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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

8.3 Simple Chemical Reactions

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Simple Chemical Reactions Checkpoint Chemistry quiz set 2: free practice for Cambridge Checkpoint (chemistry). Work through this Simple Chemical Reactions Checkpoint Chemistry quiz set 2 and get instant feedback on every answer. If you get stuck, review the 16.3 Simple chemical reactions 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.
Complete thermal decomposition of calcium carbonate leaves about 56% of the starting mass as calcium oxide. Which sample was most likely NOT heated for long enough?
Sample A – it lost the most mass of all
Sample B – it has the lowest final mass
Sample C – its loss is not a whole number
Sample D – it kept about 82% of its mass
2.
Which statement correctly describes product?
a starting substance in a reaction
an element usually showing typical metallic properties
a gas giving a squeaky pop with a lighted splint
a substance formed in a reaction
3.
Arjun concludes from his results that paraffin gives out the least heat when it burns. Why is this conclusion not valid?
Each fuel burned the same mass, 1.0 g
Paraffin gave the smallest temperature rise
Combustion of every fuel gives out the same heat
Paraffin heated twice the volume of water
4.
Burning magnesium in air can be called both combustion and oxidation. Why?
It gives out light, and loses oxygen
It makes a gas, and the metal is broken down by heat
It melts in the flame, and changes into an oxygen gas
It burns in oxygen, and the magnesium gains oxygen
5.
Which statement correctly describes hydrogen?
a starting substance in a reaction
a substance formed in a reaction
an element usually showing typical metallic properties
a gas giving a squeaky pop with a lighted splint
6.
Priya heats calcium carbonate strongly in the apparatus shown. At the end, her teacher says she must lift the delivery tube out of the limewater BEFORE turning off the Bunsen burner. What is the best reason?
Dr Dabour Hub Academy - figure 1
So that cold limewater is not sucked back into the hot tube
So that the calcium oxide made does not turn back into chalk
So that carbon dioxide can escape into the room more quickly
So that the limewater stays clear and gives a fair result
7.
Hana added alkali from a burette to acid containing universal indicator until the flask looked as shown. The diagram also shows her burette readings. Which conclusion is correct?
Dr Dabour Hub Academy - figure 2
She overshot: less than 23.5 cm³ was needed to neutralise the acid
Exactly 23.5 cm³ of alkali was needed to make the acid neutral
The acid is still in excess, so she should add more alkali slowly
The purple colour shows that no chemical reaction took place
8.
Tariq heats magnesium ribbon in a crucible using the apparatus shown. Every minute he uses tongs to lift the lid slightly for a moment and then puts it back. Why does he do this?
Dr Dabour Hub Academy - figure 3
To let hydrogen gas escape so the crucible does not crack
To let in fresh air, while keeping the white oxide smoke inside
To let the magnesium cool down so that it does not melt
To let carbon dioxide out, as this gas stops the reaction
9.
Zainab added sodium hydroxide solution, 4 cm³ at a time, to 25 cm³ of hydrochloric acid in an insulated cup and recorded the highest temperature after each addition. What volume of alkali exactly neutralised the acid?
Dr Dabour Hub Academy - figure 4
25 cm³, the same volume as the acid used
40 cm³, when the last portion of alkali was added
About 20 cm³, where the temperature peaks
About 4 cm³, as the temperature rose straight away
10.
Each option pairs a reaction with its products. Which pairing is correct?
Burning methane – carbon monoxide and hydrogen gas
Zinc with hydrochloric acid – zinc oxide and water
Heating calcium carbonate – calcium oxide and carbon dioxide
Rusting of iron – iron chloride and hydrogen gas
11.
Which statement correctly describes metal?
a starting substance in a reaction
a substance formed in a reaction
a gas giving a squeaky pop with a lighted splint
an element usually showing typical metallic properties
12.
Which practical work belongs to Simple Chemical Reactions?
Relate neutralisation to antacids, soil treatment and industrial waste treatment
Use observations, precipitates, temperature change and gas tests as evidence of reaction
Plan and evaluate a fair test comparing acids, alkalis or neutralisation reactions
Compare metal reactions and use the hydrogen “pop” test safely under supervision
13.
The "Before" box shows one methane molecule and two oxygen molecules. Four students each drew the particles after complete combustion. Which drawing is correct?
Dr Dabour Hub Academy - figure 5
After B – fewer molecules, as the gas is used up
After C – the molecules just split into atoms
After D – extra oxygen is made during burning
After A – every atom is kept, now in new molecules
14.
