September 28, 2012
Experiment 4: Physical and Chemical Properties
PURPOSE: Observe physical and chemical properties of pure substances.
1. Place small amounts of a material into 4 test tubes.
2. Observe and record the color and scent of the material.
3. Take one of the test tubes and hold it over a flame using a clamp. Record any reaction the material has to heat.
4. Take a second test tube and fill it ¼ of the way with cold distilled water. Record how much of the material dissolves.
5. Heat the water over a flame to boiling. Observe again and record how much of the material dissolves. 6. When the solution cools, transfer a drop of the solution onto red and blue pieces of litmus paper. Record any color changes for both pieces.
7. Take a third test tube and add a few drops of HCl 6M to the material and stir. Record any observable reaction.
8. Take a fourth test tube and add a few drops of NaOH 6M to the material and stir. Record any observable reaction.
9. Thoroughly clean each test tube and repeat steps 1-8 for each other material.
PRE-LAB QUESTIONS: N/A
DATA AND OBSERVATIONS:
Data Table 1: Properties of Pure Materials
Cold H2O heat Formation No of white dissolution solid
Litmus test No change Mg
Turns black No dissolution No dissolution No change Zn
No dissolution No dissolution No change MgO
Red turns blue
Melts, turns black
No dissolution No dissolution No change Cu(NO3)2
Melts, turns green
Dissolution Dissolution Blue turns red
No change Dilute HCl
No observable reaction
Vigorous bubbling, fumes, generates heat, some material consumed, white solid precipitates, cloudy liquid No obserNo vable obserreaction vable reaction
No bubbling observable reaction Slightly light No green, obserdissolves vable reaction
Slightly bubbling, soluble, turns lighter turns green, blue, completely blue dissolves to liquid clear liquid
No clear green obserliquid vable reaction Cannot tell
to what tell to extent it what dissolves extent it dissolves CALCULATIONS AND ADVANCED STUDY QUESTIONS:
A. Did you observe any chemical changes in this experiment?
Yes, there were chemical changes when a chemical was heated or when an acid or base was introduced.
B. What evidence did you use to decide that something was a chemical change?
I think that a change that cannot be reversed is a chemical change. A good indicator for me was when the color of the