C2 Patterns of Behaviour High

7/30/2019 C2 Patterns of Behaviour High

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Q1. The chart shows the processes involved in the manufacture of nitric acid from ammonia.

(a) Complete the word equation for the reaction that takes place in the first reaction vessel.

ammonia + .............................. nitrogen monoxide + water(1)

(b) (i) What is the use of the platinum gauze in the reaction vessel?

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(1)

(ii) At first, the platinum gauze is electrically heated. However, as the reaction continues,no further heating is necessary.Explain why.

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(c) Explain why the heat exchanger is used.

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(d) To convert nitrogen monoxide into nitric acid, two further reactants are needed.What are they?

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(e) In an old method, nitrogen monoxide was produced from nitrogen instead of ammonia.

The reaction was carried out at a high temperature (3000C).Suggest two reasons for this.

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(f) Complete the word equation below, to show how to make the fertiliser, ammonium nitrate.

................................... + .............................. ammonium nitrate + water(2)

(Total 10 marks)

Q2. (a) By reference to their structure, explain how the particles in a piece of metal are heldtogether and how the shape of the metal can be changed without it breaking.

(You may use a diagram in your answer.)

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(5)

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(b) Explain why metals are good conductors of electricity and suggest why this conductivityincreases across the periodic table from sodium to magnesium to aluminium.

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(Total 9 marks)

Q3. The following passage was taken from a chemistry textbook.

Germanium is a white, shiny, brittle element. It is used in the electronics industry because it isable to conduct a small amount of electricity.

It is made from germanium oxide obtained from flue dusts of zinc and lead smelters.The impure germanium oxide from the flue dusts is changed into germanium by the processoutlined below.

STEP 1 The germanium oxide is reacted with hydrochloric acid to make germanium tetrachloride. This is a volatile liquid in which the germanium and chlorine atoms are joined by covalent bonds.

STEP 2 The germanium tetrachloride is distilled off from the mixture.

STEP 3 The germanium tetrachloride is added to an excess of water to produce germanium oxide and hydrochloric acid.

STEPS 1 to 3 are repeated several times.

STEP 4 The pure germanium oxide is reduced by hydrogen to form germanium.

(a) Balance the equation below which represents the reaction in step 1.

GeO2

+ ............ HCl GeCl4 + ............ H

2O

(1)

(b) Write a word equation for the reaction in step 3.

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(c) Suggest why steps 1 to 3 are repeated several times.

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(d) The equation which represents the reaction in step 4 is shown below.

GeO2 + 2H

2 Ge + 2H

2O

(i) Explain what is meant by the term reduced.

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(ii) Calculate the mass of germanium which could be made from 525 g of germaniumoxide. (Relative atomic masses: Ge = 73; O = 16).

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Mass ......................................... g(3)

(e) Germanium is difficult to classify as either a metal or a non-metal.

(i) Give as much evidence as you can from the information in this question to supportthe view that germanium is a metal. Explain your answer as fully as you can.

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(ii) Give as much evidence as you can from the information in this question to supportthe view that germanium is a non-metal. Explain your answer as fully as you can.

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(Total 13 marks)

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Q4. (a) In an industrial process electricity is passed through a solution of sodium chloride inwater. A student set up the apparatus shown below to investigate this process.

(i) Name gas X.

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(ii) Complete the half equation for the production of chlorine gas during the electrolysis.

............ Cl ............ e Cl2

(1)

(iii) The student found that the solution left in the cell was alkaline.

Which ion makes the solution alkaline?

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(iv) Name the useful substance that can be obtained from the solution in the cell.

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(b) Sodium carbonate is another useful chemical that can be made from sodium chloride. Theflow chart below shows one way in which sodium carbonate can be made.

(i) Write the formula of sodium carbonate.Use the Data Sheet to help you to answer this question.

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(ii) Salt is one raw material used in this process.

Name one other raw material used in this process.

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(iii) Sodium carbonate is one of the products of this process.

Name one other product.

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(iv) 1. Give one example of a thermal decomposition reaction shown in the flowchart.

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2. Explain what is meant by a thermal decomposition reaction.

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(v) Name one substance that is recycled in this process.

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(c) When sodium carbonate solution is added to zinc sulphate solution a white solidisprecipitated.

(i) Use the Data Sheet to help you to name the white solid that is produced in thisreaction.

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(ii) State why this solid is formed.

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(Total 13 marks)

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Q5. (a) This label has been taken from a packet of Andrews Antacid.

(i) Write the simplest ionic equation which represents a neutralisation reaction.

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(ii) Chewing the tablet cures indigestion faster than swallowing the tablet whole. Explainwhy.

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(iii) Write the formula of the magnesium compound present inAndrews Antacid

.You may find the Data Sheet helpful.

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(b) The active ingredients in the Antacidreact with hydrochloric acid in the stomach to givesalts, water and carbon dioxide.

A student investigated how quickly the tablets react with excess hydrochloric acid.

40 cm of dilute hydrochloric acid were placed in a conical flask. The flask was placed ona direct reading balance. Two Antacidtablets were quickly added to the flask. The

apparatus was weighed immediately. At the same time, a stop clock was started. Themass was recorded every half minute for 5 minutes.

The results are shown in the table below.

The main active ingredient in Andrews Antacidis calcium carbonate.

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(i) Balance the equation which represents the reaction between calcium carbonate andhydrochloric acid.

CaCO3(s)

+ .......... HCl(aq)

CaCl2(aq)

+ H2O

(l)+ CO

2(g)

(1)

(ii) State the meaning of the symbol (aq).

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(iii) Why does the mass of the flask and contents decrease?

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(c) (i) Plot the results on the graph below and draw a smooth curve to show how the massof the flask and its contents changes with time. Label this curve A.

(3)

(ii) One of the results does not appear to fit the pattern. Circle this result on the graph.(1)

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(d) The student did a second experiment. The only change was that the acid was twice asconcentrated.

On the graph, sketch a second curve to show a possible result for this experiment. Labelthis curve B.

(2)

(Total 12 marks)

Q6. Acids and bases are commonly found around the home.

(a) Baking powder contains sodium hydrogencarbonate mixed with an acid.

(i) When water is added, the baking powder releases carbon dioxide. How could youtest the gas to show that it is carbon dioxide?

Test ..................................................................................................................

Result of test ....................................................................................................(2)

(ii) Complete and balance the chemical equation for the reaction of sodiumhydrogencarbonate with sulphuric acid.

NaHCO3 + H

2SO

4 ....................... + ........................ + ..................

(2)

(b) Indigestion tablets contain bases which cure indigestion by neutralising excess stomachacid.

(i) One type of indigestion tablet contains magnesium hydroxide. This base neutralisesstomach acid as shown by the balanced chemical equation.

Mg(OH)2

+ 2HCl MgCl2 + 2H

2O

Write a balanced ionic equation for the neutralisation reaction.

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(ii) How does the pH in the stomach change after taking the tablets?

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(c) Ammonium sulphate is used as a lawn fertiliser.

Using ammonia solution, describe how you would make the fertiliser ammonium sulphate.

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(Total 10 marks)

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C2 Patterns of Behaviour High