Download and follow the instructions in file "Experiment_Qualitative_Analysis_Instructions" below. These have been provided as a MS-word .docx file or as a PDF file. You will be directed to use a website to complete an online simulation of the qualitative analysis experiment.
Experiment_Qualitative_Analysis_Instructions.pdfPreview the document
Online Lab Experiment Qualitative Analysis A. General Background to Qualitative Analysis Experiment Qualitative analysis is a method used for identification of ions or compounds in a sample. In many cases, qualitative analysis will also involve the separation of ions or compounds in a mixture. Examples of qualitative tests would include ion precipitation reactions (solubility tests) or chemical reactivity tests. The separation of ions is easily achieved by taking advantage of their solubility properties. The goal of this lab is to use qualitative analysis to identify which cations are present in an “unknown” mixture containing one or more of the cations Ag+ , Hg2 2+ and Pb2+ (known collectively as “Group I Cations”). In a lab simulation, you will use selective precipitation, which takes advantage of the differing solubility of these ions in different conditions, to separate these ions from the mixture and then confirm their presence or absence using selective chemical reactions. In the first part of the experiment you will use a qualitative analysis scheme with known solutions containing one or more of the group I cations to show how the ions behave and can be identified. In the second part, you will perform the same procedure with an assigned “unknown” and identify which of the group I cations is present or absent. B. Specific Background to this Experiment: Separation and Identification of Group I Cations. Download the file “Qualitative Analysis Lab 364” from the assignment. This contains a portion of a paper describing “The Chemistry and Qualitative Analysis of Cations: Group Separations and Separation of Group I Cations” Read the sections titled: “Background Information”,”I, Separating Group I Cations from Group II, III and IV Cations” and “III. Group I Cations (Insoluble Chlorides)” These sections contain a specific background and explanation of the use of selective precipitation and confirmation reactions to separate and identify group I cations (Ag+ , Hg2 2+ and Pb2+) in a mixture of cations. Note that the separation procedure we will use in the online lab simulation is generally similar to that described in this paper. However, the details of the confirmations are different and are described in the online lab simulation documentation (see below). Part C of these instructions contains information on how to use the online lab simulation. Part D of these instructions describes the experiments you should carry out. Part E contains instructions on postlab questions and how to submit your lab assignment. 2 C. Instructions for Online Qualitative Analysis Simulation. 1. Go to the following website: http://web.mst.edu/~gbert/qual/qual.html This site is called “Qualitative Analysis – Cations Group I” and contains an online simulation of a qualitative analysis experiment for group I cations. It was created by Prof. Gary Bertrand of the Department of Chemistry at Missouri University of Science and Technology (https://chem.mst.edu/) and we thank him for our use of this simulation. 2. Toward the top of the page you will see heading for “Discussion”, “Flow Sheets”, “Operation” and “Check Unknown”: a) Click on “Discussion”. A new page will open that contains a description of the experiment procedures and a suggested experiment to use known solutions. It is a good idea to print this page if you can so that you can refer to it at any time. b) Click on “Operation” at any time to see instructions on how the various parts of the virtual lab simulation work. c) Click on “Flow Sheets” to see a representation of the steps in the qualitative analysis scheme used to separate and identify group I cations. d) Click on “Check Unknown” when you are ready to see if you have correctly identified the cations present and absent in your sample. 3. Watch the powerpoint presentation found in the lab assignment. In this I will show you a run through of how the online QA lab simulation works. D.