0620_s20_qp_32
A paper of Chemistry, 0620
Questions:
8
Year:
2020
Paper:
3
Variant:
2
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1
A list of symbols and formulae is shown. CH4 Cl – CO2 Cr3+ Cu2+ Fe2+ H2 K+ N2 O2 SO2 Answer the following questions about these symbols and formulae. Each symbol or formula may be used once, more than once or not at all. Which symbol or formula represents: a compound produced by the thermal decomposition of calcium carbonate an element which is used as a fuel a gas which forms 78% of clean dry air an ion which forms a blue precipitate when added to aqueous sodiumhydroxide an ion formed when an atom gains an electron? Complete the table to show the relative charge and approximate relative mass of a proton, a neutron and an electron. type of particle relative charge approximate relative mass proton neutron electron –1  Deduce the number of electrons and neutrons in an atom of the isotope of potassium shown. 41K number of electrons number of neutrons  
2. Atoms, elements and compounds  →  2.2. Atomic structure and the Periodic Table
3. Stoichiometry  →  3.2. Relative masses of atoms and molecules
3. Stoichiometry  →  3.1. Formulae
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2
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 Al 3+ 0.2 NH4 + 22.0 calcium Ca2+ 0.2 iron(Fe2+ 79.0 magnesium Mg2+ 0.1 nitrate NO3 – 28.0 phosphate PO4 3– 14.0 potassium K+ 39.0 SO4 2– 5.1 Answer these questions using the information in the table. Which negative ion has the lowest concentration? State the name of the SO4 2– ion. Calculate the mass of nitrate ions in 200 cm3 of this solution.  mass = mg Name the compound that contains NH4 + ions and NO3 – ions. Describe a chemical test for calcium ions. test observations  The names and formulae for some compounds are shown. aluminium nitrate, Al (NO3)3 magnesium nitrate, Mg(NO3)2 sodium nitrate, NaNO3 Deduce the formula for calcium nitrate. 
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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3
Many compounds have important uses. Complete the table to show the name, number of atoms in the formula and use. name of compound number of atoms in the formula formula use water hydrogen = 2 oxygen = 1 H2O sulfur = 1 oxygen = 2 SO2 calcium hydroxide (slaked lime) calcium = oxygen = hydrogen = Ca(OH)2  The table compares the reactions of four metals with steam. metal reaction with steam copper does not react magnesium reacts rapidly sodium reacts explosively zinc reacts slowly when warmed Put the four metals in order of their reactivity. Put the least reactive metal first. least reactive most reactive  Sodium reacts with molten sodiumhydroxide. Complete the chemical equation for this reaction. 2Na + NaOH → Na2O + H2 
9. Metals  →  9.4. Reactivity series
9. Metals  →  9.1. Properties of metals
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4
The properties of the first four GroupI elements are shown in the table. element density in g / cm3 melting point / °C boiling point / °C lithium 0.53 sodium 0.97 potassium 0.86 rubidium Answer these questions using only the information in the table. Describe the general trend in the boiling points of the GroupI elements. Explain why it is difficult to predict the density of rubidium. Deduce the state of rubidium at 45 °C. Explain your answer.  When sodium reacts with carboxylic acids, hydrogen is produced. Describe a test for hydrogen. test observations  The structure of a carboxylic acid is shown. C O H C H H C H H C H H C H H H O Deduce the formula of this carboxylic acid to show the number of atoms of carbon, hydrogen and oxygen. Universal indicator is added to an aqueous solution of sodium oxide. ● ● What colour change is observed? from green to ● ● Give a reason for your answer.  
