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Question 1
Many metals are extracted by removing oxygen from their ores. Use the reactivity series to help you answer this question. |
a) | Aluminium cannot be produced by reacting aluminium oxide with carbon. Why does aluminium oxide not react with carbon? A aluminium is less reactive than carbon B carbon is less reactive than aluminium C oxygen is more reactive than carbon
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b) | State how oxygen can be removed from zinc oxide to make zinc.
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c) | What name is given to a reaction in which oxygen is removed from a substance?
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Question 2
Iron and zinc can be obtained by heating iron and zinc oxides with carbon in a blast furnace, but electrolysis has to be carried out to obtain aluminium from its oxide. The image below shows part of the reactivity series. |
a) | Draw an arrow on the reactivity series above to show where carbon fits into the series.
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b) | The formula for zinc oxide is ZnO. Write a balanced equation for the extraction of zinc in the blast furnace.
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c) | Predict the method of extraction used to obtain calcium from its ore and explain your answer.
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d) | A student wants to compare the reactivity of an unknown metal, M, with that of zinc. Both metals are more reactive than silver. The student is provided with:
No other chemicals are available. Describe a method the student could use to compare the reactivity of metal M with that of zinc. Your method should give valid results.
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Question 3
Tungsten (W) is a metal. Tungsten can be extracted from tungsten oxide (WO3) using three different methods. The table below shows information about the three different methods of extraction of tungsten. In order to use the tungsten after its extraction, any other solid products made must be separated from the tungsten. |
a) | Evaluate the three methods for extracting tungsten from tungsten oxide.
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b) | The equation for the extraction of tungsten from tungsten oxide using hydrogen is: WO3 + 3 H2 ➔ W + 3 H2O Calculate the percentage atom economy when tungsten is produced in this reaction.
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Question 4
A student reacted two different metals, magnesium and copper, with oxygen in the air. The image below shows magnesium burning in air.
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a) | Give one observation that indicates that a chemical reaction is taking place.
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b) | Give the balanced symbol equation for the reaction, and name the product of the reaction.
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c) | The magnesium needed heating before it would react. Which of the following statements is a conclusion that can be drawn from this? A the reaction is exothermic B the reaction is reversible C magnesium has a high melting point D the reaction has a high activation energy
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d) | A sample of the product was added to water and shaken. Universal indicator was added. The universal indicator turned blue. |
d) i) | Give the name of the substance made when the product reacted with water.
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d) ii) | What kind of substance is this? A neutral B alkali C acid
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e) | When heated in the presence of oxygen, copper doesn't burn, but its surface is converted to black copper oxide. Compare the reactivity of magnesium with that of copper.
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Question 5
Haematite is an ore of iron. Haematite contains iron oxide, Fe2O3. Iron is extracted from iron oxide in a blast furnace. |
a) | What is the meaning of the term 'ore'?
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b) | What type of chemical reaction produces the iron in the blast furnace?
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c) | In the blast furnace, iron oxide reacts with carbon to produce iron and carbon dioxide. Write a balanced symbol equation for this reaction.
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d) | Pure iron is relatively soft and not very strong. The iron from the blast furnace is very hard and brittle. It contains about 4% carbon and is used as cast iron. Explain the differences in the properties of pure iron and cast iron.
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Question 6
Copper is a widely used metal. The main ore of copper contains copper sulfide. Copper can be extracted from copper sulfide in a three stage process. |
a) | Balance the symbol equation representing the first stage of copper extraction. Cu2S + O2 ➔ CuO + SO2 2 2
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b) | Explain the environmental problem that would result from the escape of the gas product from this reaction into the atmosphere.
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c) | In the second stage, copper oxide, CuO, is reduced using carbon. Describe and explain what happens during this reaction.
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d) | During the third stage, the copper is purified using electricity. Name this process.
