College Level: Principle Of Biology I (Online)
Water, pH, and Buffers
Hands-on labs, inc. Version 42-0136-00-01
Lab Report
PHOTOS – Include two digital photos with your lab report, either as separate attachments to an e-mail or paste into your document.
1. Photo #1 – Take a photo of the celery after it has been sitting for at least 4 hours.
Get close enough to see the results
2. Photo #2 – Take a photo of the HORIZONTAL needle observation.
Be sure you are close enough to see the needle and how it is relative to the water.
3. Photo #3 – Take a photo of your test results –
the layout of the commercial and homemade pH papers side by side
after dipping into each well. –It matches table #5
(This is the paper towel with the 12 numbers on it, with the papers beside the well #.)
Exercise 1: Water and its Unique Properties
Part I
|
Data Table 1: Needle Observations |
|
| Vertical: | Horizontal: |
Part ii
|
Data Table 2: Paper Clips Needed to Break Surface Tension |
|
| Hypothesis: | Result: |
|
Paper clips |
Paper clips |
Experiment
Water, ph, and Buffers
96
©Hands-On Labs, Inc.
www.LabPaq.com
Part iii
|
Data Table 3: Drops of Water |
|
| Hypothesis: | Result: |
Questions for parts i, ii, iii
A. How did the experiment in Part I demonstrate surface tension? Use your experiment
observations when answering this question.
B. In Part I, when adding the needle to the water, which approach worked best to balance the
needle on the water—the vertical or horizontal placement? Explain your answer.
Part iV
Data Table 4: Part IV Observations
Observations:
Question for part IV
A. How did this activity demonstrate capillary action? Explain your answer using your experiment results and observations.
Exercise 3: Testing Common Household Materials
for pH Values
Observations
|
Data Table 6: Analysis of Results |
|||
|
Well plate |
item tested |
Acid/B ase/ Neutral? |
Explanation: |
|
1 |
HCl (hydrochloric acid) |
||
|
2 |
NaOH (sodium hydroxide) | ||
|
3 |
Distilled water |
||
Questions:
A. Compare and contrast the results between the commercial and homemade pH test strips. Which test strips were more accurate? Explain your answer.
B. Why is the pH scale important in science? Give several examples of scientific applications.
C. What information about a chemical can be inferred from knowing its pH value?
D. If a chemical has a pH of 3, how could you change its pH value to be more basic?
Exercise 4: Buffers in a Living System
Observations
|
Data Table 7: pH Change of Buffered and Unbuffered Solutions |
||
| Unbuffered solution | Buffered solution | |
| Initial pH | ||
| + 3 drops HCl | ||
| + 6 drops HCl | ||
| + 9 drops HCl | ||
| + 12 drops
HCl |
||
| +15 drops HCl | ||
| +18 drops HCl |
Questions:
A. Analyze the results of your experiment. Did the buffer resist changes in the pH? Explain your
answer using your experiment results.
Experiment
Water, ph, and Buffers96©Hands-On Labs,Inc.www.LabPaq.com
Water, pH, and Buffers
Hands On labs, Inc., Version 42-0136-00-01
Lab Report
PHOTOS
–Include two digital photos with your lab report, either as separate attachments to an e-mail
or paste into your document.
1.
Photo #1
–Take a photo of the
celery after it has been sitting for at least 4 hours.
Get close enough to see the results
2.Photo #2–Take a photo of the HORIZONTAL needle observation.
Be sure you are close enough to see
the needle and how it is relative to the water.
3.Photo #
3–Take a photo of your test results
–the layout of the commercial and homemade pH papers side by side
after dipping into each well.
–It matches table #5
(This is the paper towel with the 12 numbers on it, with the papers beside the well #.)
Exercise 1: Water and its Unique Properties
Part I
Data Table 1: Needle Observations
Vertical:
Horizontal:
Part ii Data Table 2: Paper Clips Needed to Break Surface
Tension
Hypothesis:
Result:
Paper clips
Paper clips
Experiment
Water, ph, and Buffers96 ©Hands-On Labs, Inc., www.LabPaq.com
Water, pH, and Buffers
Hands-on labs, inc. Version 42-0136-00-01
Lab Report
PHOTOS – Include two digital photos with your lab report, either as separate attachments to an e-
mail or paste into your document.
1. Photo #1 – Take a photo of the celery after it has been sitting for at least 4 hours.
Get close enough to see the results
2. Photo #2 – Take a photo of the HORIZONTAL needle observation.
Be sure you are close enough to see the needle and how it is relative to the water.
3. Photo #3 – Take a photo of your test results –
the layout of the commercial and homemade pH papers side by side
after dipping into each well. –It matches table #5
(This is the paper towel with the 12 numbers on it, with the papers beside the well #.)
Exercise 1: Water and its Unique Properties
Part I
Data Table 1: Needle Observations
Vertical: Horizontal:
Part ii
Data Table 2: Paper Clips Needed to Break Surface Tension
Hypothesis: Result:
Paper clips
Paper clips
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