Exam code: 5070
Complete the chemical equation for the complete combustion of propene.
2C3H6 + ......O2 → 6CO2 + 6H2O
Describe a test for carbon dioxide.
test ..................................................
observations ..................................................
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A list of symbols and formulae is shown.
CH4
Cl–
CO2
Cr3+
Cu2+
Fe2+
H2
K+
N2
O2
SO2
Which symbol or formula represents an ion which forms a blue precipitate when added to aqueous sodium hydroxide.
A solution is obtained by filtering a mixture of soil and water. The table shows the mass of some of the ions in 1000 cm3 of this solution.
name of ion | formula of ion | mass of ion in 1000 cm3 of soil solution / mg |
aluminium | Al3+ | 0.2 |
| NH4+ | 22.0 |
calcium | Ca2+ | 0.2 |
iron(II) | Fe2+ | 79.0 |
magnesium | Mg2+ | 0.1 |
nitrate | NO3– | 28.0 |
phosphate | PO43– | 14.0 |
potassium | K+ | 39.0 |
| SO42– | 5.1 |
State the name of the SO42– ion.
Describe a chemical test for calcium ions.
test ______________________________________
observations ______________________________
Hydrogen is produced when a metal reacts with an acid.
Describe a test for hydrogen.
test .....................................................................................
observations .....................................................................
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Describe a test for iron(II) ions.
test _________________________________
observations _________________________
Describe a test for bromide ions.
test ___________________________
observations ___________________
Nitric acid contains nitrate ions.
Complete these sentences about the test for nitrate ions using words from the list.
aluminium ammonia blue chloride copper green iron nitrate oxygen red
Aqueous sodium hydroxide and _____________________ foil are added to the solution being tested. The mixture is warmed gently. The _________________ produced turns damp ___________________ litmus paper __________________ .
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Hydrogen peroxide, H2O2, decomposes slowly to form water and oxygen.
Write the word equation for this reaction.
The decomposition of hydrogen peroxide also occurs in the presence of a manganese(IV) oxide, MnO2, catalyst.
What is meant by the term catalyst?
Bubbles of oxygen gas are produced when manganese(IV) oxide is added to hydrogen peroxide.
Describe a test for oxygen gas.
test .....................................................
observations ........................................................
The decomposition of hydrogen peroxide is exothermic.
What is meant by the term exothermic?
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A white solid X contains ammonium ions.
Describe the test you would carry out on a solution of X to show that it contains ammonium ions.
Give the result of the test.
A solution of X is acidified with dilute nitric acid. Aqueous barium nitrate is then added. A white precipitate forms.
Name the anion present in X.
Name the white precipitate.
Give the name of X.
A solution of a different compound Z also gives a white precipitate when dilute nitric acid and aqueous barium nitrate are added.
When aqueous sodium hydroxide is added to a solution of Z, a green precipitate forms. The precipitate dissolves when the aqueous sodium hydroxide is in excess, giving a green solution.
Name the cation present in Z.
Give the name of Z.
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Choose a gas from the following list to answer the questions below.
Each gas may be used once, more than once or not at all.
ammonia | carbon dioxide | carbon monoxide | fluorine |
krypton | nitrogen | propene | hydrogen |
It polymerises to form a poly(alkene).
It is a noble gas.
It is the main component of air.
It is a very reactive non-metal.
It burns to form water as the only product.
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Choose a gas from the following list to answer the questions below. Each gas may be used once, more than once or not at all.
ammonia argon chlorine ethene hydrogen
carbon dioxide nitrogen carbon monoxide oxygen
Which gas
i) Is a noble gas?
[1]
ii) Is an acidic oxide?
[1]
iii) Can be polymerised?
[1]
iv) Is the active component of air?
[1]
v) Is used in the treatment of water?
[1]
Complete the following table.
Gas | Test for Gas |
Ammonia |
|
| Bleaches damp litmus paper |
Hydrogen |
|
| Relights a glowing splint |
| Turns limewater milky |
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Table 1 shows the mass of ions present in a 100 cm3 sample of milk. Table 1
ion | formula of ion | mass of ion in 100 cm3 milk / mg |
calcium | Ca2+ | 125 |
chloride | Cl − | 120 |
magnesium | Mg2+ | 12 |
negative ions of organic acids |
| 160 |
phosphate | PO43− | 95 |
potassium | K+ | 140 |
sodium | Na+ | 58 |
sulfate | SO42− | 30 |
Describe a test for chloride ions.
test ..................................................
positive result ..................................................
