0620_m17_qp_32
A paper of Chemistry, 0620
Questions:
7
Year:
2017
Paper:
3
Variant:
2
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1
Choose from the list of elements to answer the following questions. aluminium argon carbon lithium magnesium nickel nitrogen oxygen sulfur Each element can be used once, more than once or not at all. Which element forms 21% of dry air, reacts rapidly with cold water to produce hydrogen, is in Group III of the Periodic Table, has atoms which have a complete outer shell of electrons, is a transition element, forms stable ions with a single positive charge? Complete the table to show the number of electrons, neutrons and protons in the nickel atom and oxide ion shown. number of electrons number of neutrons number of protons 62Ni 18O 2–
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
8. The Periodic Table  →  8.1. Arrangement of elements
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2
The diagram shows a blast furnace for extracting iron. mixture of iron ore, coke and limestone (calcium carbonate) slag molten iron On the diagram write ● the letter A to show where air is blown into the furnace, ● the letter W to show where waste gases exit the furnace. How do you know from the information in the diagram that slag is less dense than molten iron? Limestone (calcium carbonate) is one of the raw materials added to the blast furnace. Calcium carbonate undergoes thermal decomposition in the blast furnace. What is meant by the term thermal decomposition? Complete the chemical equation for this reaction. CaCO3 CaO + A further reaction in the blast furnace involves calcium oxide, CaO. Describe this reaction and explain its importance. Pure iron can be prepared by electrolysis of an aqueous solution of a suitable iron(salt. Draw a labelled diagram of an electrolysis cell that could be used to carry out this reaction. In your diagram include ● the electrodes, ● the electrolyte, ● the power supply. State the name of an element that could be used for the electrodes. State one property that an electrode should have. Pure iron can also be prepared by the thermal decomposition of iron pentacarbonyl. The structure of iron pentacarbonyl is shown. Fe C C C C C O O O O O Write the formula for iron pentacarbonyl. The word equation for the reaction is shown. iron pentacarbonyl iron + carbon monoxide Explain why the gaseous product is hazardous. The rate of rusting of iron varies with pH and temperature. What two substances must be in contact with iron for it to rust? The graph shows the rate of rusting at different pH values and temperatures. mass of rust / g time / hours pH 4, 30 °C pH 4, 20 °C pH 7, 30 °C pH 8, 30 °C pH 7, 20 °C pH 8, 20 °C How do pH and temperature affect the rate of rusting? pH temperature
9. Metals  →  9.6. Extraction of metals
4. Electrochemistry  →  4.1. Electrolysis
9. Metals  →  9.4. Reactivity series
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3
The hydrocarbons burnt in car engines react with air to form a mixture of gases. The table shows the composition of the mixture of all the gases coming from a car exhaust. gas % of gas in the exhaust gases carbon dioxide carbon monoxide hydrocarbons hydrogen nitrogen oxides oxygen water vapour gas X Identify gas X. Carbon dioxide is formed when hydrocarbons such as octane are burnt in car engines. What is meant by the term hydrocarbon? Complete the word equation for this reaction. octane + carbon dioxide + The concentration of carbon dioxide in the atmosphere is increasing. Explain why this is a global concern. Explain why carbon monoxide is present in the exhaust gases. Complete the table to calculate the relative molecular mass of octane, C8H18. number of atoms relative atomic mass relative mass in octane hydrogen 18 × 1 = 18 carbon relative molecular mass = Octane is an alkane. The table shows some properties of different alkanes. alkane formula melting point / °C boiling point / °C methane CH4 –182 –164 ethane C2H6 –183 –88 propane C3H8 –190 –42 butane C4H10 –138 pentane C5H12 –130 How does the boiling point of the alkanes change with the number of carbon atoms? Which alkane in the table is liquid at room temperature (20 °C)? Explain your answer. Draw the structure of methane showing all of the atoms and all of the bonds.
