CIE iGCSE Co-Ordinated Science C9.1 Properties of metals Exam Style Questions Paper 3
Question
(a) Copper is a metal in high demand that is now often recycled.
To recycle copper, it must be melted down into a liquid.
(i) Suggest one reason other than cost why copper and other metals are recycled.
(ii) Describe two differences between the arrangement and motion of atoms in molten
copper and the arrangement and motion of atoms in solid copper.
(b) A metal coin is covered with a layer of copper by electroplating.
(i) The coin is used as one of the electrodes.
State for which electrode the coin is used.
(ii) Suggest a suitable solution to be used as the electrolyte for electroplating the coin.
(iii) Electroplating uses the process of electrolysis; a definition is provided.
Electrolysis is the breakdown of a covalent compound when solid or in aqueous solution by the passage of electricity.
This definition of electrolysis is not correct.
Circle the two words in the definition that are not correct.
▶️Answer/Explanation
Ans : 8(a)(i) copper (ore) is a finite resource ;
8(a)(ii) arrangement – solid regular and liquid irregular ;
motion – solid vibrate (about fixed point) only / do not move AND liquid are able to move about ;
8(b)(i) cathode ;
8(b)(ii) copper sulfate / copper chloride ;
8(b)(iii) covalent ;
solid ;
Question
(a) Table 5.1 shows the observations for the reactions of four metals with water
(i) Place the four metals in order of reactivity from the most reactive to the least reactive.
(ii) Name one metal from Table 5.1 that is found in Group I of the Periodic Table.
…………………………………………………………………………………………………………………….
(iii) Name one metal from Table 5.1 that is a transition element.
…………………………………………………………………………………………………………………….
(b) Copper is extracted from its ore. Copper(II) oxide is made and then copper.
(i) The extraction of copper involves an endothermic reaction.
State what is meant by an endothermic reaction.
………………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
(ii) Explain why copper(II) oxide is described as a basic oxide.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
…………………………………………………………………………………………………………………….
(c) Copper is also extracted from its ore by electrolysis.
Define electrolysis by completing the sentence.
Electrolysis is the breakdown of an ionic compound when ……………………………
or in aqueous solution by the passage of …………………………… .
(d) Brass is an alloy of copper and zinc.
(i) Apart from cost, suggest why brass is used to make keys but pure copper is not used to
make keys.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
(ii) Copper has a melting point of 1084 °C.
Zinc has a melting point of 420 °C.
The brass alloy has a range of melting points from 905 °C to 932 °C.
Explain why brass does not have a single melting point.
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
………………………………………………………………………………………………………………………….
▶️Answer/Explanation
Ans : 5(a)(i) potassium
lithium
calcium
copper
potassium and copper correct ;
lithium and calcium correct ;
5(a)(ii) lithium / potassium ;
5(a)(iii) copper ;
5(b)(i) temperature decreases / thermal energy is absorbed (from the surroundings) ;
5(b)(ii) is a metal oxide ;
5(c) molten / liquid ;
electricity ;
5(d)(i) brass is more hardwearing / stronger ;
5(d)(ii) brass is a mixture ;
Question
(a) A list of metals is shown
aluminium
copper
iron
lead
magnesium
platinum
sodium
Identify from the list the metal that is:
(i) found in Group I of the Periodic Table.
…………………………………………………………………………………………………………………….
(ii) extracted from the ore bauxite.
…………………………………………………………………………………………………………………….
(iii) the main metal in the alloy steel.
…………………………………………………………………………………………………………………….
(iv) used as inert electrodes in electrolysis.……………………………………………………………………………………………………………………. [1]
(b) Table 2.1 gives some information about the rate of reaction of four metals with cold water and with dilute hydrochloric acid.
(i) Deduce the order of reactivity of the four metals from the most reactive to the least reactive.
(ii) Only magnesium in Table 2.1 reacts with cold water.
Suggest one other metal, not from Table 2.1, that reacts quickly with cold water.
(iii) In an experiment, magnesium reacts with dilute hydrochloric acid as shown in Fig. 2.1.
State two ways of changing the dilute hydrochloric acid to make the reaction faster.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
(iv) The word equation for the reaction between magnesium and dilute hydrochloric acid is shown.
magnesium + hydrochloric acid → magnesium chloride + hydrogen
Complete the balanced symbol equation for this reaction.
Mg + ……..HCl → MgCl$_{2}$ + H$_{2}$
▶️Answer/Explanation
Ans : 2(a)(i) sodium ;
2(a)(ii) aluminium ;
2(a)(iii) iron ;
2(a)(iv) platinum ;
2(b)(i) magnesium
zinc
iron
copper
magnesium and copper correct ;
zinc and iron correct ;
2(b)(ii) lithium, sodium, potassium etc. ;
2(b)(iii) increase concentration of acid ;
increase temperature of acid ;
2(b)(iv)2 HCl ;
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) The list gives the names of six compounds.
aluminium oxide
ammonium nitrate
carbon dioxide
lead bromide
sodium chloride
sulfur dioxide
Answer the questions about these compounds.
Each compound may be used once, more than once or not at all.
State which compound:
(i) has the formula PbBr2.
(ii) is a salt from which ammonia can be displaced.
(iii) is an acidic oxide.
(iv) is a greenhouse gas.
(v) is the main constituent of bauxite.
(b) Aluminium, copper and iron are all solid metals.
State three general physical properties of solid metals.
1 …………………………………………………………………………
2 …………………………………………………………………………
3 …………………………………………………………………………
(c) (i) Duralumin is an alloy of aluminium.
Table 2.1 shows the percentage composition of duralumin.