Calcium reacts with cold water to form two products:
a colourless gas, P, which ‘pops’ with a lighted splint
a weakly alkaline solution, Q, which turns milky when carbon dioxide is bubbled through it.
i) Name gas P.
[1]
ii) Name the weakly alkaline solution Q.
[1]
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This question is about ammonia and ammonium salts.
Ammonia is a gas at room temperature.
What is the test for ammonia gas?
Describe the positive result of this test.
test .......................................................................
result ....................................................................
Ammonia reacts with water to form ions.
NH3 + H2O NH4+ + OH–
Describe what is seen when aqueous ammonia is added to aqueous copper(II) sulfate, until no further change is seen.
Barium sulfate is an insoluble salt.
Barium sulfate can be made from aqueous ammonium sulfate using a precipitation reaction.
Name a solution that can be added to aqueous ammonium sulfate to produce a precipitate of barium sulfate.
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This question is about tests for ions.
Describe the test for a nitrate ion.
test ___________________________
result __________________________
Describe a test for iodide ions.
test ______________________________
observations ______________________
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Copper reacts with concentrated nitric acid to form copper(II) nitrate.
Cu (s) + 4HNO3 (aq) → Cu(NO3)2 (aq) + 2NO2 (g) + 2H2O (l)
State the meaning of (aq).
An excess of copper is added to 25.0 cm3 of 16.0 mol / dm3 HNO3.
Use this information, together with the equation, to calculate the volume of NO2 formed. The gas volume is measured at room temperature and pressure.
Show your working and state the units.
When heated, Cu(NO3)2 decomposes to form CuO, NO2 and O2.
Construct the symbol equation for this reaction.
To a small sample of Cu(NO3)2 (aq), a student adds aqueous ammonia drop by drop until it is in excess.
i) Describe what is observed.
[2]
ii) The student repeats the experiment but adds aqueous sodium hydroxide instead of aqueous ammonia. Describe what is observed.
[1]
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A student tests two substances, solution C and solid D.
Tests on solution C
Solution C is aqueous potassium carbonate.
The student divides solution C into two approximately equal portions in two test-tubes. Record the expected observation.
To the first portion of solution C, about 10 cm3 of dilute hydrochloric acid is added.
Observation:
The student does a flame test on the second portion of solution C.
i) State the expected colour of the flame.
[1]
ii) Describe how to do a flame test.
[2]
Tests on solid D
Table 3.1 shows the tests and the student's observations for solid D.
Table 3.1
tests | observations |
test 1 Do a flame test on solid D. | orange-red colour |
test 2 The remaining solid D is dissolved in distilled water to form solution D. Solution D is divided into two portions. To the first portion of solution D, aqueous ammonia is added dropwise and then in excess. | very slight white precipitate |
test 3 To the second portion of solution D, add about 1 cm3 of dilute nitric acid followed by a few drops of aqueous silver nitrate. | yellow precipitate |
Identify the two ions present in the solid
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An investigation into how the rate of reaction is affected by temperature is completed using the apparatus shown.
The time taken for the magnesium to stop reacting is measured.
i) Describe a test for the gas produced, including the positive observation, during this reaction.
[2]
ii) Give the balanced symbol equation for the reaction that occurs during the gas test.
[2]
State and explain what would happen to the rate of reaction between magnesium and hydrochloric acid as the temperature increased.
[4]
2.0 g of magnesium reacted with 25.0 cm3 of 1.0 mol / dm3 hydrochloric acid is reacted at room temperature and pressure.
The chemical equation for this reaction is
Mg + 2HCl → MgCl2 + H2
Calculate the volume of hydrogen gas that would be produced in this reaction. Give your answer in dm3.
[6]
The student repeated the experiment but used a white powder, compound X, instead of magnesium.
A gas was produced during the reaction with hydrochloric acid. When the gas was bubbled through limewater, it turned cloudy.
The student carried out a flame test on compound X and a lilac flame was produced.
Give the formula of compound X. Explain your answer.
