Pre Lab Questions Qualitative Analysis Of Sulfide Group Cations 1 Given The Very Low Value Of K For Cr Oh A Precipit 1 (88.61 KiB) Viewed 26 times
Pre Lab Questions Qualitative Analysis Of Sulfide Group Cations 1 Given The Very Low Value Of K For Cr Oh A Precipit 2 (75.32 KiB) Viewed 26 times
Pre Lab Questions Qualitative Analysis Of Sulfide Group Cations 1 Given The Very Low Value Of K For Cr Oh A Precipit 3 (87.06 KiB) Viewed 26 times
PRE-LAB QUESTIONS Qualitative Analysis of Sulfide Group Cations 1. Given the very low value of K for Cr(OH),, a precipitate of Cr(OH), would be expected if limited 6 M NaOH were added to the mixture of sulfide group cations in the first step of the procedure. Explain how and why the chromium remains in solution. 2. A solution may contain one or more of the sulfide group cations. When this solution is com- bined with NaOH (aq) solution, only a colorless solution is obtained with no precipitate evi- dent. Indicate whether each of the following cations is present, absent or undetermined. Is Cation Present, Absent or Undetermined? Cr Fe Mn Explain: Cation 3. Complete and balance the molecular equation for each of the following reactions. For each, give the total ionic equation and the net ionic equation as well. Indicate any precipitates which may form with (s). a. Fe(OH), (s) + 3HNO, (aq) → b. Fe(NO,), (aq) + 6KSCN (aq) → c. Mn(NO₂), (aq) + NaBiO, (aq) + H¹ →→
4. a. Write the complete electronic configuration for manganese (Z = 25), iron (Z = 26) and chromium (Z=24). Note that chromium's configuration is one of the systematic exceptions. b. Write the electronic configuration for Fe, Mn², and Cr". Fe³+ Mn² Cr³+ 5. Choose a reagent that will separate the cations in each of the following pairs. Pairs a. Mn²+ and Cr(OH)³*? b. Mn(NO₂), (aq) and Mg(NO), (aq) (Hint: Mg is a soluble group cation) Reagent That Will Separate the Cations
Rerecord data for this experiment: for each step you must record which reagent is added, then you record your observation, write chemical reaction for each step and indicate the phase for reactant and product. Also indicate which ones are soluble and which ones are precipitate. Part A-2 A-3 A-4 B C-1 Added Reagent C-2 C-3 C-4 Observation Chemical Reaction Soluble Precipitate 27
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