Chemicals in Solution - Unknown Example
You are given three vials containing solutions numbered 1, 2 and 3. They contain lead nitrate, nitric acid and lithium carbonate but, in this case, we do not know which is which. To determine their identity we should set up a table and perform a set of experiments similar to those we did with the known solutions. The results are:
|
| 1
| 2
| 3
|
| 1
| -
| white precipitate
| no reaction
|
| 2
| white precipitate
| -
| bubbles
|
| 3
| no reaction
| bubbles
| -
|
There are many strategies to determine which solution is which from this data. One is:
From the known data we see that lithium carbonate formed a white precipitate when mixed with one of the reagents and bubbles when mixed with the other. Therefore, solution 2 must be the lithium carbonate solution since it formed a white precipitate when mixed with solution 1 and bubbles when mixed with solution 3. Further, since we know that bubbles were formed when lithium carbonate was mixed with nitric acid, solution 3 must be the nitric acid solution. This means that solution 1 must contain lead nitrate.
This completes the background material. Proceed to the prelab.