10. Chemistry of the environment  →  10.3. Air quality and climate
11. Organic chemistry  →  11.4. Alkanes
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4
Ammonia is manufactured by combining nitrogen and hydrogen at high temperature and pressure. N2 + 3H2 2NH3 What does the symbol mean? Ammonia is used to make fertilisers. Explain why farmers spread fertilisers on the soil where they are going to grow crops. Some fertilisers are salts made by adding acids to ammonia. Give the name of the compound formed when ammonia reacts with nitric acid. Farmers use calcium oxide to treat acidic soils. Explain how calcium oxide helps treat acidic soils. Suggest why farmers need to treat soils which are too acidic.
10. Chemistry of the environment  →  10.2. Fertilisers
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
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5
Lavandulol is a compound found in lavender flowers. The structure of lavandulol is shown. C C H CH3 CH3 CH2 CH2 CH2 CH3 C O H C H On the diagram, draw a circle around the alcohol functional group. How many carbon atoms are there in one molecule of lavandulol? What feature of the lavandulol structure shows that it is unsaturated? Describe a test to show that lavandulol is unsaturated. test result Lavandulol can be extracted from lavender flowers. The following statements are about the procedure for extracting lavandulol. A Stir the mixture and leave it for a few hours. B Filter off the solid from the solution. C Distil the solution. D Add solvent to the ground up lavender flowers. E Grind up the lavender flowers. Put the statements A, B, C, D and E in the correct order. The first one has been done for you. E Chromatography can be used to separate the coloured pigments extracted from lavender flowers. The apparatus used is shown. solvent chromatography jar cover chromatography paper baseline After a few minutes the solvent vapour fills the whole chromatography jar. Use the kinetic particle model to explain this. Three different dye mixtures, P, Q and R, were placed on a sheet of chromatography paper. Two pure dyes, X and Y, were also placed on the same piece of chromatography paper. The experiment was carried out and the results are shown. P Q R X Y Where were the dyes placed on the chromatography paper at the start of the experiment? Which dye mixture contained the greatest number of dyes? Which dye mixture contained both dye X and dye Y?
12. Experimental techniques and chemical analysis  →  12.3. Chromatography
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6
Chlorine and sodium hydroxide are manufactured by the electrolysis of concentrated aqueous sodium chloride. Chlorine is produced at the positive electrode . Name the substance produced at the negative electrode during the electrolysis. State the name of the particle that is removed from a chloride ion to make a chlorine atom. Complete the electronic structure of a chlorine molecule. Cl Cl Describe a test for chlorine. test result If chlorine reacts with sodium hydroxide, sodium chlorate(, NaOCl, is formed. Another compound of sodium is also produced. This forms a white precipitate on addition of aqueous silver nitrate. Complete the chemical equation for this reaction. Cl 2 + NaOH NaOCl + + H2O 1000 g of a solution produced by the electrolysis of concentrated aqueous sodium chloride contains the following masses of compounds. compound mass of substance present / g sodium chlorate(300 sodium chloride sodium hydroxide water total Calculate the mass of sodium hydroxide present in 200 g of this solution. All the water from the 1000 g of solution is evaporated. Deduce the mass of the remaining mixture.
4. Electrochemistry  →  4.1. Electrolysis
11. Organic chemistry  →  11.4. Alkanes
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7
Metals have characteristic properties. Write about the properties of metals. In your answer ● refer to the physical properties which are characteristic of metals, ● refer to the chemical properties which are characteristic of metals, ● include a word equation to show a chemical reaction of a metal. The table shows how easy it is to reduce four metal oxides. metal oxide ease of reduction calcium oxide not reduced by carbon at 1600 °C magnesium oxide reduced by carbon at 1600 °C nickel(oxide reduced by carbon at 350 °C zinc oxide reduced by carbon at 850 °C Use this information to put the metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive Uranium is a radioactive metal which has several isotopes. What is the meaning of the term isotopes? Give the main use of the isotope 235U.
9. Metals  →  9.1. Properties of metals
9. Metals  →  9.6. Extraction of metals
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