A 5.0 g iron nail rusts completely. How does the mass of the rust compare with 5.0 g?
More, because oxygen and water combined with the iron
Less, because the iron is eaten away as the rust forms
The same, because mass is conserved in every reaction
Less, because rust is a light, flaky and crumbly solid
15.
Which of these is the FIRST step in the correct order?
observe evidence of reaction
test the gas
identify the products
place the reactants together
16.
Omar put an open beaker containing 50.00 g of dilute acid on a balance and added 2.00 g of zinc. When the fizzing stopped, the reading was 51.94 g. What mass of hydrogen escaped?
1.94 g of hydrogen escaped
0.06 g of hydrogen escaped
2.00 g, the mass of all the zinc
None – mass is always conserved
17.
Which statement correctly describes closed system?
the loss of oxygen by a substance
a container from which nothing can escape, used to show conservation of mass
the reaction of a substance with oxygen giving out energy
the breaking down of a compound by heating
18.
Car makers paint steel car bodies. How does an unbroken coat of paint stop the steel from rusting?
It reacts with the rust and changes it back into iron
It makes the iron heavier, so oxygen cannot join
It keeps both oxygen and water away from the iron
It turns the iron into a metal that is not able to rust
19.
Iron + sulfur when heated form:
Iron oxide
Iron sulfide
Sulfur dioxide
Iron chloride
20.
Ahmed trapped 100 cm³ of air in a tube with damp iron wool, standing in water. Which conclusion do his results best support?
Rusting used all the air, as water rose every day
Rusting made a gas, so the gas volume in the tube changed
Rusting used about one fifth of the air, then it stopped
Rusting used 79 cm³ of air during the seven days
21.
Tariq investigates how the mass of magnesium used affects the mass of magnesium oxide made. Each option pairs a variable type with a variable. Which pairing is correct?
Dependent – mass of magnesium oxide formed
Independent – mass of magnesium oxide formed
Control – mass of magnesium ribbon used
Dependent – the type of crucible and lid
22.
Each option pairs a scientific claim with evidence offered for it. Which pairing is correct?
A new substance forms – the mixture was stirred with a glass rod
Mass is conserved – a sealed flask weighs the same after reacting
Oxygen was gained – the product was a powder of a different size
A gas was made – the reaction happened quickly in an open beaker
23.
When zinc carbonate is heated, it turns from white to yellow and a gas is given off that turns limewater milky. On cooling, a white solid (zinc oxide) remains. Which word equation fits these observations?
zinc carbonate → zinc oxide + carbon dioxide
zinc carbonate + oxygen → zinc oxide + carbon dioxide
zinc + carbon dioxide → zinc carbonate
zinc carbonate → zinc + oxygen + carbon dioxide
24.
Deepa tested how much lime (calcium hydroxide) neutralises a sample of acidic garden soil. Her farmer uncle says: "Add five spoonfuls per sample to be safe." Using the graph, which is the best reply?
Dr Dabour Hub Academy - figure 6
Sensible, as extra lime cannot change the pH once it is 7
Too much – 5 give pH 10.2 (alkaline); 3 spoonfuls give pH 7
Not enough, since the soil is still acidic after 5 spoonfuls
Sensible, as more lime always makes plants grow better
25.
Which statement correctly describes balanced equation?
the loss of oxygen by a substance
a container from which nothing can escape, used to show conservation of mass
the principle that the total mass of the products equals the total mass of the reactants
an equation with the same number of each kind of atom on both sides
26.
Each option pairs a substance with its role in a named reaction. Which pairing is correct?
Hydrogen in zinc + acid – a reactant
Water in neutralising – a reactant
Calcium oxide in making lime – a reactant
Oxygen in rusting iron – a reactant
27.
Kofi reacted 0.2 g of zinc granules with excess dilute hydrochloric acid and collected the gas in a 100 cm³ gas syringe. Why does the line on his graph become flat after about 4.5 minutes?
Dr Dabour Hub Academy - figure 7
All the zinc has reacted, so no more gas is produced
The gas syringe is full and cannot collect any more
The acid has all been used, although zinc is left over
The hydrogen has begun to turn back into solid zinc
28.
Mei compared three antacid powders. Which conclusion is justified by her results?
Z – its results are the most repeatable
X – it lies between the other two brands
Y – a spoonful of it neutralises the most acid
Y is the weakest, as it needed fewest spoonfuls
29.
Leila did four reactions in open containers. She concludes: "Mass is not conserved in three of these reactions." Which is the best response?
