Qualitative analysis of ionic compounds
background [prelab assignment (20 points) due at the beginning of the lab]
if a precipitate forms by mixing the following chemicals in the corresponding row & column, then write "ppt" in the appropriate cell in the below table
sodium hydroxide sodium phosphate sodium carbonate sodium iodide sodium sulfate silver nitrate lead II nitrate cobalt II nitrate copper II nitrate barium nitrate iron III nitrate magnesium nitrate
use the above table in your prelab assignment & lab note book.
design a flowchart to identify each of the unknown ionic compound (in the below table) based on solubility rules and / or the solution's color (hint: all of the below copper II compounds are blue, while the other solutions are colorless) using the chemicals in the above table. include a copy of your flowchart in your lab notebook, so you can use it during the lab.
evaluate the reliability of the solubility rules
identify the unknown ionic compound in 3 samples based upon their reaction with other known solutions using solubility rules and your flowchart in the prelab assignment.
known aqueous solution (~ 0.1 M) of the chemicals shown in the above table
unknown aqueous solution; possibilities are shown below. There may be zero, one, or more than one choice from each column.
BaCl2 CuCl2 Na2CO3 Ba(OH)2 Cu(NO3)2 NaI CuSO4 NaOH Na2SO4
microwell plates [to view reaction]
methods / data analysis
student design: use flowchart in your prelab to identify your unknown sample.
if a precipitate does not form within a second or so upon adding the 2nd solution, consider it to be not forming a precipitate. record any color of the precipitate - it *might* be on the ap exam.
Content of lab report [
40 25 points; no revision for this lab report ]
data / observations (
reproduce the 2 copies of the table in your prelab assignment
fill-in your observations, i.e. ppt / no ppt / cloudy; color of ppt
fill-in if your observations are consistent or inconsistent with solubility rules determine frequency (i.e. %) of agreement / disagreement between your observations versus solubility rules. consider a cloudy (suspension) to be a ppt.
sequential observations of your analysis to identify the unknown samples
data analysis: (
based on the preceding table, what is the reliability of the solubility rules ? refer to your results to support your conclusion. [5 points]
identify the ionic compound in your 3 unknown samples; refer to your flowchart to support your conclusions, e.g. reproduce your flowchart and highlight the path to identifing the unknown ionic compound. [15 points]
example basis to identify cation & anion
simulation of experimental protocol to identify ions (see applets for "qualitative analysis of cation / anion)
lab activity source (examples): site 1 & site 2 [access 4 / 2009]
passsword protected content: flowchart; (no password protection) simulation