HSC YEAR 12 WYONG TAFE
COMPULSORY PRACTICAL ACTIVITY
THE EFFECT OF DISSOLVED CARBON DIOXIDE ON THE PH OF WATER
Learning outcomes covered by this activity
P2 - carry out a firsthand investigation
P6 - explain how cells contribute to macro processes in organisms
P11 - identify and plan improvements to investigation plans
P12 - discuss the validity and reliability of data
P13 - identifies appropriate terminology an reporting styles to communicate information and understanding in
biology
P14 - draw valid conclusions from gathered data and information
P15 - implements strategies to work effectively as an individual or as a team member
H12 - evaluates ways in which accuracy and reliability could be improved in investigations
H13 - uses terminology and reporting styles appropriately and successfully to communicate information and
understanding
H14 - assess the validity of conclusions from gathered data and information
THE ACTIVITY
 You are to plan an experiment which demonstrates the effect dissolved carbon dioxide on the
pH of water.
 You are to choose the equipment for the experiment
 Carry out the experiment
 Record, interpret and use the data to form conclusions
MATERIALS
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Solid calcium carbonate
Dilute Hydrochloric Acid
Distilled water
100mL measuring cylinder
Test-tubes, one test-tube fitted with a cork and
bent glass tubing as shown
Test-tube rack
Clamps and retort stands
Plastic bag with rubber band to close it- a small
freezer bag would also be suitable
Universal indicator paper and a card to check to pH
Lime water solution (calcium hydroxide)
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METHOD
1. Choose the equipment from the materials and equipment provided and design an experiment to
show the effect of CO2 on pH of distilled water. You must demonstrate the effect of CO2 from
two different sources of CO2 on the pH of water.
2. Write down your experimental design and check it with your teacher.
3. Perform the experiment and record the data.
4. Try increasing the amount of CO2 and check it there is a further change in pH.
5. Interpret your data to make a conclusion about the answer.
6. Answer the questions.
QUESTIONS
What was the effect of CO2 on the pH of distilled water?
How does pH relate to hydrogen ion concentration?
From your knowledge of biology, explain how carbon dioxide changes the pH.
What sources of CO2 did you use?
Which of these sources is relevant to body physiology? Explain how it is made in the body.
Would the change in pH be dangerous for the body? Explain
If so, how does the body solve the problem?
What essential measurement did you have to make before testing the effect of CO2 on the water?
Why?
9. Having designed and performed this experiment, what do you think are the key points about it –
assume you are explaining it to another student who has not done it before.
1.
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8.
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MARKING SCALE
Your experiment will be marked on the following scale
TOPIC
P6,
H13
P2
P2,
P13,
P15,
H13
P12,
P14,
H13
H13,
H14
P15,
H12,
H13
MARK
Background information on the
macroprocesses in organisms
Experimental design- a diagram
of the experimental set up
Experimental write up with
detailed explanation of the how
the experiment was carried out
with aim, method, equipment
used, results clearly recorded
and a discussion of the results.
Draw conclusions from recorded
results. Answer the questions by
selecting and using appropriate
methods to acknowledge sources
of information
Evaluate the accuracy and
reliability of the results
Identify trends, patterns and
relationships as well as
contradictions in data and
information
Identify and explain hoe data
supports or refutes an
Identify ways to improve the
investigation
TOTAL
MARK AWARDED
4
1
5
4
4
2
20
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