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GCSE Chemistry

GCSE Chemistry Flash Card Questions

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C5 Chemical changes

C5.1 The reactivity series

Question	Answer
List some items made using transition metals.	bicycles, cars, ships, trains, and aeroplanes
What is the raw material of metals called?	ore
What are ores?	ores are rocks from which it is economical to extract the metals they contain
What form are most metals in in ores?	in compounds bonded to other elements frequently oxides like iron (III) oxide
Write the word equation for the formation of iron (III) oxide.	iron + oxygen → iron (III) oxide
Write the symbol equation for the formation of iron (III) oxide.	4Fe (s) + 3O2(g) → 2Fe2O3(s)
Name the process when iron reacts with oxygen to become iron (III) oxide.	oxidation
Name the process when iron is extracted from iron (III) oxide.	reduction
What is the reactivity series of metals?	a list of metals in order of reactivity with the most reactive at the top and the least reactive at the bottom
Write the reaction of a group I metal with water.	metal + water → metal hydroxide + hydrogen gas
Write the reaction of a group I metal with dilute acid.	metal + acid → salt + hydrogen gas
Will sodium or magnesium react more strongly with water?	sodium as it is higher on the reactivity series
How do group I metals react with water?	they fizz reacting vigorously
How do group I metals react with dilute acid?	they explode
How does copper react with water?	it does not react at all which is why copper pipes are used to make water pipes
Will aluminium or tin react more strongly with dilute acid?	aluminium is higher in the reactivity series so has a stronger reaction with dilute acid than tin
How do silver and gold react with dilute acid?	they do not react at all

C5 Chemical changes

C5.2 Displacement reactions

Question	Answer
What happens to the metals in a displacement reaction?	the metal that starts off as atoms becomes positive ions, and the metal that starts off as positive ions becomes atoms
What is a displacement reaction?	a more reactive metal will displace a less reactive metal from an aqueous solution of one of its salts
Complete the reaction magnesium + copper (II) sulphate →	magnesium + copper (II) sulphate → magnesium sulphate + copper
Write the symbol version of the magnesium + copper (II) sulphate reaction with state symbols.	Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s)
What type of reaction is magnesium + copper (II) sulphate?	a displacement reaction
How do we know that magnesium + copper (II) sulphate is a displacement reaction?	by looking at the results which show that magnesium has taken the place of copper in the sulphate salt
What has happened to the magnesium in the magnesium + copper (II) sulphate reaction?	magnesium has become a 2+ ion of magnesium Mg2+
What has happened to the copper ion in the magnesium + copper (II) sulphate reaction?	the copper 2+ ion Cu2+ has become a neutral copper atom
Why does magnesium displace copper in the magnesium + copper (II) sulphate reaction?	because magnesium is more reactive than copper
What is an ionic equation?	it shows only the atoms and ions that change in a reaction
Write the ionic equation for Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s).	Mg(s) + Cu2+(aq) → Mg2+(aq) + Cu(s)
Why is the sulphate ion not included in the ionic equation for Mg(s) + CuSO4(aq) → MgSO4(aq) + Cu(s).	because it does not change but is SO42- on both sides of the reaction.
Which is more reactive out of zinc and lead?	zinc is more reactive than lead - it is higher up the reactivity series
Complete the symbol equation Zn(s) + Pb(NO3)2(aq).	Zn(s) + Pb(NO3)2(aq) → Pb(s) + Zn(NO3)2(aq).
Write the ionic equation for Zn(s) + Pb(NO3)2(aq).	Zn(s) + Pb2+(aq) → Zn2+(aq) + Pb(s)
Why is the nitrate ion not included in the ionic equation for Zn(s) + Pb(NO3)2(aq) → Pb(s) + Zn(NO3)2(aq).	because it does not change but is NO3- on both sides of the reaction.
How will the lead metal appear in the Zn(s) + Pb2+(aq) reaction?	the lead metal forms as crystals on the zinc
Which non-metals are included in the reactivity series?	hydrogen and carbon
Where is hydrogen H1+ on the reactivity series?	between copper and lead
Can copper displace the hydrogen in an acid?	no because copper is less reactive than hydrogen
Can lead displace the hydrogen in an acid?	yes because lead is more reactive than hydrogen
How is carbon displacement used in practise?	it is used to extract metals from their ores i.e. carbon displaces the metal from its oxide leaving the pure metal behind
Can carbon displace all metals from their oxides in their ores?	no, only the metals that are less reactive so below aluminium
Can carbon displace aluminium in aluminium oxide?	no, because carbon is less reactive than aluminium
Can carbon displace zinc from zinc oxide?	yes, because carbon is more reactive than zinc
Where is carbon on the reactivity series?	it is between aluminium and zinc
What is oxidation?	oxidation is the loss of electrons
What is reduction?	reduction is the gain of electrons
Do either oxidation or reduction take place in displacement reactions?	both oxidation and reduction occur in every displacement reaction
How is copper extracted from copper sulphate using displacement?	iron is used to displace the copper in copper sulphate
What iron is used to displace copper from copper sulphate?	cheap scrap iron
Write the symbol for the copper ion in copper sulphate.	Cu2+
Write the ionic equation for the displacement of iron from copper in copper sulphate.	Fe(s) + Cu2+(aq) → Fe2+(aq) + Cu(s)
Write the half equation for iron in the displacement of iron from copper in copper sulphate.	Fe(s) → Fe2+(aq) + 2e-
What has happened to the iron Fe in the previous half equation?	it lost 2 electrons thus it was oxidised
Write the half equation for copper in the displacement of iron from copper in copper sulphate.	Cu2+(aq) + 2e- → Cu(s)
What has happened to the copper Cu in the previous half equation?	it gained 2 electrons thus it was reduced
What is a redox reaction?	a reaction in which both reduction and oxidation take place
Why is a displacment reaction known as a redox reaction?	because both reduction and oxidation takes place

