CAIE Chemistry (9701)

The melting points of some solids are shown in Table 1.1. Table 1.1 solid melting point / K magnesium 923 phosphorus 317 sodium chloride 1074 sulfur 392

(i) State the type of bonding present in magnesium and in sodium chloride. bonding in magnesium bonding in sodium chloride

Explain the difference in the melting points of magnesium and sodium chloride.

Explain the difference in the melting points of phosphorus and sulfur in terms of structure and bonding.

(i) Define electronegativity.

Explain why electronegativity increases across a period.

Name the strongest intermolecular force that exists between NH

molecules.

Draw a diagram to show the formation of the strongest intermolecular force between two molecules of NH

Include any relevant lone pairs of electrons and dipoles.

The melting points of ice and ammonia are shown in Table 1.2. Table 1.2 solid melting point / K ice 273 ammonia 195 Suggest two reasons for the difference in the melting points of ice and ammonia. [Total: 12]

Chlorine is a reactive element. It forms many compounds.

(i) Complete Table 2.1 to show the maximum oxidation number of the elements Na to P in their chlorides. Table 2.1 element Na Mg Al Si P maximum oxidation number

State what determines the maximum oxidation number of elements in Period 3.

An excess of cold water is added to the chloride of silicon.

Write an equation for the reaction between an excess of cold water and the chloride of silicon.

Suggest the pH of the solution produced in (b)(i).

An excess of cold water is added to the chloride of phosphorus.

Write an equation for the reaction between an excess of cold water and the chloride of phosphorus.

Suggest the pH of the solution produced in (c)(i).

(i) Write an equation for the reaction of chlorine with water.

Write an equation for the reaction of chlorine with hot NaOH(aq).

Bleach is used as a cleaning product to kill bacteria. It is made by adding compounds like sodium chlorate(I), NaCl O, to water.

Identify the formula of the ion present in bleach that kills bacteria.

Sodium chlorate(I), NaCl O, reacts with hydrogen peroxide to produce sodium chloride, water and oxygen gas. Construct an equation for this reaction.

A sample of bleach W contains an unknown concentration of sodium chlorate(I). 10.0 cm of W is diluted with distilled water to make a total volume of 100 cm bleach solution. 25.0 cm of this diluted bleach solution is added to an excess of hydrogen peroxide and the volume of gas produced measured under room conditions. The experiment is repeated and on average 25.0 cm of diluted bleach solution produces 42.0 cm of gas. Calculate the concentration, in g dm , of sodium chlorate(I) in W. concentration of NaCl O in W = g dm [3] [Total: 13]

Fig. 3.1 describes a sequence of reactions that can be used to produce a food additive, compound Y, from CH Cl . Cl CH CN CH COOH step 1 step 2 dilute acid step 3 Ca(s)

(i) State the reagent and conditions for step 1 in Fig. 3.1.

Give the systematic name of X.

Identify the type of reaction that occurs when dilute acid is added to X in step 2.

In step 3, Y and a gas are produced. Construct an equation for step 3.

CH COOH can also be formed from propan-1-ol and potassium dichromate(VI). State the conditions required. molecule of X. Table 3.1 type of bond number of bonds in X pi (π) [2] [Total: 8]

In industry, ethanol is made by reacting ethene with steam in the presence of H reaction 1 C

+ H O(g) OH(g)

Use the bond energy values in Table 4.1 to calculate the enthalpy change, ΔH , for reaction 1. Table 4.1 bond bond energy / kJ mol C-C 350 C=C 610 C-H 410 C-O 360 C=O 740 O-H 460 = kJ mol

Reaction 1 reaches equilibrium at constant temperature and pressure. Deduce what effect increasing the pressure will have on the amount of ethanol in the new equilibrium mixture. Use Le Chatelier's principle to explain your answer. effect of increasing pressure explanation

The mechanism for reaction 1 can be described in three steps. Steps 1 and 2 for reaction 1 are shown in Fig. 4.1. step 1 step 2 HO OH HO OH

Describe the behaviour of H in step 1 in Fig. 4.1. Explain your answer.

Identify the species that behaves as an electrophile in step 2 in Fig. 4.1. Explain your answer.

Complete Fig. 4.2 to show the mechanism for step 3 of reaction 1. Include charges, dipoles, lone pairs of electrons and curly arrows, as appropriate. HO OH HO OHH HCCH

Describe how a catalyst affects a reaction. Explain your answer.

Use Fig. 4.1 and Fig. 4.2 to justify why H is described as a catalyst in reaction 1.

Propene also reacts with steam. A mixture of organic products is produced. Explain why propan-2-ol is produced in the higher yield.

Describe the covalent bonds present between the carbon atoms in an ethene molecule by completing Table 4.2. Table 4.2 type of orbitals involved in bond how the orbitals overlap [2] [Total: 15]

Describe structural isomerism.

