Estudiante

The Ten Test Tube Mystery

Sol Leon
Mrs. Paul
05/15/12
AP Chemistry

Objective:
To determine which solution is in each ten numbered test tubes using logical deduction as well as using knowledge learned in previous class experiments.
Materials:
Chemicals
6 M HCl
6 M NH3
3 M H2SO4
6 M NaOH
0.1 M Ca(NO3)2
0.1 M AgNO3
0.1 M Cu(NO3)2
0.1 M Al(NO3)3
0.1 M Ni(NO)3
0.1 m Pb(NO3)2Equipment
Rack Container
10 test tubes of solutions numbered from 1 to 10
1 mL pipettes, one for each solution
Distilled water
Well plate
Pre-Lab:
1. Construct the reaction matrix for your set of ten solutions using information in your chemistry text or in Appendix II & III:
| HCl | NH3 | H2SO4 | NaOH | Ca(NO3)2 | AgNO3 | Cu(NO3)2 | Al(NO3)3 | Ni(NO3)2 | Pb(NO3)2 |
HCl | | H |NR | H | NR | P, white, SN | NR | NR | NR | P, white, SA (Conc.) |
NH3 | | | NR | NR | NR | P, brown | P, royal blue, SN | P, white, SA | P, green, SN, SA | P, white, SA |
H2SO4 | | | | H | P, white | P, white | NR | NR | NR | P, white, SB |
NaOH | | | | | P, white, SA | P, brown, SN | P, light blue | P, white, SB | P, green, SA, SN | P, white, SB |
Ca(NO3)2 | | | | | | NR |NR | NR | NR | NR |
AgNO3 | | | | | | | NR | NR | NR | NR |
Cu(NO3)2 | | | | | | | | NR | NR | NR |
Al(NO3)3 | | | | | | | | | NR | NR |
Ni(NO3)2 | | | | | | | | | | NR |
Pb(NO3)2 | | | | | | | | | | |

Key:
NR – No Reaction
P – Precipitate formation
D – Precipitate dissolves
Color – Color of the solution or precipitate formed
H – Heat isevolved
SA – Precipitate is soluble in acid
SN – Precipitate is soluble in ammonia solution
SB – Precipitate is soluble in base.
2. Which solutions should you be able to identify by simple observations?
Ni(NO3)2 will be the only green solution. Cu(NO3)2 will be the only blue solution. NH3 will have a really strong horrible smell compared to the smell of the other solutions.
3.Procedures:
1. Put on Safety gear ex. Apron, hair tied up, etc. Grab the identified rack of test tubes from your teacher (the one that was assign to you) and place it on your lab station.
2. Label each pipette with its corresponding solution as well as label the well plate to indicate what reactions takes place in each plate before starting the experiment.
3. From observations, identify Ni(NO3)2and Cu(NO3)2 and write down your observations in the “Solutions That Were Identified Directly” data table.
* Note: Ni(NO3)2 will be the only green solution and Cu(NO3)2 will be the only blue solution.
4. Carefully open each of the remaining 8 unidentified test tubes and smell each of them to identify NH3. Write down observations in the “Solutions That Were Identified Directly” datatable
* Note: NH3 will have a really strong horrible smell compared to the smell of the other solution. The smell will make you gag.
5. Carefully open the test tube that contains Ni(NO3)2 and use the corresponding labeled pipette. Pipette about half of 1mL (which is more than enough to use maximum of two drops of the solution).
6. Drop one drop of Ni(NO3)2 solution inside a labeledwell of the well plate without poking or touching any sides of the well as well as any surroundings.
7. Carefully put back any remaining of the solution that’s inside the pipette back to Ni(NO3)2 solution test tube. Place back the pipette to its place. Close the test tube.
8. Repeat steps 5 – 7 with solution each of the remaining 7 unidentified solutions and react each of them withNi(NO3)2. Observe each reaction and pay extra attention for a GREEN precipitate formation.
9. Identify the used unknown test tube as NaOH for the reaction that produced a GREEN precipitate. Write identification in “Mixing Tests: First Series” data table.
10. Use identified NaOH test tube and follow steps 5 – 7 with the remaining 6 unidentified solutions to react each of them with NaOH. Observe...