0620_w07_qp_2
A paper of Chemistry, 0620
Questions:
7
Year:
2007
Paper:
2
Variant:
0
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1
Use Some oxides are listed below. calcium oxide carbon dioxide carbon monoxide phosphorus trioxide sodium oxide sulphur dioxide water Which one of these oxides is most likely to contribute to acid rain? Which one of these oxides is a product of the reaction between an acid and a carbonate? Which one of these oxides is formed by the incomplete combustion of carbon? Which one of these oxides is a good solvent? Which one of these oxides is used to neutralise acidic industrial waste products? Which two of these oxides reacts with water to form an alkaline solution? Complete the diagram to show the electronic structure of water. show hydrogen electrons by ‘o’ show oxygen electrons by ‘x’ H H O ×× ×× Examiner's Use The structure of phosphorus trioxide is shown below. P P O O P O P O O O Write the simplest formula for phosphorus trioxide.
7. Acids, bases and salts  →  7.2. Oxides
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
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2
Use The diagram shows a bottle of mineral water. top made of polylabel bottle made of polyThe polytop is made by polymerising propene molecules, CH3CH=CH2. Which one of the following best describes the propene molecules in this reaction? Put a ring around the correct answer. alkanes monomers polymers products salts State the name of the homologous series to which propene belongs. Propene is an unsaturated hydrocarbon. State the meaning of the following terms. unsaturated hydrocarbon Describe a chemical test to distinguish between an unsaturated hydrocarbon and a saturated hydrocarbon. State the results. test result with saturated hydrocarbon result with unsaturated hydrocarbon Examiner's Use The polybottle is made by polymerising ethene. nCH2=CH2 —CH2–CH2—n ( ) Complete the following sentence about this reaction by filling in the blank space. The formation of polyis an example of an polymerisation reaction. The label on the bottle lists the concentration of ions dissolved in the water in milligrams per litre. concentration of ions in milligrams per litre calcium nitrate chloride potassium 0.5 hydrogencarbonate sodium 4.5 magnesium sulphate State the name of two negative ions which appear in this list. Which metal ion in this list is present in the highest concentration? Calculate the amount of magnesium ions in 5 litres of this mineral water. Which ion in the list reacts with aqueous silver nitrate to give a white precipitate? Which ion in the list gives off ammonia when warmed with sodium hydroxide and aluminium foil? Complete the equation to show the formation of a potassium ion from a potassium atom. K → K+ + Examiner's Use The pH of the mineral water is 7.8. Which one of the following best describes this pH? Tick one box. slightly acidic slightly alkaline neutral very acidic very alkaline Pure water can be obtained by distilling the mineral water using the apparatus shown below. heat flask mineral water beaker A State the name of the piece of apparatus labelled A. Where does the pure water collect? How does the boiling point of the mineral water in the flask compare with the boiling point of pure water? Examiner's Use The diagram shows how mineral water is formed. Mineral water contains no bacteria or particles of earth. water drains through limestone mineral water surface water soil and bacteria water bacteria and soil particles limestone particles Use the diagram to explain how the water is purified from bacteria and particles of earth.
9. Metals  →  9.4. Reactivity series
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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3
Use This question is about metals. Match up the metals in the boxes on the left with the descriptions in the boxes on the right. The first one has been done for you. silver aluminium potassium platinum iron a metal used to make aircraft bodies a metal used in jewellery a metal extracted from haematite a very soft metal an unreactive metal used for electrodes Iron powder reacts rapidly with sulphuric acid to form aqueous iron(sulphate and hydrogen. Fe+ H2SO4→ FeSO4+ H2Describe two things that you would see happening as this reaction takes place. Alloys are often more useful than pure metals. Complete the following sentences by filling in the blank spaces. An alloy is a of a metal with other elements. The properties of can be changed by the controlled use of additives to form steel alloys. Increasing the amount of carbon in a steel makes it Name one other alloy apart from steel. Iron rusts very easily. Describe two methods of preventing rusting. 1. 2.
