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Contributed by: New York State Education Department (NYSED)
Task: At this station, you will experiment to determine
which of three solutions is acidic and which is basic.
Materials:
- Solution filled disposable pipettes labeled A, B, and C
- Disposable pipettes with phenolphthalein
- Blue litmus paper
- Red litmus paper
- Red litmus paper
- Reaction transparency or plate
- Waste cup
- Paper towels
- Safety goggles
- Cassette case
- Water for cleaning
Background:
Phenolphthalein turns pink in a basic solution.
Blue litmus paper turns red (pink) when dipped
in an acidic solution.
Red litmus paper turns blue (purple) when dipped
in a basic solution. |
Directions:
- Put your safety goggles on. Do not taste or touch any solution.
Clean up all spills immediately.
- Before you are three unknown solutions; A, B, and C. Think carefully
about an experiment you could do to determine which of the three
solutions is acidic and which is basic. You may use any or all
of the three indicators given to you.
- In the space below, describe the procedures you will follow
in conducting your experiment.
_______________________________________________________________
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- CARRY OUT YOUR EXPERIMENT.
- Record your color observations in the data table below.
| Indicator |
Solution A |
Solution B |
Solution C |
| Blue Litmus |
|
|
|
| Red Litmus |
|
|
|
| Phenolphthalein |
|
|
|
- Wash the plate or reaction transparency with water and dry with
a paper towel. Throw away any garbage into the waste cup.
- Using the data you have collected and the background information,
which solution is acidic?
_______________________________
In the space below, explain the reason for your answer. Refer
to Tables 1 and 2.
______________________________________________________________
______________________________________________________________
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- Using the data you have collected and the background information,
which solution is basic? _______________________________
In the space below, explain the reason for your answer. Refer
to Tables 1 and 2.
______________________________________________________________
______________________________________________________________
______________________________________________________________
NYS Alternative Assessment in Science Project
Copyright, April 1996
The State University of New York
The State Education Department
Albany, New York 12234
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