8. The Periodic Table  →  8.2. Group I properties
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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5
Molten magnesiumbromide is electrolysed. The incomplete apparatus is shown. + – Complete the diagram by: ● ● labelling the anode and cathode ● ● adding the power supply and connecting wires.  Predict the products of this electrolysis at the: positive electrode negative electrode.  The electrodes must be able to conduct electricity. Give one other property that the electrodes must have. Name a suitable element that can be used as an electrode. Aqueous chlorine reacts with aqueous magnesiumbromide. Cl 2 + MgBr2 → Br2 + MgCl 2 How does this reaction show that chlorine is more reactive than bromine? What colour is bromine in aqueous solution? Complete the chemical equation for the reaction of chlorine with phosphorus. Cl 2 + 2P → PCl 5 
4. Electrochemistry  →  4.1. Electrolysis
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6
Acids have characteristic properties. Hydrochloric acid reacts with magnesiumcarbonate. Name the products of this reaction and give the observations. The rate of reaction of iron with sulfuricacid can be determined by measuring the time taken to produce 20 cm3 of hydrogen. A student measured the time taken to produce 20 cm3 of hydrogen using three different concentrations of sulfuricacid. In each experiment the student used: ● ● 1 g of iron powder ● ● the same temperature ● ● the same volume of sulfuric acid. The results are shown in the table. concentration of acid in mol / dm3 time / s 0.1 0.2 0.5 Use the information in the table to describe how the rate of reaction changes with the concentration of sulfuricacid. Describe the effect of each of the following on the rate of this reaction with 0.5 mol / dm3 of sulfuricacid. ● ● Larger pieces of iron are used. All other conditions stay the same. ● ● The temperature is increased. All other conditions stay the same.  Heat is given out when iron reacts with sulfuricacid. What term describes a reaction which gives out heat? The reaction of iron with steam is shown. 3Fe + 4H2O → Fe3O4 + 4H2 How does this equation show that iron gets oxidised? Rust contains hydrated iron(oxide. Describe and explain one method of preventing iron from rusting. 
6. Chemical reactions  →  6.2. Rate of reaction
9. Metals  →  9.4. Reactivity series
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7
The structure of nerol is shown. C C H H H C C H H H H C C H H H H H C C C H H O H C H H H Draw a circle around the alcohol functional group on the structure of nerol. What feature of the nerol molecule shows that it is an unsaturated compound? Nerol can be extracted from some plants. Crushed plant leaves containing nerol are mixed with an organic solvent called octane. Nerol dissolves in octane. Describe how you would separate the crushed plant leaves from the solution of nerol in octane. The boiling point of nerol is 224 °C. The boiling point of octane is 126 °C. Explain how distillation separates nerol from the octane. The mixture of coloured compounds in plant leaves can be separated by chromatography. The apparatus is shown. chromatography paper lid On the diagram: ● ● draw an ‘X’ to show where the mixture of coloured compounds is placed at the start of the experiment ● ● draw a line to show the level of the solvent at the start of the experiment.  Ethanol is a solvent. Draw the structure of ethanol to show all of the atoms and all of the bonds.  Complete the sentences about the manufacture of ethanol using words from the list. catalyst hydrocarbon hydrogen oxygen plastic steam Ethanol is manufactured by the reaction of ethene with . The rate of this reaction is increased by the use of a .  Ethene and propene are in the same homologous series of organic compounds. Which two statements about ethene and propene are correct. Tick two boxes. They have the same physical properties. They have the same number of carbon atoms. They have similar chemical properties. They have the same number of hydrogen atoms. They have the same functional group.  
11. Organic chemistry  →  11.6. Alcohols
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8
The diagram shows part of the structures of caesiumchloride and carbondioxide. caesium chloride carbon dioxide Cl – Cs+ Cl – Cs+ Cl – Cs+ Cl – Cs+ Cl – Cs+ Cl – Cs+ O C O O C O O C O O C O Describe both caesiumchloride and carbondioxide in terms of: ● ● bonding ● ● solubility in water ● ● arrangement of particles.  Caesiumoxide is a compound. What is meant by the term compound ? Explain why caesium is not extracted from caesiumoxide by heating with carbon. Caesium is a metal. Describe two properties that are characteristic of most metals.  Carbondioxide is a gas. Which one of these processes does not produce carbondioxide? Tick one box. the reaction of hydrochloric acid with calcium carbonate respiration in animals and plants the reaction of hydrochloricacid with magnesium the thermal decomposition of calciumcarbonate  Carbondioxide is a greenhouse gas. Give one effect of an increase in the concentration of greenhouse gases in the atmosphere. 
9. Metals  →  9.4. Reactivity series
10. Chemistry of the environment  →  10.3. Air quality and climate
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
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