Experiment 7 lab report
1. Ken McFarland “Chemical Reactions and Identification of a Chemical Compound”, CHEM
1130, TA - Nastaran Marzijarani, Section 108, Room 1871, Will Brubacher, Thurs. 2:00 pm
1. Purpose of Experiment: This experiment is to learn how to classify chemical reactions and
to use them to identify an unknown solution of ions.
2. Procedure:
Fill A1 half full of NnOH, and B1 – E1 with distilled water. Add one drop of
phenolphthalein to each well. Draw all of the solution in A1 up into a dropper, and then
replace it in A1. Do the same thing with the water in B1 – E1, in order, without rinsing the
dropper between wells.
Fill each of the first 22 wells half full of one of the 22 solutions given, in order. You should
also have three breakers, A B and C. A and B should be 250 mL beakers of ddistilled water,
and C is a 400 mL waste water beaker. Use these to rinse your dropper between each
solution. Place 1 drop of your reference solution in 22 of the indents in the lid of the well
plate. To each drop of your unknown, add a drop of the corresponding solution from that well
in the well plate, and record any reactions that occur in your notebook. After you are done,
use your data to find all the classmates that have the same unknown solution as you, and
share data to identify any inaccuracies.
Do a flame test for your unknown, and the three solutions you were assigned to compare.
Record the color in your notebook. Test the conductivity of your solution, and the
conductivity of the three solutions you were assigned. Record weather they are strong, weak,
or do not conduct at all in your notebook.
Compare each of the 22 reference solutions with the other 21 solutions, and make a table of
the results. You will not compare all 22 of the solutions yourself, the instructor will assign
you three solutions to test, and the entire class will make a single table. If you have any
conflicting results, redo that one to check them. Use the resulting table to identify wich one
of the 22 solutions your unknown is. Be prepared to explain why.
3. Observations, Results and Data Sheets: See attached data sheet.
4. Questions:
1. Copper II Nitrate and Sodium Carbonate contained a large number of ions, shown by the
fact that there were many reactions with those two solutions. Solution 2 (acetic acid) did
not have any reactions at all, so there were no ions in it at all.
2. Barium Chloride and sulfuric acid are strong electrolytes, and litmus solution and sodium
hydroxide are weak electrolytes.
3. KI => K+ + I4. CuSO4 + 2KI => K2SO4 + CuI2
Cu2+ + SO42- + 2K+ 2I- => 2K+ + SO42- + CuI2
Cu2+ 2I- => CuI2
2KI + Cu(NO3)2 => 2KNO3 + CuI2
2K+ + I- + Cu2+ + 2NO3- => 2K+ + 2NO3- + CuI2
Cu2+ + I- => CuI2