Calculate the mass of aluminium in 20 kg of duralumin.
mass of aluminium = ……………………………………………. kg
(ii) Table 2.2 shows the melting points of aluminium, copper, magnesium and duralumin.
Duralumin does not have a precise melting point but melts over a range of temperatures.
Explain why duralumin does not have a precise melting point.
▶️Answer/Explanation
Ans : 2(a)(i) lead bromide ;
2(a)(ii) ammonium nitrate ;
2(a)(iii) carbon dioxide / sulfur dioxide ;
2(a)(iv) carbon dioxide ;
2(a)(v) aluminium oxide ;
2(b) any three from:
conducts heat ;
conducts electricity ;
malleable ;
high melting/boiling point ;
2(c)(i) 95 / 100 × 20 = 19 (kg) ;
2(c)(ii) because it is not a pure substance / it is a mixture ;
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
(a) Table 5.1 shows information about four metallic elements.
| Metal | Reaction of metal with water |
|---|---|
| Copper | Does not react with water |
| Iron | Reacts very slowly with water |
| Lithium | Reacts rapidly with water |
| Sodium | Reacts very rapidly with water |
(i) State the names of the two metals in Table 5.1 that are transition elements.
▶️Answer/Explanation
Copper and iron
(ii) Suggest the name of the gas produced when an alkali metal reacts with water.
▶️Answer/Explanation
Hydrogen
(iii) Place the four metals in order of reactivity from the most reactive to the least reactive.
▶️Answer/Explanation
Sodium, lithium, iron, copper
(b) Copper is extracted by heating copper oxide with carbon.
The word equation for the reaction is shown.
copper oxide + carbon → copper + carbon dioxide
(i) Balance the symbol equation for this reaction.
▶️Answer/Explanation
2CuO + C → 2Cu + CO2
(ii) Identify which substance is reduced during this reaction. Explain your answer.
▶️Answer/Explanation
Copper oxide is reduced because it loses oxygen.
(c) During the extraction of copper, carbon dioxide is released into the air.
Carbon dioxide is found in small quantities in clean air.
(i) State the names of the two gases which are found in large quantities in clean air.
▶️Answer/Explanation
Oxygen and nitrogen
(ii) Carbon dioxide is a greenhouse gas. State the name of one other greenhouse gas.
▶️Answer/Explanation
Methane
(iii) Carbon dioxide is released into the air during the combustion of fossil fuels. State the names of two fossil fuels.
▶️Answer/Explanation
Coal and petroleum
Question
(a) Potassium is a very reactive metal. Potassium is stored under oil as shown in Fig. 5.1.
Suggest two reasons why potassium is stored under oil.
▶️Answer/Explanation
1. To prevent potassium from reacting with air or oxygen.
2. To prevent potassium from reacting with water vapor.
(b) Potassium has a proton number of 19. Complete Fig. 5.2 to show the electronic structure of a potassium atom. The inner shell electrons have been drawn for you.
▶️Answer/Explanation
The electronic structure of a potassium atom is 2, 8, 8, 1.
(c) Solid potassium reacts with chlorine gas to make solid potassium chloride.
(i) Describe the differences between the structures of a solid and a gas in terms of particle separation and particle arrangement.
▶️Answer/Explanation
Particle separation: In a solid, particles are closely packed together, while in a gas, particles are far apart.
Particle arrangement: In a solid, particles are arranged in a regular pattern, while in a gas, particles are arranged randomly.
(ii) When potassium reacts with chlorine, potassium atoms become potassium ions. Describe what happens to a potassium atom when it becomes a potassium ion.
▶️Answer/Explanation
A potassium atom loses one electron to become a potassium ion (K⁺).
(iii) Potassium and chlorine are elements. Potassium chloride is a compound. Describe the difference between an element and a compound.
▶️Answer/Explanation
An element is a substance made up of only one type of atom, while a compound is a substance made up of two or more different types of atoms chemically combined.
(d) The maximum mass of potassium chloride that dissolves in 100 cm³ of water is called the solubility of potassium chloride. Fig. 5.3 shows the solubility of potassium chloride in water at different temperatures.
(i) Describe the trend in solubility shown in Fig. 5.3.
▶️Answer/Explanation
The solubility of potassium chloride increases as the temperature increases.
(ii) State the mass of potassium chloride that dissolves in 100 cm³ of water at 45 °C.
▶️Answer/Explanation
41 g (±1)
Question
Calcium and copper are metals.
(a)(i) State two physical properties of metals.
▶️Answer/Explanation
1. Good electrical conductor
2. Good thermal conductor
(ii) Copper is a transition metal. Calcium is not a transition metal. State two properties of transition metals that are not properties of calcium.
▶️Answer/Explanation
1. Forms coloured compounds
2. Can act as a catalyst
(iii) Calcium and copper are added to separate amounts of water. Describe the reaction, if any, for each metal.
▶️Answer/Explanation
Calcium: Gas evolved, metal dissolves, white insoluble solid forms.
Copper: No change.
(b) Copper metal is produced when copper(II) oxide reacts with hydrogen gas. The equation for this reaction is shown.
CuO + H₂ → Cu + H₂O
(i) Explain why this equation is described as balanced.
▶️Answer/Explanation
The equation is balanced because the number of atoms of each element is the same on both sides of the equation.
(ii) Identify which substance is reduced in this reaction. Explain your answer.
▶️Answer/Explanation
Substance: CuO
Explanation: CuO loses oxygen, which is a reduction reaction.
(c) Metals are covered with a thin layer of copper during electroplating. Fig. 8.1 shows apparatus and materials to electroplate a metal key with copper.
Draw a diagram to show the apparatus and materials set up to electroplate the metal key with copper.
▶️Answer/Explanation
Key and copper electrode connected and dipping into the solution; correct polarity.