11 questions · 110 marks · ≈ 2 hours
The diagram shows the particles in four substances, A, B, C and D
Which substance contains single atoms of one element? A B C D
Which substance is a compound? A B C D
Which substance could have the formula H₂? A B C D
The diagram shows the particles in substance E. E Give two reasons why substance E is a mixture. 1 2
This question is about Group 7 elements and their reactions.
Fluorine has the smallest atoms in Group 7. The diagram shows the electronic configuration of a fluorine atom.
State why fluorine has the smallest atoms in Group 7.
Which row gives the correct number of occupied electron shells and the correct number of outer shell electrons in an atom of iodine? Use the Periodic Table on page 2 to help you. Number of Number of occupied electron shells outer shell electrons
Choose your answer
4 5
5 6
5 7
7 5
The table gives descriptions of the reactions of some Group 7 elements with iron wool. Complete the table by giving a description of the reaction of fluorine with iron wool. Element Description of reaction with iron wool fluorine • does not need heating chlorine • reacts quickly • needs heating bromine • reacts slowly • needs heating iodine • reacts very slowly
State the relationship between the reactivity of the Group 7 elements and the size of their atoms.
This question is about the rusting of iron.
Water is needed for iron to rust.
Name one other substance needed for iron to rust.
Give the chemical name for rust.
The diagram shows two methods used to prevent iron from rusting. iron plastic iron zinc Method A Method B Method A will only work if the plastic coating is not damaged. Method B will work even when the zinc coating is damaged.
Explain how method A prevents iron from rusting.
Give the name of method B.
Explain how method B prevents iron from rusting even when the zinc coating is damaged.
The table shows the number of protons, neutrons and electrons in species F, G and H. Species F Species G Species H number of protons 7 7 7 number of neutrons 7 8 7 number of electrons 7 7 10
Give the mass number of F.
Give the electronic configuration of G.
Explain why F and G are isotopes of the same element. Refer to subatomic particles in your answer.
Explain why H is a negative ion. Refer to subatomic particles and their charges in your answer.
A sample of carbon contains atoms of mass number 12 and 13 The table shows the percentages of these atoms in the sample. Mass number Percentage (%) 12 98.930 13 1.070 Calculate the relative atomic mass (Ar) of this sample of carbon. Give your answer to two decimal places. relative atomic mass =
Two experiments are done to determine the percentage composition by volume of a mixture of three gases, carbon dioxide, oxygen and argon.
In experiment 1, a student bubbles the mixture of gases through limewater. Carbon dioxide reacts with limewater. The diagram shows the apparatus the student uses. syringe A syringe B mixture of gases gas syringe in 1 cm³ divisions limewater The student pushes the mixture of gases out of syringe A, but no gas bubbles appear in the limewater. Give one change the student needs to make to the apparatus for gas bubbles to appear in the limewater.
When the apparatus in experiment 1 is set up correctly, the mixture of gases is bubbled gently through the limewater so that all the carbon dioxide is removed. The volume of the mixture of gases in syringe A at the start is 76 cm³. The volume of the mixture of gases in syringe B at the end is 66 cm³.
Calculate the percentage by volume of carbon dioxide in the mixture of gases in syringe A. percentage of carbon dioxide = %
Give the change in the appearance of the limewater.
Explain why the gas syringes in experiment 1 cannot be used to find the percentage of carbon dioxide in a typical sample of air.
In experiment 2, a teacher pushes the remaining gases over hot copper powder. The diagram shows the apparatus the teacher uses. copper powder gas syringe HEAT The copper powder turns black as it reacts with oxygen. Argon is extremely unreactive, so it does not react with copper.
Name the black substance that forms on the copper powder.
Suggest why the teacher uses copper powder instead of the same mass of large pieces of copper.
Explain why argon is extremely unreactive.
This question is about organic compounds.
The diagram shows the displayed formulae of five compounds, U, V, W, X and Y
Give the letter of the compound that is not a hydrocarbon.
Give the letter of the compound that is a saturated hydrocarbon with the empirical formula CH₂
Give the letter of the compound that reacts with bromine in the presence of ultraviolet radiation to form this structure.
Give the letter of the compound that forms an addition polymer with this repeat unit.
Give the displayed formula of an alkene that is an isomer of compound X.
Compounds U and X are members of the same homologous series. Members of the same homologous series have the same functional group. Give two other characteristics of compounds in the same homologous series. 1 2
Compound Z contains 38.7% carbon, 9.7% hydrogen and 51.6% oxygen by mass.
Show by calculation that the empirical formula of compound Z is CH₃O
The relative formula mass (Mr) of compound Z is 62 Deduce the molecular formula of compound Z. molecular formula =
This question is about nitrogen and some of its compounds.
Nitrogen and oxygen do not react together at room temperature. At the high temperatures in a car engine, nitrogen and oxygen react to form nitrogen monoxide, NO
Give a chemical equation for this reaction.
Give a reason why this reaction only occurs at high temperatures.
State why it is important that oxides of nitrogen are not released into the atmosphere.
Nitrogen monoxide gas can be removed from car exhaust fumes when it reacts with carbon monoxide gas.
The rate of the reaction is increased by passing the gases over a catalyst. Explain how a catalyst increases the rate of a reaction.
Explain how increasing the pressure of gases increases the rate of reaction.
Ammonia is a simple molecule with the formula NH₃
Complete the diagram to show the outer shell electrons in ammonia. N H H H
The bonds in ammonia are covalent. Describe the forces of attraction in a covalent bond.
