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HIA International — Grade 8

Unit 1: Photosynthesis and the carbon cycle

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Unit 2: Properties of materials

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Unit 3: Forces and energy

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Unit 4: Maintaining life

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Unit 5: Reactivity

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Unit 6: Sound and space

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Unit 7: Genes and inheritance

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Unit 8: Rates of reaction

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Unit 9: Electricity

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Quiz

8.2 Investigating Acids And Alkalis

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Investigating Acids And Alkalis Checkpoint Chemistry quiz set 2: free practice for Cambridge Checkpoint (chemistry). Work through this Investigating Acids And Alkalis Checkpoint Chemistry quiz set 2 and get instant feedback on every answer. If you get stuck, review the 16.2 Investigating acids and alkalis lesson. More practice: Cambridge Checkpoint (chemistry) — all units. Syllabus: Cambridge Lower Secondary programme.

  • Questions count: 50
  • Passing grade: B+
  • Time limit:
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1.
Which statement correctly describes variable?
an investigation changing one variable while controlling others
a scale used to describe acidity and alkalinity
a statement supported by results
a factor that can change
2.
Amir works out his mean from trials 1–3 only. Why is it right to leave out the rough trial?
It was the first trial, and the first result of any test is always wrong
It is the largest value, and the largest value is always left out of a mean
It was done quickly to find roughly where the end point is, so it overshot
It used a different acid, so it measured a different dependent variable
3.
An advert claims: "The more you pay for an antacid, the more acid it neutralises." Do these results support the claim?
No – the cheapest tablet, R, neutralised the most acid
Yes – the most expensive tablet, S, neutralised the most acid
Yes – every brand neutralised at least some of the acid
No – a claim about price can never be tested by experiment
4.
Marco measured the pH of acid with a pH meter after adding the same antacid as a powder or as a whole tablet. How much longer did the whole tablet take to raise the pH to 5.0?
Dr Dabour Hub Academy - figure 1
3 minutes longer
7 minutes longer
2 minutes longer
4 minutes longer
5.
Each option pairs a word used to describe results with its meaning. Which pairing is correct?
Reproducible – similar results when others repeat the method
Accurate – the same result every single time you repeat
Precise – the result exactly matches the prediction
Repeatable – other groups got a different answer
6.
One of the means in the table has been calculated wrongly. Which one, and what should it be?
Bed B – it should be 5.8
Bed C – it should be 7.1
Bed D – it should be 4.8
Bed A – it should be 6.3
7.
Which statement correctly describes fair test?
a factor that can change
a statement supported by results
an investigation changing one variable while controlling others
a scale used to describe acidity and alkalinity
8.
Why should a pH probe be rinsed with distilled water and dried before it is moved to the next sample?
So that liquid from one sample does not change the next reading
So that the probe is neutralised and gives a reading of pH 7
So that the probe cools down after measuring an acid
So that the next sample becomes more dilute and safer
9.
Students want to know the pH of the water in a large pond. Which sampling method gives the most representative result?
Test one sample from the edge nearest the school, five times
Test one sample from the deepest point, as it is least polluted
Test samples from several places around the pond and find the mean
Test samples only from places where the water looks clearest
10.
Ruth will investigate how the concentration of an acid affects the volume of alkali needed to neutralise it. Which set of concentrations is best?
0.2 and 1.0 g per 100 cm³ only
0.2, 0.4, 0.6, 0.8 and 1.0 g per 100 cm³
0.2, 0.25, 0.3 and 0.35 g per 100 cm³
1.0 g per 100 cm³ tested five times
11.
Tomas says his graph shows that the mass of baking soda needed rises faster and faster as the volume of vinegar increases. What is the best evaluation?
Dr Dabour Hub Academy - figure 2
His x-axis scale is uneven; on an even scale the points lie on a straight line
He is correct, because the line gets steeper towards the right-hand side
He should have drawn a bar chart, because volume is a categorical variable
He is correct, but only because the baking soda was not weighed accurately
12.
Another class follows Nadia's method exactly but finds much larger volumes of alkali are needed for the same acids. What does this suggest?
Nadia's results must be correct, because she did the investigation first
