CIE iGCSE Co-Ordinated Science C8.4 Transition elements Exam Style Questions Paper 3
Question
(a) (i) An iron nail rusts when it is exposed to damp air.
Rusting involves the oxidation of iron.
State what is meant by the term oxidation.
(ii) Describe one method used to prevent the iron nail from rusting.
Explain how this method prevents the iron nail from rusting.
method …………………………………………………………………………
explanation …………………………………………………………………………
(b) Complete the sentence.
Metal ores are a finite resource and therefore, metals need to be ……………………………… .
(c) Iron is a transition element.
Put a tick (3) in the boxes next to all the correct statements about iron.
(d) Steel is an alloy of iron.
(i) Suggest why steel is used for making cars instead of pure iron.
(ii) Table 2.1 shows the percentage composition of stainless steel.
Calculate the mass of iron contained in 80 kg of stainless steel.
mass of iron = ……………………………………………. kg
(e) Iron is malleable.
State the meaning of malleable.
▶️Answer/Explanation
Ans : 2(a)(i) gain of oxygen ;
2(a)(ii) paint it ;
stops contact with air and water ; etc.
2(b) recycled ; OWTTE
2(c) iron acts as a catalyst ;
iron forms coloured compounds ;
2(d)(i) stronger ;
2(d)(ii) iron % 65 ;
80 × 65 / 100 = 52 (kg) ;
2(e) can be shaped or bent ;
Question
(a) State the name given to mixtures made from a metal with other elements.
(b) Iron is an element in Period 4 of the Periodic Table.
State the name of the collection of metals in Period 4 that contains iron.
(c) Describe the test used to identify iron(II) ions and give the observation for a positive result.
test ………………………………………………………………….
observation …………………………………………………….
(d) State the two substances that react with iron to make rust.
1 …………………………………………………………………………
2 ……………………………………………………………………….
(e) An isotope of iron has a proton number of 26 and a nucleon number of 58.
(i) Deduce the number of neutrons and the number of electrons in this isotope of iron.
neutrons = ………………………………………………………
electrons = ………………………………………………………
(ii) State the meaning of the term isotope.
(f) A teacher reacts dilute hydrochloric acid with four metals.
The observations are shown in Table 11.1.
Place the four metals in order of their reactivity from the most reactive to the least reactive.
most reactive ……………………………………………………………………..
least reactive ………………………………………………………………………
▶️Answer/Explanation
Ans : 11(a) alloy ;
11(b) transition elements / metals ;
11(c) aqueous sodium hydroxide ;
green precipitate ;
11(d) oxygen ;
water ;
11(e)(i) neutrons = 32 ;
electrons = 26 ;
11(e)(ii) atoms of the same element that have different numbers of neutrons ;
11(f) lithium calcium iron silver lithium and / or silver correct ;
all else correct ;
Question
(a) An isotope of magnesium has a proton number (atomic number) of 12 and a nucleon number (mass number) of 26.
Complete Table 5.1 to show the numbers of neutrons and electrons in an atom of this isotope.
(b) Fig. 5.1 shows part of the reactivity series of metals.
Magnesium reacts slowly with cold water.
Use the reactivity series to predict the result when calcium reacts with cold water.
Explain your answer.
prediction ………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………………………
explanation ……………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………………………
(c) Magnesium reacts with carbon dioxide. Magnesium oxide and carbon are made.
(i) Write the word equation for this reaction.
(ii) The reaction between magnesium and carbon dioxide is exothermic.
State what is meant by the term exothermic.
……………………………………………………………………………………………………………………
……………………………………………………………………………………………………………………
(d) Platinum is a transition metal. Magnesium is not a transition metal.
State two properties of platinum that are not properties of magnesium.
1 …………………………………………………………………………………………………………………..
2 ………………………………………………………………………………………………………………….
(e) Table 5.2 shows the composition of an alloy of magnesium.
Complete the table with the % by mass of magnesium.
Calculate the mass of magnesium in 1.0kg of the alloy.
mass = ……………………………………………. kg
▶️Answer/Explanation
Ans: 5(a)
5(b) calcium reacts quickly/quicker ;
calcium is higher in reactivity series than magnesium ;
5(c)(i) magnesium + carbon dioxide → magnesium oxide + carbon ;
5(c)(ii) releases (thermal) energy ;
5(d) any two from:
forms coloured compounds ;
acts as catalyst ;
variable valency ;
5(e) 91.5 (%) ;
0.915 (kg) ;
Question
(a) An atom of copper has a proton number of 29 and a nucleon number of 63.
