Measurement Quiz

1
Measurement Quiz!

• What is 2.341 4.2?
• (Use the correct number of sig. figs!)
• 2. What is 2.34x10-6 3.515x10-7
• (Dont worry about sig. figs)
• 3. Convert 7.8 km to mm.
• (Show D.A.)
• 4. How many seconds are in 15 years?
• (Show your dimensional analysis work!)
• 5. 3 x105 x 5x103

2
DENSITY AND BOILING POINT LAB

• LAB REPORT REQUIREMENTS
• PORTFOLIO EXPECTATIONS

3
GRADES

• Portfolio - worth 150 points
• Abstract and Materials (20 points)
• Due Wednesday (8/22)
• Results and Discussion (30 points)
• Due Monday (8/27)
• Final Drafts (100 points)
• Anticipated to be due on Wednesday (9/4)
• Best if typed!
• Must be attached to rough drafts

4
General Information

• Lab Reports should
• Be easy to read (Best if typed!)
• Convey essential information
• Be clearly labeled
• Contain the following parts

5
The Abstract

• A short description of what was done in the
  experiment
• Background information about the scientific
  concepts involved
• Brief description of results
• A good abstract is approximately 3 paragraphs
  that are seven to eight sentences each

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Hints on what to research

• Colligative Properties
• Properties that depend on the number of solute
  particles present
• The one we are focused on is called boiling point
  elevation
• Adding a solute to form a solution increases the
  boiling point of a solvent
• Applications
• Freezing-point depression (lowers temp. water
  freezes)
• Car applications

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Materials and Methods

• A list of procedures and equipment should be
  included in this section.
• The list does not have to be all inclusive but
  should cover the major pieces of equipment and
  important procedures followed in the experiment.
• The objective is to provide enough information so
  that the experiment can be duplicated.

8
Results

• Contains
• Data (tables, etc.)
• Graphs
• Calculations
• Statistical analysis
• Care must be taken to label each of these
  components
• The report should include salt and D.I. water
  boiling point graphs, and density calculations
• Also, the class average, average deviation, and
  percent error for the difference between salt and
  D.I. water boiling points should be clearly
  shown.

9
Discussion

• Discussion should
• Describe the precision and accuracy of the
  experiment
• Discuss all possible errors
• 2 Major Types
• One directional
• Examples Calibration, Instrumentation error
• Examples Mistakes such as not reading mass
  properly
• Contain a Brief Conclusion

10
Boiling Point Graphs

• Time vs. Temperature
• For both DI water and Saltwater solution
• Include variable and unit (Ex Time (s))
• Title
• Clearly labeled points
• Fill in curve

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Find Average Difference in BP
Example Difference in BP (ºC) 1 (Group 1) 2
(Group 2) 2 (Group 3) 3 (Group 4) 4 (Group
5) 5 (Group 6) 1 (Group 7) 18/72.6 ºC (Class
Avg.)

• Record the change in boiling point by other
  groups.
• Find the change by adding them and dividing by
  the number of groups.

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Find Average Deviation
Example Continued Deviation in BP (ºC) 2.6-1
1.6 (Group 1) 2.6-20.6 (Group 2) 2.6-20.6
(Group 3) 2.6-30.4 (Group 4) 2.6-41.4
(Group 5) 2.6-5 2.4(Group 6) 2.6-11.6 (Group
7) 8.6 /7 1.2ºC (Avg. Deviation)

• Find the difference between each groups change
  in temp. and the average change in temp.
• Add these values and divide by the number of
  groups to get the average deviation.

13
Percent Error

• Find the Percent Error of your personal data and
  the class average data.
• The True change in boiling point with addition
  of solute should have been an increase of 2.5ºC.
• Find the percent error
• Error True Value Experimental Value
• True Value

Continuing with Example Class Error 2.5-2.6
x 100 4 2.5