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(a) The diagram shows part of the Periodic Table.
Answer the following questions using only the symbol of the elements in the diagram. Each symbol may be used once, more than once or not at all.
State the symbol of the element that:
(i) is a fuel which is a gas at room temperature
.............................................................................................................. [1]
(ii) is used to kill bacteria in water
.............................................................................................................. [1]
(iii) forms a stable ion of type $X^{3+}$
.............................................................................................................. [1]
(iv) is a grey-black non-metallic solid at room temperature
.............................................................................................................. [1]
(v) forms an ion which, on addition of aqueous sodium hydroxide, gives a white precipitate which is soluble in excess aqueous sodium hydroxide.
.............................................................................................................. [1]
(b) Sulfur has several isotopes.
(i) Identify one correct statement about isotopes.
Tick one box.
□ They are molecules with the same number of neutrons but different numbers of protons.
□ They are atoms with the same number of protons but different numbers of neutrons.
□ They are molecules with the same number of protons but different numbers of electrons.
□ They are atoms with the same number of neutrons but different numbers of protons.
[1]
(ii) An isotope of sulfur is shown.
$^{33}_{16}S$
Deduce the number of protons and neutrons in this isotope.
number of protons ........................................................................................ [1]
number of neutrons ...................................................................................... [1]
(c) Complete the electronic structure of a sulfur atom.
[1]
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574
510
The table shows the mass of air pollutants, in nanograms, in $1000 \text{cm}^3$ samples of air taken over a four month period.
[Table_1]
(a) Answer these questions using only the information in the table.
(i) Name the pollutant that shows a decrease in concentration between August and November.
....................................................................................................................................... [1]
(ii) Calculate the mass of oxides of nitrogen in $250 \text{cm}^3$ of the sample of air taken in August.
................................. nanograms [1]
(b) Carbon monoxide is produced by the incomplete combustion of fossil fuels.
(i) State the meaning of the term incomplete combustion.
.......................................................................................................................................
....................................................................................................................................... [1]
(ii) Give one adverse effect of carbon monoxide on health.
....................................................................................................................................... [1]
(c) Carbon monoxide is also produced when methane reacts with steam in the presence of a catalyst.
(i) Explain why a catalyst is used in this reaction.
....................................................................................................................................... [1]
(ii) Methane is an air pollutant.
State one source of methane in the air.
....................................................................................................................................... [1]
(d) (i) Complete the chemical equation for the reaction of carbon monoxide with oxygen.
......CO + $O_2 \rightarrow$ ......$CO_2$ [2]
(ii) Complete the energy level diagram for the reaction of carbon monoxide with oxygen by writing these words on the diagram:
• reactants
• products.
[1]
(iii) Explain, using information on the energy level diagram, how you know that this reaction is exothermic.
....................................................................................................................................... [1]
(e) (i) Describe a test for carbon dioxide.
test .................................................................................................................................
result ............................................................................................................................. [2]
(ii) Identify which one of these pH values represents the pH of a solution of carbon dioxide in water.
Draw a circle around the correct answer.
pH 6 pH 7 pH 8 pH 14 [1]
581
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Some properties of four substances, A, B, C and D, are shown in the table.
[Table_1]
Answer these questions using only the information in the table.
(a) State which substance, A, B, C or D, is sulfur.
Explain your answer.
substance ........................................................................................................
explanation ......................................................................................................
[3]
(b) State which substance, A, B, C or D, is sodium chloride.
Explain your answer.
substance ........................................................................................................
explanation ......................................................................................................
[3]
512
569
504
The structure of crotonic acid is shown.
(a) (i) On the structure, draw a circle around the functional group which shows that this is an unsaturated compound. [1]
(ii) Deduce the formula of crotonic acid to show the number of carbon, hydrogen and oxygen atoms. [1]
(iii) Complete the table to calculate the relative molecular mass of crotonic acid. Use your Periodic Table to help you.[2]
(b) Acids react with bases such as calcium oxide.
Complete the word equation for the reaction of nitric acid with calcium oxide. [2]
(c) Calcium oxide is manufactured from limestone by thermal decomposition.
(i) Give the name of the main chemical compound in limestone. [1]
(ii) State the meaning of the term thermal decomposition. [2]
(d) Calcium oxide reacts with water to produce slaked lime.
State one use of slaked lime. [1]
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519
512
(a) Draw the structure of ethanol to show all of the atoms and all of the bonds.
[2]
(b) Ethanol is a liquid at room temperature.
