9701_w18_qp_22
A paper of Chemistry, 9701
Questions:
4
Year:
2018
Paper:
2
Variant:
2
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1
The model of the nuclear atom was first proposed by Ernest Rutherford. He developed this model on the basis of results obtained from an experiment using gold metal foil. Complete the table with information for two of the particles in an atom of 197Au. particle relative mass relative charge location within atom total number in an atom of 197Au electron 0.0005 –1 neutron nucleus  State the type of bonding in gold. A sample of gold found in the earth consists of only one isotope. Explain what is meant by the term isotopes. A different sample of gold contains more than one isotope. Suggest why this different sample of gold has the same chemical properties as the sample found in the earth. Tumbaga is an alloy of copper and gold. A sample of tumbaga was analysed. The mass spectrum of the sample is shown. 63 65 56.36 25.14 m / e percentage abundance x Calculate the percentage abundance of gold, x, in the sample of tumbaga.  x = % Calculate the relative atomic mass, Ar , of the copper present in this sample. Give your answer to two decimal places.  Ar (Cu) = 
1. Atomic structure  →  1.1. Particles in the atom and atomic radius
22. Analytical techniques  →  22.2. Mass spectrometry
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2
The table gives some data for elements in the third period and some of their compounds. element Na Mg Al Si P S type of bonding metallic covalent covalent formula of oxide P4O10 SO2 formula of chloride NaCl MgCl 2 SCl 2 Complete the table to show the bonding in the elements, and the formulae of their oxides and chlorides. SCl 2 is formed in the following reaction. S2Cl 2+ Cl 22SCl 2ΔH = – 40.6 kJ mol–1 Complete the ‘dot-and-cross’ diagram to show the bonding in a molecule of SCl 2. Show outer electrons only.  Complete and fully label the reaction pathway diagram for the reaction between S2Cl 2 and Cl 2. Include labels for activation energy, Ea, and enthalpy change of the forward reaction, ΔH. energy progress of reaction S2Cl 2+ Cl 2 On the axes, sketch the trend in melting point of the elements Na to S. melting point of element Na Mg Al Si P S  Give three statements to explain your sketch.  Write an equation for the reaction of P4O10 with water. SO2 can be released into the atmosphere when fossil fuels containing sulfur are burnt. State and explain one environmental consequence of the release of SO2 into the atmosphere. The elements in the third period show a general increase in their first ionisation energies from left to right. Identify two pairs of successive elements in the third period that do not agree with this statement. For each pair, explain why the change in ionisation energy does not agree with this statement. Use of the Data Booklet may help you to answer this question. pair 1 explanation pair 2 explanation  
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
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Trihalomethanes are organic molecules in which three of the hydrogen atoms of methane are replaced by halogen atoms, for example CHF3. The equation shows a reaction to produce CHF3. CHI3+ 3AgFCHF3+ 3AgIUse the data to calculate the enthalpy change of reaction, ΔHr , for this formation of CHF3. compound enthalpy change of formation, ΔHf / kJ mol–1 CHI3–182.1 CHF3– 692.9 AgF–204.6 AgI– 61.8  enthalpy change of reaction, ΔHr = kJ mol–1 The graph shows the relationship between pV and p at a given temperature for CHF3 and an ideal gas. pV p / atm CHF3 ideal gas CHF3 is not an ideal gas. State three basic assumptions that scientists make about the properties of ideal gases.  Explain why CHF3 deviates from the properties of an ideal gas at pressures greater than 300 atm. A different trihalomethane, CHCl 3, reacts with O2 to produce carbonyldichloride. HCl is also released as a product of this reaction. C carbonyl dichloride Cl Cl O Write an equation for this reaction of CHCl 3 with O2. The conversion of CHCl 3 to carbonyldichloride can be monitored by infra-red spectroscopy. The infra-red spectrum of carbonyldichloride is shown. transmittance wavenumber / cm–1 On the infra-red spectrum of carbonyldichloride identify with an X the absorption that would not be present in an infra-red spectrum of CHCl 3. Explain your answer.  Suggest another difference between the infra-red spectra of CHCl 3 and carbonyldichloride. 
4. States of matter  →  4.1. The gaseous state: ideal and real gases and \( pV = nRT \)
11. Group 17  →  11.2. The chemical properties of the halogen elements and the hydrogen halides
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4
The diagram shows a reaction sequence starting from ethanal. C P ethanal H3C H3C CO2H CO2H OH C C C R Q H H H O C S H3C O H CO2H HCN and NaCN reaction 1 H2SO4reaction 2 reaction 3 reaction 4 H Draw the displayed formula of P.  Name the type of chemical reaction that occurs in reaction3. Write an equation to represent reaction4. Use [O] to represent the oxidising agent. State the reagents and conditions for reaction4. CompoundQ is formed as a mixture of two optical isomers. Explain what is meant by the term optical isomers. Draw the two optical isomers of Q, showing clearly their three‑dimensional structures.  R can be used to make a polymer, W, in two steps. R W addition polymerisation intermediate polymer NaOHDraw one repeat unit of W.  Compound Z, H2C=CHCH3, is produced from R. Z can be used in a two-step process to produce 2-aminopropane. In the first step, Z reacts with HBr to form two products. The structure of the product depends on which intermediate is formed, intermediateI or intermediateII. intermediate I CH3 C H3C H + intermediate II CH3 C H H H H C + Explain why intermediateI is more likely to form than intermediateII. When intermediateI forms, the product of the first step is T. Complete the diagram to show the mechanism for the conversion of Z to T. Include all relevant charges, partial charges, curly arrows and lone pairs. C C H H H Br H CH3 CH3 C H3C H + H3C Br H C T Z CH3  T can then be converted to 2-aminopropane. NH3 ethanol H3C Br H C T CH3 H3C NH2 H C 2-aminopropane CH3 Name the mechanism for this conversion. Compound S, CH3COCO2H, can be reduced by LiAl H4. Complete the equation using structural formulae to represent this reaction. Use [H] to represent the reducing agent. CH3COCO2H + Other reducing agents containing Group1 metal cations include LiBH4, NaBH4 and KBH4. The strength of the reducing agent depends on the size of its cation. Give the electronic configuration of the Na+ cation. 1s2 Suggest why ionic radius increases down Group1. 
14. Hydrocarbons  →  14.2. Alkenes
14. Hydrocarbons  →  14.1. Alkanes
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