9. Metals  →  9.3. Alloys and their properties
9. Metals  →  9.2. Uses of metals
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4
Use The diagram shows the changes in pH in a student’s mouth after she has eaten a sweet. time / minutes pH Describe how the acidity in the student’s mouth changes after she has eaten the sweet. Chewing a sweet stimulates the formation of saliva. Saliva is slightly alkaline. Use this information to explain the shape of the graph. State the name of the type of reaction which occurs when an acid reacts with an alkali. Many sweets contain citric acid. The formula of citric acid is shown below. HO C CH2 CH2 CO2H CO2H CO2H Put a ring around the alcohol functional group on the above formula. State the name of the – CO2H functional group in citric acid. Ethanoic acid also has a – CO2H functional group. Write down the formula for ethanoic acid. Examiner's Use Citric acid can be extracted from lemon juice as follows: stage 1: add calcium carbonate to hot lemon juice stage 2: filter off the precipitate which is formed (calcium citrate) stage 3: wash the calcium citrate precipitate with water stage 4: add sulphuric acid to the calcium citrate to make a solution of citric acid stage 5: crystallise the citric acid When calcium carbonate is added to lemon juice a fizzing is observed. Explain why there is a fizzing. Draw a diagram to show step 2. Label your diagram. Suggest why the calcium citrate precipitate is washed with water. Describe how you would carry out step 5. Nowadays, citric acid is usually made by the fermentation of sugars. Which one of the following is required for fermentation? Put a ring around the correct answer. acid high temperature light microorganisms nitrogen
11. Organic chemistry  →  11.7. Carboxylic acids
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
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5
Use Some coal dust was heated with copper(oxide using the apparatus shown below. heat coal dust and copper(oxide plug of damp cotton wool Coal contains carbon and various hydrocarbons. The carbon reduces the copper(oxide when heated. What do you understand by the term reduction? At the end of the experiment a reddish-brown solid remained in the tube. State the name of this reddish-brown solid. The reddish brown solid conducts electricity. How could you show that it conducts electricity? During the experiment, water collected on the cooler parts of the test tube. Suggest where the hydrogen in the water comes from. Water is a liquid. Describe the arrangement and motion of the particles in a liquid.
4. Electrochemistry  →  4.1. Electrolysis
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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6
Use The table below shows an early form of the Periodic Table made by John Newlands in 1866. H F Cl Co, Ni Br Li Na K Cu Rb Be Mg Ca Zn Sr B Al Cr Y C Si Ti In N P Mn As O S Fe Sc Newlands arranged the elements according to their relative atomic masses. What governs the order of the elements in the modern Periodic Table? Use your modern Periodic Table to suggest why Newlands put cobalt and nickel in the same place. Which group of elements is missing from Newlands’ table? Describe three other differences between Newlands’ table and the modern Periodic Table. You must not give any of the answers you mentioned in parts , or . Examiner's Use Carbon exists in two forms, graphite and diamond. strong bonds weak forces diamond graphite = carbon atom Use ideas about structure and bonding to suggest why graphite is used as a lubricant, why diamond is very hard.
8. The Periodic Table  →  8.1. Arrangement of elements
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7
Examiner's Use Compounds and elements vary in their volatility, solubility in water and electrical conductivity depending on their bonding. Place copper, methane and water in order of their volatility. most volatile → least volatile → Complete the table to show the solubility in water and electrical conductivity of various solids. solid structure soluble or insoluble does it conduct electricity? silver metallic insoluble sodium chloride ionic no sulphur covalent no copper sulphate ionic soluble The apparatus shown below is used to electrolyse concentrated aqueous sodium chloride. + – electrode A electrode B concentrated aqueous sodium chloride Suggest a suitable substance which could be used for the electrodes. State the name of the gas given off at electrode A, at electrode B. Examiner's Use State the name given to electrode A. Explain why aqueous sodium chloride conducts electricity but solid sodium chloride does not.
2. Atoms, elements and compounds  →  2.4. Ions and ionic bonds
4. Electrochemistry  →  4.1. Electrolysis
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