Right – only neutralisation obeys conservation of mass
Right – mass is made when burning and lost when heating
Wrong – gases entered or escaped from the open containers
Wrong – the balance must be faulty, as mass never changes
30.
Which step comes immediately after "observe evidence of reaction"?
place the reactants together
identify the products
test the gas
31.
Which term is described as: a starting substance in a reaction?
product
metal
hydrogen
reactant
32.
Which term is described as: a gas giving a squeaky pop with a lighted splint?
reactant
product
metal
hydrogen
33.
Which term is described as: a substance formed in a reaction?
reactant
hydrogen
product
metal
34.
When 0.60 g of magnesium burned to make 1.00 g of magnesium oxide, the mass of oxygen that combined with it was _____.
0.40 grams
1.60 grams
0.60 grams
1.00 grams
35.
Conservation of mass means the total mass of the products equals the total mass of the _____.
solid products
gases given off
container used
reactants used
36.
Neutralising hydrochloric acid with sodium hydroxide solution makes sodium chloride and _____.
hydrogen gas
water (H₂O)
carbon dioxide
oxygen gas
37.
When calcium carbonate is heated strongly, it breaks down into calcium oxide and _____.
oxygen gas only
hydrogen gas
carbon dioxide gas
calcium metal
38.
The loss of oxygen is called _____.
oxidation
corrosion
combustion
reduction
39.
Zinc reacting with hydrochloric acid is a neutralisation, because a salt is made. True or false?
True – every reaction making a salt is neutralisation
False – there is no alkali, and hydrogen gas forms
True – zinc is an alkali, so water forms
False – no salt forms, only hydrogen gas is made
40.
In a thermal decomposition, a single reactant breaks down into two or more products when it is heated. True or false?
False – it needs two reactants to react
False – the substance only melts and does not change
True – one substance splits into simpler ones
True, but only if oxygen from the air joins as well
41.
Swallowing an antacid containing magnesium hydroxide raises the pH of the stomach contents towards 7. True or false?
True – it neutralises some stomach acid
False – the pH drops further below 1
False – antacids add more acid instead
True, as it turns the stomach alkaline
42.
Burning petrol and rusting iron are both oxidation reactions, but only burning is fast and gives a flame. True or false?
False – rusting does not involve any oxygen
False – burning petrol is a decomposition
True – both gain oxygen, but rusting is slow
True, but rusting is a reversible reaction
43.
Statement: Group 3 probably lost some white smoke or stopped heating too early, because the other groups all made 5 g of oxide for every 3 g of magnesium. True or false?
False – group 3 gained the most oxygen of all
True – 0.30 g should have given 0.50 g of oxide
False – group 4 is the anomaly, it has the largest mass
False – all four ratios in the table are the same
44.
When an iron gate rusts, the iron is oxidised. True or false?
False – rusting is a thermal decomposition
True – iron gains oxygen, forming iron oxide
False – rust forms from water alone, no oxygen
True – the iron loses oxygen to the damp air
45.
In a word equation, the reactants are written to the left of the arrow and the products to the right. True or false?
False – products always come first
False – both are listed on each side
True, but only for burning reactions
True – it reads reactants → products
46.
Statement: after burning, the white powder has less mass than the magnesium ribbon because some magnesium turned into light. True or false?
True – light and heat carry some of the mass away
True – some of the magnesium atoms are destroyed
False – oxygen atoms join, so its mass increases
False – the mass stays exactly the same
47.
During neutralisation of an acid with an alkali, universal indicator turns green when the mixture is neutral. True or false?
False – it turns red at pH 7
True – green shows that pH is 7
False – it turns purple when neutral
True, but only if the acid is weak
48.
Heating calcium carbonate is an oxidation, because the calcium oxide made contains oxygen. True or false?
True – any product that contains oxygen is oxidised
True – the calcium joins with oxygen from the air
False – it is a neutralisation, as lime is an alkali
False – no oxygen is gained; it is decomposition
49.
Rahul says: "Neutralisation is only a physical change, because the solution just goes from acidic to neutral." True or false?
False – salt and water are both new substances
True – nothing new forms when solutions mix
True – pH changes are always physical changes
False – because it gives off hydrogen gas too
50.
Statement: to get accurate results, a crucible of magnesium oxide should be weighed while still hot, straight after heating. True or false?
True – hot gives the true mass
True – cooling would let the oxide escape
False – it should be weighed during heating
False – let it cool first, then weigh
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Part of Unit 8: Rates of reaction — see every lesson and quiz in this unit.
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