Honors Chemistry, Thursday, 10/6/16

What is the ground vs excited state of an electron?

            Element: SC3.g                                        

1. Due - Wave Problems WS

2. Ground vs Excited State of electrons

3. Energy Equation - Finish WS problems

4. PreLab - Flame Test - Prelab activity - Lab Thursday

5. HW - Finish prelab questions

Prelab questions:

1. Write out the electron configurations for each of the metallic ions to be tested in this investigation. Ba⁺², Cu⁺², Li⁺¹, K⁺¹, Sr⁺², Ca⁺², Na⁺¹
2. What does a flame test indicate about the energy changes taking place among the electrons in a metallic ion?
3. Explain why a metallic ion produces a characteristic color in a flame test, regardless of the compound used as the source of the ion.
4. What wavelengths correspond to the visible spectrum? Which color has the shortest wavelength? The longest?
5. What precautions should be taken when using 6.0M HCl?
6. Why is it important to use a clean nichrome wire for each test?

Procedure:

1. Put on your goggles and lab apron. Obtain a well plate and use a marker to label seven wells with the names of the known solutions. Put a dropperful of each known solution into its labeled well.
2. Put on your latex gloves. Obtain a beaker with about 10 mL of 6.0M HCl and a nichrome wire loop. Light the burner, and adjust the flame to low. CAUTION: Hydrochloric acid is corrosive to skin and clothing and its vapors are irritating to lungs and eyes. Avoid contact with the solution and inhalation of its vapors. Loose hair should be tied back or covered and bulky or loose clothing should be secured in some manner.
3. For each test, be sure that the nichrome wire is clean, so as not to contaminate the solutions. To clean the wire, first rinse it with distilled water, using  the wash bottle. Then dip it in the 6.0M HCl solution. Place it in the burner flame for a few moments. Determine the color of the clean nichrome wire in the flame. This is the color you should see after every trial.
4. Sodium has a very strong color, which may affect your other tests, so test the sodium solution last. Dip the clean nichrome wire in on solution. Place the wire in the burner flame and observe. Record your observations. Clean the wire and repeat this step with the next known solution until you have tested all seven solutions.
5. Obtain three unknowns from your teacher. Repeat step 4 for each unknown. Record your observations.
6. Turn off the burner. Clean up your work area and wash your hands before leaving the laboratory.