Determining if Density is an Extensive or Intensive Property

advertisement
H - 2011
Determining if Density is an Extensive or Intensive Property
Purpose:
Determine if density is an intensive or extensive property.
Concepts:
Density, uncertain and certain digits, significant digits, percent error, precision and accuracy, and
properties of matter including intensive and extensive.
(Bibliography: 3 or more sources MLA format)
Procedure, Data, and Calculations:
Design a lab to determine the density of a substance using the given material. When designing
your experiment consider the following:
 Measure mass with a balance
 Choose the best method to measure volume:
o Ruler: l x w x h
o Graduated Cylinder (Water Displacement Method): Vf - Vi
 Triplicate measurements
 Record all data with the correct number of significant digits based on the measuring
device used.
 When adding metals to graduated cylinders tip the cylinder to the side and slowly slide
the metal into the cylinder.
 Create a clear data table similar to the one below.
Sample
Zinc Pellets Zinc Rods
Mass 1
Mass 2
Mass 3
Ave Mass
Volume 1
Volume 2
Volume 3
Ave Volume
Ave Density

Zinc Blocks
Calculate:
Density:
D
m
V
Percent Error:

%Error 
measured  exp ected
100
exp ected
Conclusion
Aside from the normal requirements given in your lab report writing standards relate 2 of the
major themes of chemistry and real-world applications to the results of your experiment.

Discussion Questions for Density Lab
2011
1. What is density and how can you measure it?
2. At the molecular level, how would you describe density?
3. How does a steel ship float when a steel marble sinks?
4. What is the density of (room-temperature fresh) water? Under what circumstances will
an object float in water? Under what circumstances will an object sink in water? Support
your claims using observational evidence from your own experience.
5. Describe an experiment that would allow you to determine the density of a chair using
only the measuring equipment you have at home. Be as specific as you can. In other
words, what will you measure? How will you measure it? What calculations will you
have to do?
6. What are the two key factors that you could change to increase the density of a substance?
Give real-world examples of how you could change both of these characteristics and
change an objects’ density, in other words, cause an object to float instead of sink, or to
sink instead of float. (Temperature remains constant)
7. How does warming an object affect its size? Support your claim using observation from
your own experiences. Does warming an object make its density higher or lower? Why?
8. Which has a higher density, warm water or cold water? Why does one have a higher
density than the other?
9. Which has a higher density, fresh water or salt water? Why does one have a higher
density than the other?
Download