The results are not reproducible, so the method or chemicals should be checked
The other class must be correct, because their numbers are larger
Reproducibility does not matter as long as each class did repeats
13.
Which of these is the FIRST step in the correct order?
identify variables
draw a supported conclusion
write a testable question
collect pH results
14.
Which step comes immediately after "identify variables"?
write a testable question
draw a supported conclusion
collect pH results
15.
Look at Olu's plan. Each option pairs a column with the type of variable it is. Which pairing is correct?
Type of fruit juice – control variable
Volume of juice – independent variable
Room temperature – dependent variable
Drops of alkali needed – dependent variable
16.
Which practical work belongs to Investigating Acids And Alkalis?
Compare metal reactions and use the hydrogen “pop” test safely under supervision
Use observations, precipitates, temperature change and gas tests as evidence of reaction
Relate neutralisation to antacids, soil treatment and industrial waste treatment
Plan and evaluate a fair test comparing acids, alkalis or neutralisation reactions
17.
Which solution is the most acidic, and which test shows this?
J – litmus paper shows it is the strongest acid of the four
K – both litmus papers show that it is strongly acidic
M – only universal indicator can show it is more acidic than J
M – blue litmus turned red faster than it did with J
18.
Which statement correctly describes conclusion?
a factor that can change
an investigation changing one variable while controlling others
a scale used to describe acidity and alkalinity
a statement supported by results
19.
A dropper releases drops of 0.05 cm³. Idris needed 36 drops of alkali to neutralise his acid. What volume of alkali did he add?
36 cm³ of alkali
0.72 cm³ of alkali
1.8 cm³ of alkali
7.2 cm³ of alkali
20.
Which row of the risk assessment has a control measure that is NOT safe?
Row 1 (hydrochloric acid)
Row 2 (sodium hydroxide)
Row 3 (filling the burette)
Row 4 (spilled acid)
21.
Which definition should be paired with variable?
a statement supported by results
a factor that can change
an investigation changing one variable while controlling others
a scale used to describe acidity and alkalinity
22.
Each option pairs something recorded in an acid–alkali experiment with the kind of data it produces. Which pairing is correct?
Brand of antacid – continuous data
Colour of universal indicator – continuous data
Volume of alkali in cm³ – continuous data
Concentration of acid – categorical data
23.
A pH meter was not calibrated and gave every reading 0.5 too high. Chen tested each sample three times. What effect does this have on his results?
Repeats become very spread out, but the means are still correct
The error cancels out when he calculates a mean of three readings
Only the first reading of each sample is affected, not the repeats
Repeats still agree closely, but every mean is 0.5 too high
24.
Kai tested a soil sample as shown. What pH should he record, and why did he wait before reading it?
Dr Dabour Hub Academy - figure 3
pH 4 – the brown cloudy colour just after shaking is the true result
pH 7 – waiting lets the indicator neutralise the soil acid completely
pH 6 – the soil had to settle so the liquid colour could be seen clearly
pH 6 – waiting lets the soil release all its acid into the air first
25.
Rosa's hypothesis is: "More concentrated acids need more alkali to neutralise them." Which result would count against her hypothesis?
The most concentrated acid needed the most alkali
Doubling the concentration doubled the alkali needed
The most dilute acid needed the least alkali of all
The most concentrated acid needed the least alkali
26.
Eight groups used the same method. Which is the most likely cause of Group E's result?
Dr Dabour Hub Academy - figure 4
They stopped adding alkali before the indicator reached green
They kept adding alkali after the indicator had turned green
They measured out only 20 cm³ of acid instead of 25 cm³
They used a more concentrated alkali than the other groups
27.
A toothpaste advert says: "Neutralises 50% more acid!" What extra information is most needed to judge this claim?
What it was compared with, and how the acid neutralised was measured
The colour and flavour of the toothpaste that was tested
The name of the scientist who did the tests in the laboratory
How many people in the advert said they liked the toothpaste
28.
Why does Musa put a white tile under the flask while he adds alkali to acid containing indicator?
It keeps the flask cool so the reaction does not get too hot
It makes the colour change of the indicator easier to see
It absorbs any acid that splashes, so goggles are not needed
It stops the flask moving, so no stirring or swirling is needed
29.
Which statement best describes the pattern in these results?
pH falls by the same amount each time the lemon juice is doubled
pH falls sharply from 0 to 10%, then only slightly as more is added
pH halves every time the percentage of lemon juice is doubled
pH rises steadily because lemon juice makes the drink alkaline
