ChemLab8.docx - Detection of Ions Students will be provided with an aqueous solution containing any combination of five anions or cations Available will

ChemLab8.docx - Detection of Ions Students will be provided...

This preview shows page 1 - 3 out of 6 pages.

Detection of Ions Students will be provided with an aqueous solution containing any combination of five anions or cations. Available will be known samples of each of the possible anions or cations and all the required supplies or chemicals needed to perform the evaluations for each. Students will be graded on their ability to determine the correct composition of the unknown solution with regard to which ions are present. Procedure: 1. Do the analyses for each ion in the order presented below 2. Do each analysis with the "known" solution first to note the observation expected to happen when the ion is present*. 3. Do the analysis of the "unknown" immediately after the analysis of the "known" to determine whether or not the “unknown” contains that specific ion. 4. Dispose of any chemical waste generated as directed. 5. Complete the Data Form.
Image of page 1

Subscribe to view the full document.

Test for the Presence of Ammonium Cation (NH 4 + ) Ammonium cation is treated with OH -1 to generate a small amount of ammonia gas by the following reaction: NH 4 +1 (aq) + OH -1 (aq) → NH 3 (g) + H 2 O (l) If the NH 3 contacts moistened red litmus paper, the reverse reaction occurs producing OH -1 resulting in a change in litmus paper color from red to blue. This color change is evidence of the presence of the ammonium cation. Procedure 1. Clamp a large test tube near its mouth vertically to a ring stand. 2. With the test tube vertical add 20 drops of the solution to be tested* to the test tube by an eye dropper and 40 drops of 6M sodium hydroxide (NaOH). Take care to avoid placing any liquid near the mouth of the test tube, or you will get a falsely positive result. *Solution to be tested for “known” will be the cation or anion of interest in the test and will be labelled as such (eg. NH 4 + ). In the case of testing for “unknown” it will be the solution labelled as “unknown”. All other steps in the procedure remain the same. Follow this instruction for all the ions.
Image of page 2
Image of page 3
  • Fall '14
  • Tuscono

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes