0620_s19_qp_42
A paper of Chemistry, 0620
Questions:
7
Year:
2019
Paper:
4
Variant:
2
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1
The names of eight substances are given. aluminium oxide calcium oxide ethanol nitrogen iron(oxide methane oxygen silicon(oxide Answer the following questions about these substances. Each substance may be used once, more than once or not at all. State which substance is: the main constituent of natural gas a reactant in respiration the main constituent of bauxite a product of photosynthesis a greenhouse gas a macromolecular solid. 
11. Organic chemistry  →  11.3. Fuels
10. Chemistry of the environment  →  10.1. Water
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22Na , 23Na and 24Na are isotopes of sodium. Describe how these sodium isotopes are the same and how they are different in terms of the total number of protons, neutrons and electrons in each. same different  Why do all three isotopes have an overall charge of zero? Why do all three isotopes have the same chemical properties? Why do sodium ions have a charge of +1? Carbon is an element which exists in different forms. Name two forms of the element carbon that have giant covalent structures. and Name the oxide of carbon that is a toxic gas. 
2. Atoms, elements and compounds  →  2.3. Isotopes
8. The Periodic Table  →  8.1. Arrangement of elements
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This question is about phosphorus and compounds of phosphorus. Phosphorus has the formula P4. Some properties of P4 are shown. melting point / °C boiling point / °C electrical conductivity non-conductor solubility in water insoluble Name the type of bonding that exists between the atoms in a P4 molecule. Explain, in terms of attractive forces between particles, why P4 has a low melting point. Explain why phosphorus is a non-conductor of electricity. Phosphorus, P4, reacts with air to produce phosphorus(oxide, P4O10. Write a chemical equation for this reaction. What type of chemical reaction is this? Phosphorus(oxide, P4O10, is an acidic oxide. Phosphorus(oxide, P4O10, reacts with aqueous sodiumhydroxide to form a salt containing the phosphate ion, PO4 3–. Water is the only other product. Write a chemical equation for the reaction between phosphorus(oxide and aqueous sodiumhydroxide. Phosphine has the formula PH3. Complete the dot-and-cross diagram to show the electron arrangement in a molecule of phosphine. Show outer shell electrons only. P H H H  Phosphine, PH3, has a similar chemical structure to ammonia, NH3. Ammonia acts as a base when it reacts with sulfuric acid. What is meant by the term base? Write a chemical equation for the reaction between ammonia and sulfuricacid. 
2. Atoms, elements and compounds  →  2.5. Simple molecules and covalent bonds
7. Acids, bases and salts  →  7.1. The characteristic properties of acids and bases
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4
Methanol is made industrially by reacting carbonmonoxide with hydrogen. The gases react at a temperature of 250 °C and a pressure of 75atmospheres. CO+ 2H2CH3OHThe forward reaction is exothermic. Suggest a source of hydrogen for this industrial process. Complete the table using only the words increases, decreases or no change. effect on the rate of the reverse reaction effect on the equilibrium yield of CH3OHadding a catalyst no change increasing the temperature increases decreasing the pressure  Methanol is a member of the homologous series of alcohols. State two general characteristics of a homologous series.  Draw the structures of two different alcohols, each containing three carbon atoms. Show all of the atoms and all of the bonds. Name these two alcohols. name name  What term is used to describe compounds with the same molecular formula but different structural formulae? Alcohols react with carboxylic acids to produce esters. The structure of ester X is shown. C O O H C H H C H H H Name ester X. Give the name of the carboxylic acid and the alcohol that react together to produce esterX. carboxylic acid alcohol  EsterY is different from esterX but also has the formula C3H6O2. Draw the structure of esterY. Show all of the atoms and all of the bonds.  
11. Organic chemistry  →  11.2. Naming organic compounds
11. Organic chemistry  →  11.1. Formulae, functional groups and terminology
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Copper(sulfate crystals, CuSO4.5H2O, are hydrated. Copper(sulfate crystals are made by reacting copper(carbonate with dilute sulfuricacid. The equation for the overall process is shown. CuCO3 + H2SO4 + 4H2O CuSO4.5H2O + CO2 step 1 Powdered solid copper(carbonate is added to 50.0 cm3 of 0.05 mol / dm3 sulfuricacid until the copper(carbonate is in excess. step 2 The excess of copper(carbonate is separated from the aqueous copper(sulfate. step 3 The aqueous copper(sulfate is heated until the solution is saturated. step 4 The solution is allowed to cool and crystallise. step 5 The crystals are removed and dried. Calculate the maximum mass of the copper(sulfate crystals, CuSO4.5H2O, that can form using the following steps. ● ● Calculate the number of moles of H2SO4 in 50.0 cm3 of 0.05 mol / dm3 H2SO4.  mol ● ● Determine the number of moles of CuSO4.5H2O that can form.  mol ● ● The Mr of CuSO4.5H2O is 250. Calculate the maximum mass of CuSO4.5H2O that can form.  g  Steps 1–5 were done correctly but the mass of crystals obtained was less than the maximum mass. Explain why. State two observations that would indicate that the copper(carbonate is in excess in step1.  When the reaction in step1 is done using lumps of copper(carbonate instead of powder, the rate of reaction decreases. All other conditions are kept the same. Give a reason for this. Explain your answer in terms of particles. Name a different substance, other than copper(carbonate, that could be added to dilute sulfuricacid to produce copper(sulfate in step1. Name the process used to separate the aqueous copper(sulfate from the excess of copper(carbonate in step2. The solution of aqueous copper(sulfate was heated until it was saturated in step3. Suggest what is meant by the term saturated solution. What evidence would show that the solution was saturated in step3? Why should the aqueous copper(sulfate not be heated to dryness in step3? 
4. Electrochemistry  →  4.1. Electrolysis
6. Chemical reactions  →  6.3. Reversible reactions and equilibrium
9. Metals  →  9.4. Reactivity series
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The halogens are the elements in GroupVII of the Periodic Table. Predict the physical state and colour of astatine at room temperature and pressure. physical state colour  When chlorine reacts with aqueous potassiumbromide a displacement reaction occurs. Describe the colour change of the solution. from to  Write a chemical equation for this reaction. Reactions occur when some aqueous solutions of halogens are added to aqueous solutions of halides. Use the key to complete the table to show the results of adding halogens to halides. key = reaction = no reaction halides KCl KBrKIhalogens Cl 2 Br2I2 
8. The Periodic Table  →  8.3. Group VII properties
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Displacement reactions occur between metals and metal ions. Displacement reactions can be used to determine the order of reactivity of metals such as lead (Pb), nickel (N, and silver (Ag). The ionic equation for a displacement reaction is shown. Ni+ Pb2+Pb+ Ni2+The ionic half-equations for this reaction are shown. NiNi2++ 2e– Pb2++ 2e– PbThe ionic half-equations show that electrons are donated by nickel atoms and accepted by lead ions. Identify the reducing agent in the displacement reaction. Give a reason for your answer. reducing agent reason  What is the general term given to the type of reaction in which electrons are transferred from one species to another? The ionic equation for another displacement reaction is shown. Pb+ 2Ag+2Ag+ Pb2+Write the two ionic half-equations for this reaction.  Use the information in and to put the three metals lead, nickel and silver in order of reactivity. most reactive least reactive  Nickel is a transition element. Nickel is stronger than sodium. Describe two other differences in the physical properties of nickel and sodium.  Predict one difference in the appearance of aqueous solutions of nickel compounds compared to aqueous solutions of sodium compounds. Copper is refined by electrolysis. Nickel can be refined using a similar method. The diagram shows the refining of nickel by electrolysis. Complete the labels in the boxes. power supply + – cathode made of electrolyte of anode made of  Indicate, by writing N on the diagram, where nickel is produced. 
4. Electrochemistry  →  4.1. Electrolysis
9. Metals  →  9.4. Reactivity series
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