Explain why ammonia has a low boiling point.
This question is about barium chloride.
Barium chloride can be made by reacting barium carbonate with dilute hydrochloric acid. The chemical equation for the reaction is BaCO₃(s) + 2HCl(aq) → BaCl₂(aq) + H₂O(l) + CO₂(g) Describe a method to produce dry crystals of hydrated barium chloride, starting with barium carbonate powder and dilute hydrochloric acid.
A colourless solution contains sodium carbonate and sodium sulfate. Describe a test using barium chloride to show that the colourless solution contains sulfate ions.
A student investigates the reaction between solid hydrated sodium carbonate and dilute hydrochloric acid.
She uses this method to investigate the temperature change during the reaction. Step 1 pour 25.0 cm³ of dilute hydrochloric acid into a polystyrene cup Step 2 record the temperature of the dilute hydrochloric acid Step 3 add 0.5 g of sodium carbonate and stir the mixture Step 4 record the lowest temperature of the mixture Step 5 add further 0.5 g portions of sodium carbonate, one portion at a time, stir the mixture and record the lowest temperature each time The table shows the student’s results. Mass of sodium carbonate Temperature in °C added in g 0.0 17.0 0.5 15.6 1.0 14.1 1.5 13.0 2.0 12.9 2.5 12.2 3.0 11.8 3.5 11.5 4.0 11.2 4.5 11.0 5.0 11.0
Plot the student’s results on the grid.
Draw a curve of best fit, ignoring the anomalous result. Temperature in °C 0 1 2 3 4 5 Mass of hydrated sodium carbonate added in g
Explain why it is better to use a polystyrene cup instead of a glass beaker in this experiment.
Suggest a reason for the anomalous result.
State how the results show that all the dilute hydrochloric acid has reacted.
Use the results of the experiment to explain the type of reaction that occurs when sodium carbonate is added to dilute hydrochloric acid.
The student does another experiment using the same reaction. The diagram shows the student’s apparatus. cotton wool sodium carbonate dilute hydrochloric acid balance g The mass on the balance decreases as carbon dioxide gas escapes.
Give a reason for the cotton wool plug in the conical flask.
The student adds 2.12 g of sodium carbonate to an excess of dilute hydrochloric acid. The chemical equation for the reaction is Na₂CO₃(s) + 2HCl(aq) → 2NaCl(aq) + H₂O(l) + CO₂(g) Calculate the maximum mass, in g, of carbon dioxide formed in the reaction. mass = g
Suggest why the mass of carbon dioxide produced is less than the calculated maximum mass.
A teacher uses this apparatus to separate a mixture of ethanol and water
Name this method of separation.
Name the change of state taking place at A.
Name the change of state taking place at B.
The mixture contains 15.5 cm³ of ethanol. 1.0 cm³ of ethanol has a mass of 0.79 g. One mole of ethanol contains 6.00 × 10²³ molecules. [Mr of ethanol = 46]
Calculate the amount, in moles, of ethanol in 15.5 cm³ of ethanol. amount = mol
Calculate the number of molecules of ethanol in 15.5 cm³ of ethanol. number of molecules =
After five minutes, the teacher collects a sample of colourless liquid in a new beaker.
Describe a chemical test to show that the colourless liquid contains water.
Describe a physical test to show if the colourless liquid is pure water.
The teacher uses this apparatus to heat 100 g of water. copper can 100 g of water burner ethanol He records the temperature of the water before and after heating. temperature of water before heating = 21.0 °C temperature of water after heating = 70.5 °C
Calculate the heat energy change (Q) in joules. [specific heat capacity of water is 4.2 J/g/°C] Q = J
The student burns 0.0200 mol of ethanol. Use this information and your value for Q to calculate the molar enthalpy change (ΔH), in kJ/mol, for the combustion of ethanol. Include a sign in your answer. ΔH = kJ/mol
This question is about the reactivity of metals.
Table 1 shows whether a reaction occurs between a metal and an aqueous solution of a metal sulfate. Metal Metal sulfate Does a reaction occur? manganese chromium sulfate yes tin cadmium sulfate no chromium cadmium sulfate yes Table 1
Name the type of reaction that occurs between manganese and chromium sulfate.
Use the information in Table 1 to complete the order of reactivity. most reactive manganese least reactive
Table 2 shows the colours of four metals and the colours of their metal sulfate solutions. Metal Colour of metal Colour of metal sulfate solution copper brown blue iron dark grey green magnesium silvery colourless zinc light grey colourless Table 2 When a metal is added to a metal sulfate solution there may be a colour change on the surface of the metal and in the solution. Use the information in Table 2 and your knowledge of the reactivity series to explain any colour changes in these two experiments. copper added to magnesium sulfate solution zinc added to iron sulfate solution
A different experiment can be used to place metals in order of reactivity. This is the method. Step 1 add 1 g of a metal to 25 cm³ of dilute sulfuric acid Step 2 measure the volume of gas produced in one minute
Give two variables that should be controlled in this experiment. 1 2
A small piece of calcium is added to some dilute sulfuric acid in a beaker. One of the products of the reaction, calcium sulfate, is insoluble in water. Suggest why the reaction stops after a short time, even though the beaker still contains calcium and dilute sulfuric acid.
1.00 g of aluminium is added to 0.0600 mol of dilute sulfuric acid. The equation for the reaction is 2Al(s) + 3H₂SO₄(aq) → Al₂(SO₄)₃(aq) + 3H₂(g) Show by calculation that the sulfuric acid is in excess.