C5 Chemical changes

C5.3 Extracting metals

Question	Answer
Where are metals found?	in the earth's crust
What form do metals take in the earth's crust	most metals are combined with other elements, often oxygen or sulphur
What is a metal ore?	a rock containing enough of a metal or a metal compound to make it worth extracting the metal
What is the first step for ores like copper ore?	copper ore has to be concentrated before the copper can be removed
How is copper ore concentrated?	• the copper ore is ground to a fine powder • the copper ore is added to water • a chemical that makes the copper compound repel water is added • air is bubbled through the mixture • the copper compound floats and the rest sinks • the copper compound is scraped off the top, ready to be processed
What makes it worth extracting a metal from its ore?	• how easy it is to extract from its ore • how much metal the ore contains • the changing demands for a metal
Name some metals that exist in their native state.	gold and silver
Why are gold and silver found in their native state?	because they are so unreactive
What determines the way that a metal is extracted?	it position on the reactivity series in relation to carbon
What is the reactivity series?	a list of metals (plus carbon and hydrogen) in order of their reactivity
What methods are used to extract metals from their compounds?	• displacement using carbon • electrolysis
Why is carbon used to extract some of the metals from their ores?	because carbon is more reactive than the metails lower on the reactivity series
Name some metals found combined with oxygen as metal oxides.	aluminium, copper, lead, iron and zinc
Can carbon be used to extract aluminium from its oxide?	no, as aluminium is more reactive than carbon
Can carbon be used to extract iron from its oxide?	yes, as iron is less reactive than carbon
Describe the procedure for using carbon to extract a metal from its oxide.	• the metal oxide is heated with carbon • the carbon displaces the metal • carbon dioxide is formed • the metal remains as the metal on its own
Write the equation for using carbon to extract a metal from its oxide.	metal oxide + carbon → metal + carbon dioxide
Write the word equation for using carbon to extract lead from lead oxide.	lead oxide + carbon → lead + carbon dioxide
Write the symbol equation for using carbon to extract lead from lead oxide.	2PbO(s) + C(s) → 2Pb(l) + CO2(g)
What type of reaction is the removal of oxygen from lead oxide?	a reduction reaction
Write the formula for tungsten oxide?	WO3
Will carbon displace tungsten in tungsten oxide when heated together?	yes as carbon is more reactive than tungsten
Is carbon used to extract tungsten from tungsten oxide?	no, because it forms tungsten carbide with the metal displaced from tungsten oxide
What element is used to extract tungsten from tungsten oxide?	hydrogen
What is the quality of the tungsten produced using hydrogen to displace it from its oxide?	it is very pure
What is the name of the chemical process involved that removes tungsten from tungston oxide	reduction
Write the word equation for the reduction of tungsten oxide using hydrogen.	tungsten oxide + hydrogen → tungsten + water
Write the symbol equation for the reduction of tungsten oxide using hydrogen.	WO3 + 3H2 → W + 3H2O
How are metals more reactive than carbon extracted?	by electrolysis of the molten metal compound

C5 Chemical changes

C5.4 Salts from metals

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C5 Chemical changes

C5.5 Salts from insoluble bases

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C5 Chemical changes

C5.6 Making more salts

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C5 Chemical changes

C5.7 Neutralisation and the pH scale

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C5 Chemical changes

C5.8 Strong and weak acids

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