0620_s14_qp_23
A paper of Chemistry, 0620
Questions:
8
Year:
2014
Paper:
2
Variant:
3
Login to start this paper & get access to powerful tools
1
Choose from the list of compounds below to answer the following questions. aluminium oxide calcium carbonate calcium oxide copper(sulfate hydrogen chloride potassium bromide sodium chloride sodium hydroxide Each compound can be used once, more than once or not at all. Which compound: reacts with aqueous ammonia to form a light blue precipitate, is formed by the decomposition of limestone, forms an acidic solution when dissolved in water, when electrolysed, gives a red-brown vapour at the anode, is an oxide of a metal in Group III of the Periodic Table, is a transition element compound? Complete the following sentences about compounds using words from the list below. chemically different fi xed mixed physically similar A compound is a substance which consists of two or more different elements combined together. The properties of a compound are from those of the elements from which it is formed. In a compound, the elements are combined in proportions.
2. Atoms, elements and compounds  →  2.1. Elements, compounds and mixtures
3. Stoichiometry  →  3.1. Formulae
8. The Periodic Table  →  8.4. Transition elements
Open
2
Calcium chloride, CaCl 2, is a salt. Suggest the name of an acid and a base that would react together to make calcium chloride. acid base Calcium chloride absorbs water vapour. When calcium chloride is heated, it loses its water of crystallisation. Complete the symbol equation for this reaction. Include the sign for a reversible reaction. CaCl 2.6H2O CaCl 2 + A student put some clean iron nails in two test-tubes, as shown in the diagram. She then left the test-tubes for several weeks. A B anhydrous calcium chloride CaCl 2 cotton wool cotton wool Explain why the nails in tube A did not rust but the nails in tube B rusted. Rust is hydrated iron(oxide. What does the (in iron(oxide refer to? Tick one box. the oxidation state of the oxygen the oxidation state of the iron the number of atoms of oxygen in a formula unit of iron(oxide the number of water molecules in the hydrated iron oxide The table describes the ease of reduction of some metal oxides with carbon monoxide. lead oxide moderate heating to about 200 °C needed iron oxide high temperature furnace at 750 °C needed magnesium oxide temperatures above 1000 °C needed zinc oxide very high temperature furnace at 900 °C needed Put these metals in order of their reactivity with carbon monoxide. least reactive most reactive Some metal oxides can be reduced by heating with hydrogen gas. CuO + H2 → Cu + H2O Explain how this equation shows that copper oxide is being reduced.
9. Metals  →  9.4. Reactivity series
9. Metals  →  9.5. Corrosion of metals
9. Metals  →  9.6. Extraction of metals
Open
3
The diagram shows the best pH ranges for growing different plants. pH beans carrots clover potatoes tomatoes Which two plants grow best in acidic conditions only? and Which pH shown in the diagram above represents a neutral pH? Explain why lime is added to acidic soils. Farmers fertilise soil by adding compounds containing ammonium salts. Explain why adding lime to fertilised soil may cause a loss of nitrogen from the soil. The graphs below show the rate of uptake of potassium and phosphate ions by plant roots at different pH values. pH rate of uptake of potassium pH 10 11 rate of uptake of phosphorus Describe the effect of pH on the rate of uptake of potassium by plant roots. At which pH value is the rate of uptake of phosphorus by plant roots the highest?
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
10. Chemistry of the environment  →  10.2. Fertilisers
Open
4
Chromatography is used to separate a mixture of coloured dyes. Three different dye mixtures, A, B and C, were spotted onto a piece of chromatography paper. Two pure dyes, X and Y, were also spotted onto the same piece of paper. The diagram below shows the results of the chromatography. A B C X Y solvent front base line State the name of a piece of apparatus that could be used to spot the dyes onto the paper. Suggest why the base line was drawn in pencil and not in ink. Which dye mixture contains both dye X and dye Y? Which dye mixture does not contain dye X or dye Y? In which mixture, A, B or C, has the greatest number of dyes been separated? The structure of the dye chrysoidine G is shown below. C C C C C C C N N N H H H H H C C C C C H H H H H N H H How many nitrogen atoms are there in a molecule of chrysoidine G? Complete the table below to calculate the relative molecular mass of chrysoidine G. type of atom number of atoms atomic mass carbon 12 × 12 = 144 hydrogen nitrogen relative molecular mass = The fi bres in the chromatography paper are polymers. What is meant by the term polymer? State the chemical name of the polymer formed from ethene.
