Wednesday, April 16, 2008

Went over procedures for crystal test, acid test, flame test.
1. Look at crystals under the microscope and, in your data table, sketch the characteristic shape of the crystals.
2. Scrape the crystal in to a pile and add 1-2 drops of HCl. Check for fizz or no fizz. Enter results in data table.
3. a. Light alcohol lamp.
b. Put spoon in flame with no crystal to check for flame color and burn off any contamination.
c. Rinse spoon in water.
d. Scoop up a part of the crystal with spoon, place in flame, check color of flame. Record in data table
e. Rinse spoon between each trial.

Went over data when everyone was done. Everyone should have a complete data table in their notebook.

Asked students to write in lab book how conclusive the various tests were. This will help when writing up the "Errors and Uncertainties" section of the sludge lab.

Some students did not get the expected flame colors and asked that I do the flame test in front of them so I did.

Density = mass/volume.

Assigned density problems 1-9 on page 56 of text book for homework but did start in class. I did problem 6 and students did problems 1,2,7 on board in front of class.