Name
Date
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Honors Chemistry - Unit 4 Activity and Demonstration
Exploring Matter
Part I—Pure Substances and Mixtures
Procedure
1.
Fill a 50-mL beaker about half full of water.
2.
Add a pea-sized scoop of sugar to the water and swirl carefully then record
your observations in A.
3.
Fill a second 50-mL beaker about half full of ethanol.
4.
Add a pea-sized scoop of sugar to the ethanol and swirl carefully then record
your observations in B.
5.
Sketch particle diagrams in C to represent the contents beaker A and beaker
B.
6.
Fill a third 50-mL beaker with 10 mL of water, add a drop of food coloring
and swirl. Carefully add ethanol to the beaker to the 20-mL mark then
record your observations in D.
7.
Add a pea-sized scoop of sugar to the ethanol/water mixture and swirl
carefully then record your observations in E.
8.
Sketch particle diagrams in F to represent the contents of the ethanol/water
mixture and of the ethanol/water/sugar mixture.
9.
On the watch glass add a small scoop of salt and a small scoop of sand,
carefully mix with a splint then record your observations in G.
10.
Dispose of the contents of the beakers and the watch glass in the
appropriately labeled containers and clean the glassware thoroughly.
Observations
A Sugar/water
B Sugar/ethanol
C Particle diagrams
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D Ethanol/water
E Sugar/ethanol/water
F
Particle diagrams
G Sand/salt
Discussion Questions
1.
Define and list some examples of physical properties of substances.
2.
How could you separate the mixture of sand and salt? (Hint: What do you
know about water and sand? What about water and salt?)
3.
Based on your observations, what is the difference between a pure substance
and a mixture?
4.
What do these observations tell you about the properties of mixtures?
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5.
Is it possible to separate the mixture of water and ethanol? What would you
have to consider?
6.
If ethanol has a boiling point of 78.4 oC and water has a boiling point of 100.0
°C, what do you think the boiling point of a mixture of water and ethanol
would be? Remember that this is a mixture.
7.
Sketch a heating curve for the mixture water and ethanol. Would there be
plateaus? If so, where?
8.
Look up methods of mixture separation in your textbook and make a list
complete with a description of each technique. You must discuss a minimum
of three techniques.
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Part II—Elements and Compounds
Procedure
(Note – all magnet tests from outside the container)
1.
Obtain a container of iron and observe it closely. As you observe it, be sure to
smell it and test it with a magnet. Record your observations in A.
2.
Obtain a container of sulfur and observe it closely. As you observe it, be sure
to smell it and test it with a magnet. Record your observations in B.
3.
Obtain a container of iron/sulfur sample 1 and observe it closely. As you
observe it, be sure to smell it and test it with a magnet. Record your
observations in C.
4.
Obtain a container of iron/sulfur sample 2 and observe it closely. As you
observe it, be sure to smell it and test it with a magnet. Record your
observations in D.
5.
Sketch particle diagrams of iron/sulfur sample 1 and iron/sulfur sample 2 in
E.
Observations
A Iron filings
B Sulfur
C Iron/sulfur sample 1
D Iron/sulfur sample 2
E Particle diagrams
Discussion Questions
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9.
What happens when you pass a magnet over each of the iron and sulfur
samples?
10.
Propose an explanation for the results of each magnet pass. In other words,
explain what is different about the two samples. Justify your conclusion.
Electrolysis of Water – Demonstration
11.
Sketch and label the Hoffman Apparatus.
12.
At what electrode is gas accumulating faster?
13.
What do you notice about the ratio of volumes of gas collected?
14.
What do you think is happening to the liquid water? What is causing this
change?
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16.
What do you observe during the splint test with the gas that accumulated
faster?
17.
What do you observe during the splint test with the gas that accumulated
slower?
18.
Comment on the energy input(s) and output(s) during this demonstration.
Notes for Video – Ring of truth, Atoms
Summary
Write a summary of what you learned about substances, mixtures, elements and
compounds in the space below.
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