[3]
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Three substances A, B and C were each shaken with water, and the mixtures were tested.
tests | observations |
Test 1 A flame test was done on each mixture | A produced a green flame, B produced a red flame and C produced a yellow flame |
Test 2 Dilute hydrochloric acid was added to each mixture | A fizzed, there was no reaction with B or C |
Test 3 Sodium hydroxide solution was added to each mixture | A formed a blue precipitate, B formed a white precipitate and C did not form a precipitate |
Test 4 Dilute hydrochloric acid and barium chloride were added to each mixture | A fizzed but did not form a precipitate, C formed a white precipitate and B did not react |
Test 5 Dilute nitric acid and silver nitrate were added to each mixture | A and C did not react, B formed a cream precipitate |
Identify the two ions present in each of A, B and C.
What is the purpose of adding dilute acid in the tests with barium chloride and silver nitrate?
Suggest what would be seen if the acid was not added.
Explain why nitric acid is used before using silver nitrate instead of hydrochloric acid or sulfuric acid.
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A student investigates the mass of dissolved salts in 50 cm3 of an unknown solution. The solution is thought to contain sodium chloride and sodium carbonate.
The tests and some of the observations from the student's investigation are in the following table.
tests | observations |
Test 1: A flame test was carried out on the unknown solution |
|
Test 2: An excess of dilute nitric acid was added to the unknown solution | effervescence 0.408 dm3 of gas was collected using a gas syringe |
Test 3: Aqueous silver nitrate was added to the unknown solution | White precipitate |
Test 4: The white precipitate was filtered, dried and weighed | mass = 1.380 g |
Describe how the student should perform the flame test and include the expected result.
Explain why hydrochloric acid and sulfuric acid should not be used in test 2. Use chemical equations, including state symbols, to support your answer.
Hydrochloric acid
Reaction equation ................................................................................
Explanation ................................................................................
Sulfuric acid
Reaction equation ................................................................................
Explanation ................................................................................
[5]
The original apparatus used by the student consisted of a thistle funnel containing excess nitric acid connected to a conical flask of the unknown solution. The conical flask was also directly connected to a gas syringe to measure the volume of gas produced during test 2.
The student suggested that test 2 could be improved by including a second conical flask containing limewater before the gas syringe as shown.
i) Explain one advantage and one disadvantage of the student's suggested apparatus instead of the original apparatus.
Advantage ............................................................
Disadvantage ............................................................
[4]
ii) Use the results of test 2 to calculate the mass of sodium carbonate present in the unknown solution.
[2]
i) Give the ionic equation to show the formation of the white precipitate in test 3.
[1]
ii) Use the results of test 4 to calculate the mass of sodium chloride present in the unknown solution.
[3]
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A bottle in a school store cupboard has lost its label. The bottle contains a white solid.
A student carries out a flame test on the solid. The student holds a sample of the solid in the flame on a wooden splint.
The flame turns red. A few seconds later the flame turns yellow.
The student concludes that the solid contains sodium ions.
Explain why the yellow colour does not show that the solid contains sodium ions.
The student records the first flame colour as red, but is not sure of the exact shade of red.
Name the two cations that could have given this flame colour.
Explain why the flame test on its own does not show which of them is present.
The student dissolves some of the solid in water.
Aqueous sodium hydroxide is added to the solution a little at a time, and then in excess.
A white precipitate forms. The precipitate does not dissolve when the aqueous sodium hydroxide is in excess.
Deduce which cation the solid contains.
Explain how the result with aqueous sodium hydroxide and the result of the flame test together allow you to decide.
A second bottle in the store cupboard contains a different white solid.
A flame test on this second solid produces a light green flame.
A student concludes that this solid contains copper(II) ions.
Name the cation that produces a light green flame.
State the flame colour produced by copper(II) ions.
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A student is given an aqueous solution Q. Q contains one anion.
The student adds a small volume of acidified aqueous potassium manganate(VII) to Q. The purple colour of the manganate(VII) changes to colourless.
Name the anion present in Q.
The student warms a second sample of Q with dilute hydrochloric acid and collects the gas given off.
The gas turns acidified aqueous potassium manganate(VII) from purple to colourless.
Name the gas.
Explain why this result is consistent with your answer to part (a).
A different aqueous solution R is tested with acidified aqueous potassium manganate(VII). There is no colour change.
State what this result shows about R.
Explain why it does not identify the anion in R.
Name one other anion that R could contain together with a test, and its result, that would identify it.
A different solution may contain both sulfite ions and carbonate ions.
Explain why the student should test this solution for carbonate ions before adding acidified aqueous potassium manganate(VII) to it.
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