9 - NaOH
10 - AgNO3
11 - Sr(NO3)2
12 - CuSO4
Unknown solution 1 was concluded to be MgSO4 because of a color change that turned paint white. Solution 2 was concluded to be