A and B are structural isomers with molecular formula C They are both straight-chained molecules with only one functional group. Table 5.1 describes observations when separate samples of A and B are added to different reagents. Table 5.1 reagent A B 2,4-dinitrophenylhydrazine (2,4-DNPH reagent) orange precipitate appearsorange precipitate appears Tollens' reagent silver mirror appears no reaction alkaline I

no reaction no reaction

Name the functional group present in both A and B.

Draw the structures of A and B in the boxes.

C is a structural isomer of A and B. C is straight chained and has two functional groups. C shows only one type of stereoisomerism. Table 5.2 describes observations when separate samples of C are added to different reagents. Table 5.2 reagent C 2,4-dinitrophenylhydrazine (2,4-DNPH reagent) no reaction

orange to colourless alkaline I

yellow precipitate appears

Draw the structure of C in the box.

Name the type of stereoisomerism shown by molecules of C.

D reacts in the presence of a sulfuric acid catalyst to form E and water. The structure of E is shown in Fig. 5.1.

Name the functional group present in E.

Identify the type of reaction that occurs when D reacts to form E.

Draw the structure of D in the box.

The infrared spectrum of E is shown in Fig. 5.2. 4000 3000 2000 1500 1000 500 transmittance / % wavenumber / cm 50100 Table 5.3 bondfunctional groups containing the bondcharacteristic infrared absorption range (in wavenumbers) / cm C-O hydroxy, ester 1040-1300 C=C aromatic compound, alkene 1500-1680 C=O amide carbonyl, carboxyl ester C-H alkane 2850-2950 N-H amine, amide 3300-3500 O-H carboxyl hydroxy Use Fig. 5.2 and Table 5.3 to predict two differences in the absorptions above 1500 cm of the infrared spectrum of D compared to E. Explain your answer. [Total: 12] Important values, constants and standards molar gas constant R = 8.31 J Kmol Faraday constant F = 9.65 × 10 C mol Avogadro constant L = 6.022 × 10mol electronic charge e = -1.60 × 10-19 molar volume of gas V = 22.4 dmmol at s.t.p. (101 kPa and 273 K) = 24.0 dmmol at room conditions ionic product of water K = 1.00 × 10-14mol (at 298 K (25 °C)) specific heat capacity of waterc = 4.18 kJ kg (4.18 J g To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Group The Periodic ble of Elements hydroge 1.0 He helium 4.0 34567893Li lithium 6.9 beryllium 9.0 atomic number atomic symbolKey name relative atomic mas sodiu 23.0 magnesium 24.319K potassium 39.1 calcium 40.1 rubidiu 85.5 38Sr strontium 87.6 caesiu 132.9 barium 137.3 87Fr francium Ra radium boron 10.813A aluminiu 27.0 galliu 69.749I indium 1 14.8 81T thallium 204.4 carbon 12.0 14Si silicon 28.1 germanium 72.6tin 18.7 82 lead 207.2 22Ti titanium 47.9 40Zr zirconium 91.2 72Hf hafniu 178.5 104 Rf rutherfordiu23V vanadium 50.9 niobiu 92.9 73Ta tantalum 180.9 105 Db dubnium 24Cr chromium 52.0 molybdenum 95.974W tungsten 183.8 106 Sg seaborgium manganes 54.9 43Tc technetium rheniu 186.2 107 Bh bohriu 26Fe iron 55.8 ruthenium 101.1 osmium 190.2 108 Hs hassium Co cobalt 58.9 rhodiu 102.977I iridiu 192.2 109 Mt meitnerium 28Ni nickel 58.7 palladiu 106.4 78Pt platinum 195.1 darmstadtium copper 63.5 Ag silver 107.9 gold 197.0 111 Rg roentgeniu zinc 65.4 cadmiu 12.4 80 mercury 200.6 coperniciu fleroviu livermorium nitrogen 14.015P phosphorus 31.0 33As arseni 74.9 antimony 121.8 83Bi bismuth 209.0 oxygen 16.016S sulfur 32.1 seleniu 79.0 52Te tellurium 127.6 polonium fluorine 19.017C chlorin 35.5 35Br bromin 79.953I iodine 126.9 85At Ne neon 20.2 18Ar argon 39.9 36Kr krypton 83.8 Xe xenon 131.3 Rn radon nihonium moscoviu tennessine oganesso 21Sc scandium 45.039Y yttrium 88.9 57-71 lanthanoids 89-103 actinoids 57La lanthanum 138.9 89Ac lanthanoids actinoids actinium Ce cerium 140.1 90Th thorium 232.0 59Pr praseodymium 140.9 protactinium 231.0 neodymium 144.492U uraniu 238.0 promethium neptuniu samarium 150.4 plutonium europium 152.0 americiu gadoliniu 157.3 Cm curium 65Tb terbium 158.9 97Bk berkeliu dysprosiu 162.5 98Cf californium holmiu 164.9 99Es einsteinium 68Er erbium 167.3 100 Fm fermium Tm thuliu 168.9 101 Md mendeleviu ytterbium 173.1 102 No nobeliu 71Lu lutetium 175.0 103 Lr lawrencium