(i) State the number of electrons in this copper atom. …………………………….
(ii) State the number of neutrons in this copper atom. …………………………….
(b) Copper oxide is heated with carbon. Copper and carbon dioxide are made.
(i) Write the word equation for this reaction.
(ii) In this reaction, reduction of copper in the copper oxide occurs.
Describe what is meant by the term reduction.
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
(iii) Explain why copper oxide is described as a basic oxide.
…………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
(c) Copper is a transition element.
Transition elements have high densities, high melting points and high boiling points. They are all metals.
State one other property of a transition element.
……………………………………………………………………………………………………………………..
……………………………………………………………………………………………………………………..
(d) (i) Brass is a mixture of copper and zinc.
State the term used to describe a mixture of metals.
…………………………………………………………………………………………………………………….
(ii) Brass is more malleable than either copper or zinc.
State the meaning of the term malleable.
…………………………………………………………………………………………………………………….
(iii) State the symbols of both copper and zinc.
copper symbol ……………………
zinc symbol ……………………
(e) A metal key is covered with a layer of copper by electroplating.
(i) The key is an electrode.
State which electrode is the key.
…………………………………………………………………………………………………………………….
(ii) Suggest a suitable electrolyte for electroplating the key.
…………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans: 8(a)(i) 29 ;
8(a)(ii) 34 ;
8(b)(i) copper oxide + carbon → copper + carbon dioxide ;
8(b)(ii) loss of oxygen ;
8(b)(iii) metal oxide / reacts with an acid to make a salt / neutralises an acid ;
8(c) any one from:
forms coloured compounds ;
acts as catalyst ; variable valency ;
8(d)(i) alloy ;
8(d)(ii) can be beaten into shape;
8(d)(iii) Cu and Zn ;
8(e)(i) cathode / negative ;
8(e)(ii) copper (II) sulfate ;
Question
Fig. 11.1 shows the apparatus and reagents used to make a salt.
(a) (i) State the name of process A shown in Fig. 11.1. (Sub-topic – C7.3)
▶️Answer/Explanation
filtration
Explanation: Process A is filtration, which is used to separate solid particles from a liquid.
(ii) State the name of the salt made in this experiment. (Sub-topic – C7.3)
▶️Answer/Explanation
copper sulfate
Explanation: The salt made in this experiment is copper sulfate.
(iii) Carbon dioxide gas is also made.
Explain why the bonds between the carbon atoms and the oxygen atoms in carbon dioxide are covalent. (Sub-topic – C2.5)
▶️Answer/Explanation
two non-metals bonding / electrons are shared
Explanation: The bonds between carbon and oxygen in carbon dioxide are covalent because they involve the sharing of electrons between the carbon and oxygen atoms. Carbon dioxide is a molecule formed by two non-metals (carbon and oxygen), and non-metals typically form covalent bonds by sharing electrons to achieve a stable electron configuration.
(iv) The temperature of the reacting mixture increases during the reaction.
State the name given to all chemical reactions that release heat. (Sub-topic – C5.1)
▶️Answer/Explanation
exothermic
Explanation: Chemical reactions that release heat are called exothermic reactions.
(v) The experiment is repeated using large pieces of copper carbonate instead of powdered copper carbonate.
State what happens to the rate of reaction. (Sub-topic – C6.2)
▶️Answer/Explanation
(rate of reaction) decreases
Explanation: Using large pieces of copper carbonate instead of powdered copper carbonate decreases the rate of reaction. This is because the surface area of the reactant is reduced, leading to fewer collisions between reactant particles per unit time.
(b) Copper carbonate is green. Copper is a transition metal.
State two other properties of transition metals which are not properties of all metals. (Sub-topic – C8.4)
▶️Answer/Explanation
1. high density; 2. catalyst; 3. variable valency (any two)
Explanation:
Two other properties of transition metals are:
- They form colored compounds.
- They can act as catalysts in chemical reactions.
(c) Brass is a mixture containing copper and zinc.
(i) State the name given to a mixture of metals. (Sub-topic – C9.3)
▶️Answer/Explanation
alloy
Explanation: A mixture of metals is called an alloy.
(ii) State one advantage of brass compared to copper. (Sub-topic – C9.3)
▶️Answer/Explanation
stronger / any valid point
Explanation: One advantage of brass compared to copper is that it is stronger and more resistant to corrosion.