30.
Which term is described as: a factor that can change?
fair test
pH
conclusion
variable
31.
Which term is described as: a scale used to describe acidity and alkalinity?
variable
fair test
conclusion
pH
32.
Which term is described as: a statement supported by results?
variable
fair test
pH
conclusion
33.
Which term is described as: an investigation changing one variable while controlling others?
variable
conclusion
fair test
pH
34.
Match the term to its correct meaning: excess
the reaction of an acid with a base to give a salt and water
giving out energy, as neutralisation does
a substance that neutralises an acid, such as a metal oxide, hydroxide or carbonate
more of a reactant than is needed, added to make sure the reaction is complete
35.
Anjali neutralised 10 cm³ of five vinegars of known concentration, then tested a vinegar with no label, which needed 28.0 cm³ of alkali. Using the line of best fit, the unlabelled vinegar contains _____ acid.
Dr Dabour Hub Academy - figure 5
about 5 %
about 8 %
about 7 %
about 14 %
36.
The diagram shows close-ups of Sofia's burette at the start and at the end of adding alkali to some acid. The volume of alkali she added was _____.
Dr Dabour Hub Academy - figure 6
22.2 cm³
25.2 cm³
23.7 cm³
21.2 cm³
37.
Results that are close to the true value are described as _____.
repeatable results
accurate results
anomalous results
categorical results
38.
A result that does not fit the pattern of the other results is called _____.
a control variable
a mean result
a prediction
an anomalous result
39.
When comparing antacid brands, diluting the acid for some tests but not others changes a control variable and makes the test unfair. True or false?
False – the statement is wrong
True – the statement is correct
False – acid strength does not affect how much antacid is needed
False – diluting the acid is the independent variable here
40.
Read the graph. By day 3, the pH of the milk at 25 °C had fallen by 1.7 units, while the milk in the fridge had fallen by only 0.1 units. True or false?
Dr Dabour Hub Academy - figure 7
True – the statement is correct
False – the statement is wrong
False – the fridge milk fell by more than the milk at 25 °C
False – the milk at 25 °C had fallen by 5.0 units by day 3
41.
The variable you deliberately change in an investigation is the independent variable. True or false?
True – the statement is correct
False – the statement is wrong
False – that is called the dependent variable
False – that is called the control variable
42.
Burette readings are to 0.1 cm³, so a mean of 18.466 cm³ should be recorded as 18.5 cm³. True or false?
False – the statement is wrong
False – all three decimal places must be kept
False – it should be rounded to 18 cm³
True – the statement is correct
43.
Setting up a tube of acid with no antacid added lets you check that any pH change is caused by the antacid. True or false?
True – the statement is correct
False – the statement is wrong
False – a tube without antacid is pointless, as nothing happens
False – it would make the test unfair, as it has a different volume
44.
Ivan tested acid volumes from 10 to 50 cm³. He can be certain from his graph how much alkali 200 cm³ of the acid would need. True or false?
False – he cannot be sure outside the range tested
True – the statement is correct
True, because a line can always be extended
True, but only if he used a burette
45.
Three repeat results that are very close together show the results are repeatable, but they could still all be inaccurate. True or false?
False – the statement is wrong
False – close repeats always mean the results are accurate
True – the statement is correct
False – close repeats mean the equipment must be faulty
46.
A 100 cm³ measuring cylinder marked every 1 cm³ measures a volume of alkali as precisely as a burette marked every 0.1 cm³. True or false?
True – the statement is correct
False – the burette's smaller divisions make it more precise
True, because both are made of glass
True, but only for volumes under 10 cm³
47.
Wearing goggles removes the hazard of sodium hydroxide solution. True or false?
True – the statement is correct
True, because goggles neutralise any alkali that splashes
False – it reduces the risk, but the hazard is still there
True, but only if gloves are also worn
48.
If two variables change together in an investigation, this proves that one causes the change in the other. True or false?
True – the statement is correct
False – a third factor could affect both
True, as long as the results were repeated
True, but only when the graph is a straight line
49.
The end point of a titration is when the indicator changes colour. - True or false?
True
False
50.
A line of best fit should join every plotted point dot-to-dot. True or false?
True – the statement is correct
True, so that no result is left out of the graph
True, but only when there are fewer than five points
False – it follows the overall trend of the points
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Part of Unit 8: Rates of reaction — see every lesson and quiz in this unit.
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