C1.11a Indigestion remedies: Student brief Practice Controlled Assessment This practice controlled assessment is about indigestion remedies. Stomach pains are often caused by indigestion, when the stomach produces too much acid. Indigestion remedies contain substances that neutralise the excess acid in the stomach to make you feel better. You are going to test the hypothesis that indigestion remedies bought from a chemist are better than using baking powder or bicarbonate of soda. Plan an investigation to find out if indigestion remedies bought in a shop are better than chemicals found in the kitchen cupboard.
Part A: Planning How to attempt the task: You must produce a plan. The plan must include: •
an explanation of which equipment you need to complete the task. You may want to draw a diagram of how the equipment will be set up
•
which variable (or variables) you will change and which you will keep the same
•
which measurements you should make to test the hypothesis, explaining how these will test the hypothesis, and including the number and range of measurements
•
any risks that are linked to the practical task and how you can reduce these to make your practical task safer.
You should check that the overall plan is clear and will produce a range of results that will test the hypothesis.
Part B: Observations You are going to test the hypothesis that indigestion remedies bought from a chemist are better than using baking powder or bicarbonate of soda. You will test this hypothesis using your own method from Part A. You should also collect some secondary evidence on indigestion remedies.
How to attempt the task: You should decide on the number and range of measurements you will make Complete the practical task, recording your measurements clearly and accurately Collect some secondary evidence on this task Comment on the quality of the source of this secondary evidence.
Part C: Conclusions You will need your primary and secondary evidence from the Part B: Observations task and information about the method you used.
How to attempt the task: You must process your primary and secondary evidence from Part B and present these, using mathematical processes if relevant. You must produce a conclusion in which you: •
review all of the primary and secondary evidence, then identify and deal with any anomalies
•
draw conclusions from this processed evidence to prove or disprove a hypothesis
•
show how the data supports the conclusion
•
explain how you might change the method if you were going to repeat the investigation
•
describe the primary and secondary evidence you might collect to extend your investigation and say why you would collect it.
© Pearson Education 2010. Edexcel GCSE Science Activity Pack This document may have been altered from the original.
C1.11b Indigestion remedies: Observations Practice Controlled Assessment You are going to investigate the hypothesis that indigestion remedies bought from a chemist are better than using baking powder or bicarbonate of soda. You will be given the following equipment/resources: indigestion remedies, bicarbonate of soda, baking powder, calibrated pH meter and probe, stopclock, 1 M hydrochloric acid, beakers, small measuring cylinder, pestle and mortar, distilled water, teaspoon, stirring rod, eye protection
Health and safety Put on eye protection. Do not taste any of the remedies.
Follow these instructions when carrying out the practical: 1
If you are using an indigestion tablet, use the number of tablets or the quantity of remedy recommended on the packet. If you are using baking soda or bicarbonate of soda, use one teaspoon full.
2
If the remedy you are testing is in the form of tablets, crush the tablets.
3
Add the remedy to 50 cm3 of distilled water in a beaker and stir.
4
Use a pH probe to find the pH of the mixture. Record the pH when the number has stopped changing.
5
Add 10 ml hydrochloric acid and stir the mixture. Record the pH every 10 seconds until it has stopped changing, while still stirring the mixture.
6
Repeat steps 2 to 5 with the other indigestion remedies.
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C1.11c Indigestion remedies: Recording results Name
Practice Controlled Assessment
Class
Date
Carry out the investigation on Worksheet C1.11b Indigestion remedies: Observations and use this sheet to record your results and draw a conclusion.
Recording your results 1
Record your data in this table. Remedy Amount of remedy used Time (s)
pH
pH
pH
pH
pH
0 10 20 30 40 50 60 70 80 90 100 110 120
Presenting data 2 3
What is the range of pH values? a Draw a line graph on the graph paper over the page. You will need to number the axes and label them. Use the range from question 2 to help you. Put the time on the x-axis and the pH on the yaxis. Draw the lines for all the remedies on the same graph. b
Draw a smooth line through your points.
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Sheet 1 of 2
C1.11c Indigestion remedies: Recording results
Considering your results/conclusions 4
Which indigestion remedy was the most alkaline?
5
a
With which indigestion remedy did the pH go the lowest when you added the acid?
b
Which indigestion remedy allowed the least change in pH when the acid was added?
6
Which is the best indigestion remedy? Explain what you mean by 'best'.
7
Have you confirmed or disproved the hypothesis? Explain your answer.
Evaluation 8
Was your investigation a fair test? Explain your answer.
9
How good is the quality of your data? Explain your answer
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Sheet 2 of 2