12. Experimental techniques and chemical analysis  →  12.3. Chromatography
11. Organic chemistry  →  11.8. Polymers
Open
5
The table shows some properties of the fi rst four carboxylic acids. acid molecular formula melting point / °C boiling point / °C density in g / cm3 methanoic acid CH2O2 +10 +101 1.22 ethanoic acid C2H4O2 +17 +118 1.05 propanoic acid C3H6O2 –21 0.99 butanoic acid C4H8O2 – 4 +166 How does the boiling point of these carboxylic acids vary with the number of carbon atoms? Suggest a value for: the boiling point of propanoic acid, °C the density of butanoic acid. g / cm3 Is butanoic acid a solid, liquid or gas at room temperature? Use the data in the table to explain your answer. Complete the diagram below to show the structure of ethanoic acid. Show all atoms and bonds. H C H H C The concentration of ethanoic acid can be determined by titration using the apparatus shown below. A B ethanoic acid State the name of the piece of glassware labelled A. Liquid B is an alkali. Which one of the following compounds is also an alkali? Put a ring around the correct answer. calcium carbonate calcium sulfate sodium chloride sodium hydroxide Describe how you would carry out this titration.
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
11. Organic chemistry  →  11.7. Carboxylic acids
Open
6
Lead(bromide is a white solid. Part of the structure of lead(bromide is shown below. Br – Br – Br – Br – Pb2+ Br – Br – Br – Br – Pb2+ Br – Br – Pb2+ Br – Br – Pb2+ Pb2+ Pb2+ Deduce the simplest formula for lead(bromide. A student electrolysed lead(bromide in a fume cupboard using the apparatus shown below. anode cathode lead(bromide Why is heat needed for this electrolysis? Suggest the name of a substance that could be used for the electrodes. State the name of the products of electrolysis at: the anode, the cathode. Items can be electroplated with silver using the apparatus shown below. B C A D rod of silver alloy rod electrolyte + – On the diagram, which letter, A, B, C or D, is the cathode? What would you observe during the experiment at the: positive electrode, negative electrode? The electrolyte used is aqueous silver cyanide, AgCN. Calculate the relative formula mass of silver cyanide. You must show all your working.
4. Electrochemistry  →  4.1. Electrolysis
Open
7
Dmitri Mendeleev published his fi rst Periodic Table in 1869. Part of this table is shown below. Ti = 50 V = 51 Cr = 52 Mn = 55 Fe = 56 Co = 59 H = 1 Cu = 63.4 Be = 9.4 Mg = 24 Zn = 65.2 B = 11 Al = 27.4 ? C = 12 Si = 28 ? N = 14 P = 31 As = 75 O = 16 S = 32 Se = 79.4 F = 19 Cl = 35.5 Br = 80 Li = 7 Na = 23 K = 39 Rb = 85.4 What differences are there between Mendeleev’s table and the Periodic Table we use today? State the names of any two elements in the table above which exist as diatomic molecules. and Titanium is a transition element. Sodium is a metal in Group I of the Periodic Table. State three differences in the physical properties of titanium and sodium. Titanium(oxide reacts with a mixture of chlorine and carbon. The products are titanium(chloride, TiCl 4, and a gas which turns limewater milky. Complete the symbol equation for this reaction. TiO2 + Cl 2 + C → TiCl 4 + Titanium is extracted from titanium(chloride by reduction with molten sodium in the presence of argon. Suggest why this reaction is carried out in the presence of argon.
8. The Periodic Table  →  8.1. Arrangement of elements
8. The Periodic Table  →  8.3. Group VII properties
Open
8
Sodium sulfate is a solid with a high melting point. Sodium sulfate conducts electricity when molten but not when solid. What type of structure is sodium sulfate? Tick one box. structure of separated atoms simple molecular structure giant ionic structure giant covalent structure Describe a test for sulfate ions. test result Describe how simple distillation is used to separate water from an aqueous solution of sodium sulfate. In your answer, refer to: ● the apparatus used, ● changes in state, ● differences in boiling points. You may use a diagram. What would you observe when a piece of blue cobalt chloride paper is dipped into water? Describe how impure water is treated so that it can be used for drinking.
10. Chemistry of the environment  →  10.1. Water
2. Atoms, elements and compounds  →  2.4. Ions and ionic bonds
Open