Describe the motion and separation of the particles in ethanol.
motion ........................................................
separation ................................................. [2]
(c) Name the two products formed when ethanol undergoes complete combustion.
1 ...................................................................................................
2 ................................................................................................... [2]
(d) Ethanol can be manufactured by the fermentation of glucose.
One condition is using enzymes in yeast.
(i) State two other conditions for fermentation.
1 ...................................................................................................
2 ................................................................................................... [2]
(ii) Name the method used to separate the ethanol from the reaction mixture after fermentation is complete.
................................................................................................... [2]
(e) Alcohols can also be manufactured from alkenes.
Complete the word equation for the manufacture of ethanol by this method.
[2]
541
538
555
(a) Describe the electrolysis of concentrated hydrochloric acid.
In your answer include:
• a labelled diagram of the apparatus used for the electrolysis and collection of gases
• the names of the products formed at the positive and the negative electrode.
positive electrode .......................................................................................................................
negative electrode .......................................................................................................................
[5]
(b) Carbon dioxide is produced when hydrochloric acid reacts with sodium carbonate.
Complete the chemical equation for this reaction.
Na₂CO₃ + 2HCl → ......NaCl + ............ + CO₂
[2]
(c) Carbon dioxide reacts with carbon to produce carbon monoxide.
CO₂ + C → 2CO
Explain how this equation shows that carbon dioxide has been reduced.
...................................................................................................................
[1]
500
580
568
A student investigated the rate of reaction of excess calcium carbonate with dilute hydrochloric acid in a conical flask by two different methods.
Method 1: Measure the volume of carbon dioxide produced at 10 second intervals.
Method 2: Measure the loss in mass of the reaction mixture by weighing at 10 second intervals.
(a) (i) Suggest one advantage of Method 1 compared with Method 2. [1]
(ii) Explain why there is a decrease in mass of the reaction mixture in Method 2. [1]
(b) The graph shows how the volume of carbon dioxide changes as the reaction proceeds, using Method 1.
The student used large pieces of calcium carbonate.
Answer these questions using information from the graph.
(i) Describe how the rate of this reaction changes with time. [1]
(ii) Deduce the time taken to collect 36 cm^3 of carbon dioxide. [1]
(iii) The experiment is repeated using smaller pieces of calcium carbonate.
Draw a line on the grid to show how the volume of carbon dioxide changes with time when smaller pieces of calcium carbonate are used.
All other conditions stay the same. [2]
(iv) Describe what effect the following changes have on the rate of this reaction. [2]
● The temperature is increased.
All other conditions stay the same.
● The concentration of the hydrochloric acid is decreased.
All other conditions stay the same.
509
531
577
(a) (i) Sodium is a metal in Group I of the Periodic Table. Identify two correct statements about sodium. Tick two boxes.
- It is a relatively soft metal.
- It has a high melting point.
- It forms coloured chlorides.
- It has a lower density than most metals.
- It is a good insulator.
(a) (ii) Some changes of state of sodium are shown.
[Image_1: Diagram showing changes of state]
Give the names of the changes of state represented by R and S.
R ...........................................................
S ...........................................................
(b) The table compares the reactions of four metals with dilute and with concentrated hydrochloric acid.
[Table_1: Metal reactions table]
Put the four metals in order of their reactivity. Put the least reactive metal first.
least reactive ................................................... most reactive
(c) Crystals of magnesium chloride, MgCl$_2$·6H$_2$O, can be prepared by adding excess magnesium powder to dilute hydrochloric acid.
Describe how to prepare a sample of pure dry magnesium chloride crystals after the reaction is complete.
In your answer describe how to:
- remove the excess magnesium from the reaction mixture
- crystallise the magnesium chloride
- dry the crystals.
(d) When magnesium reacts with concentrated sulfuric acid, sulfur dioxide is produced.
Complete this description of the test for sulfur dioxide using words from the list.
blue chloride colourless
green manganate(VII) sulfate(VI)
The test for sulfur dioxide uses acidified aqueous potassium .......................................... .
The colour change is from purple to .......................................... .
(e) (i) Green nickel(II) sulfate crystals turn yellow when heated.
NiSO$_4$·7H$_2$O $
ightleftarrows$ NiSO$_4$ + 7H$_2$O
(green) (yellow)
nickel(II) sulfate nickel(II) sulfate
Suggest how you would change yellow nickel(II) sulfate to green nickel(II) sulfate.
(e) (ii) Identify which word best describes green nickel(II) sulfate with the formula NiSO$_4$·7H$_2$O.
Draw a circle around the correct answer.
anhydrous decomposed hydrated oxidised reduced
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