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e) | Where copper ore has been mined there are areas of land that contain very low percentages of copper compounds. One way to extract the copper is to grow plants on the land. The plants absorb copper compounds through their roots, and then are burned to produce copper oxide. The copper oxide produced from plants can be reacted to produce copper or copper sulfate solution. |
What is the name of the process described above?
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f) | Some people believe that recycling copper may be better than extracting copper from its ores. Explain the advantages and disadvantages of recycling copper instead of extracting it from its ores.
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Question 7
Metals are useful materials. The table below shows information about some metals. |
a) | Use information in the table to suggest why gold and platinum are very expensive metals.
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b) | Gold and platinum are very unreactive. For this reason, gold and platinum exist as pure metals and do not need to be extracted from ores. What is the name given to metals that do not need to be extracted from ores? A native metals B foreign metals C simple metals D complex metals
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c) | Aluminium and iron are made by reduction of their ores. Name the element that is removed from the ores when they are reduced.
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d) | Iron is produced from haematite in a blast furnace. Haematite is an ore of iron which contains mainly iron oxide (Fe2O3). How is iron oxide reduced in a blast furnace to make iron?
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e) | A chemical reaction for the extraction of iron is: Fe2O3 + 3CO ➔ 2Fe + 3CO2
Complete the word equation for this chemical reaction.
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f) | Aluminium cannot be made in a blast furnace. Suggest one reason why aluminium is more expensive than iron.
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g) | Suggest why the annual world production of iron is forty times greater than that of aluminium.
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Question 8
This question is about the reactions of metals and acids. A student added four metals to a dilute acid. |
a) | Name:
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b) | Zinc reacted with the acid to produce zinc chloride and water. Give the name of the acid used by the student in his investigation.
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The student carried out another investigation.
This is the method she used.
The table below shows the student’s results. |
c) | Do the students results in the second experiment agree with her previous results? Explain your answer.
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d) | Calculate the mean temperature increase X for magnesium. Do not include the anomalous result in your calculation.
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e) | What type of variable is the volume of hydrochloric acid in this investigation? A control B dependent C independent
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f) | Suggest one way of improving the method to give results which are more repeatable.
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g) | The student used a polystyrene cup and not a glass beaker. Why did this make the investigation more accurate?
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Question 9
A student investigates the reactivity of metals. |
A student added copper metal to colourless silver nitrate solution. The student observed:
Explain how these observations show that silver is less reactive than copper.
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b) | A student is given three metals, X, Y and Z to identify. The metals are magnesium, iron and copper. Plan an investigation to identify the three metals by comparing their reactions with dilute hydrochloric acid. Your plan should give valid results.
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Question 10
This question is about halogens and their displacement reactions. The table below shows the colour of different elements in aqueous solution. |
A redox reaction takes place when aqueous chlorine is added to potassium iodide solution. The equation for this reaction is: Cl2 (aq) + 2KI (aq) ➔ I2 (aq) + 2KCl (aq) |
a) | What is the colour of the final solution in this reaction?
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b) | Give the ionic equation for the reaction of chlorine with potassium iodide.
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c) | Explain why the reaction between chlorine atoms and iodide ions is both oxidation and reduction.
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d) | All displacement reactions are examples of redox reactions. State the meaning of the term redox.
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Question 11
A student investigated the temperature change in displacement reactions between metals and copper sulfate solution. The table below shows the student’s results. |
a) | Plot the data from the table above as a bar chart.
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b) | The temperature change depends on the reactivity of the metal. Use the student’s results to place copper, iron, magnesium, tin and zinc in order of their reactivity, from most reactive to least reactive.
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c) | Write the balanced symbol equation for the reaction between iron and copper sulfate.
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d) | Write the ionic equation for the reaction between magnesium and copper sulfate.
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e) | Why is copper described as being reduced in these reactions?
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f) | The student repeated the experiment using aluminium. Aluminum does not react with the solution of copper sulfate. Suggest why.
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g) | Describe a method to find the position of an unknown metal in this reactivity series using a dilute acid. Your method should give valid results.
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