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CIE Jun 2014 v3 Paper 4 Q1
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![Section A Answer all the questions in the spaces provided. (a) (i) State how the melting point and density of iron compare to those of calcium. PMT melting point of iron:density of iron:(ii) Explain why these differences occur. melting point:density:[4] (b) The following diagram shows the apparatus used to measure the standard electrode potential, o, of a cell composed of a Cu(II) / Cu electrode and an Fe(II) / Fe electrode. (i) Finish the diagram by adding components to show the complete circuit. Label the components you add. (ii) In the spaces below, identify or describe what the four letters A-D represent. ABCDUCLES 2014 9701/43/M/J/14<br />
PMT (iii) Use the Data Booklet to calculate the E o for this cell.(iv) Predict how the size of the overall cell potential would change, if at all, as the concentration of solution C is increased. Explain your reasoning.[8] (c) The iron(II) complex ferrous bisglycinate hydrochloride is sometimes prescribed, in capsule form, to treat iron de ciency or anaemia. A capsule containing 500 mg of this iron(II) complex was dissolved in dilute H2SO4 and titrated with 0.0200 mol dm3 KMnO4. 18.1 cm3 of KMnO4 solution were required to reach the end point. The equation for the titration reaction is as follows. 5Fe2+ + MnO4+ 8H+5Fe3+ + Mn2+ + 4H2O (i) Describe how you would recognise the end point of this titration.(ii) Calculate the number of moles of Fe2+ in the capsule, the mass of iron in the capsule, the molar mass of the iron(II) complex, assuming 1 mol of the complex contains 1 mol of iron.UCLES 2014 9701/43/M/J/14 [4] [Total: 16] [Turn over<br />](https://learnah.org/wp-content/uploads/2018/08/June_2014_v3_QP_-_Paper_4_CIE_Chemistry_A-level_1-0.jpg)
![Page 2 Mark Scheme Syllabus Paper GCE A LEVELMay/June 2014 9701 43 Section A (a) (i) m. pt. is high(er) / large(r) / greater (for iron) density is high(er) / large(r) / greater (for iron) (ii) (higher m. pt. due to) strong attraction between cations and electrons or more delocalised electrons (higher density due to) greater Ar and smaller radius [Total: 16] (a) (i) A complex is a compound / molecule / species / ion formed by a central metal atom / ion surrounded by / bonded to one or more ligands / groups/ molecules / anions A ligand is a species that contains a lone pair of electrons that forms a dative bond to a metal atom / ion / or a lone pair donor to metal atom / ionCambridge International Examinations 2014 PMT [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] [1] (b) (i) components to be added: voltmeter or V salt bridge [must be labelled] (ii) M1: A and B copper (metal) or Cu and iron (metal) or Fe M2: either C or D as 1 mol dm 3 / 1 M M3 C and D Cu or CuSO4 or CuCl 2 or Cu (NO3)2 etc. and 2+ 2+ Fe or FeSO4 etc. (iii) E cell = 0.34 + 0.44 = 0.78 (V) 2+ (iv) if C is Fe ; (as [C] increases), the E of the Fe 2+ / Fe increases / becomes more positive / less negative [1] so the overall cell potential / Ecell would decrease / become less positive / more negative or 2+ if C is Cu ; (as [C] increases), the E of the Cu positive / less negative 2+ /Cu increases / becomes more so the overall cell potential / Ecell would increase / become more positive / less negative (c) (i) (colour change is) colourless to pink/pale purple or (end point is the first) permanent (pale) pink/pale purple colour (ii) {n(MnO4 ) = 0.0218.1/1000 = 3.6210 mol} n(Fe ) = 5n(MnO4 ) = 1.8110 2+ 3 -4 mol mass of Fe = 55.8 x 1.8110 3 = 0.101 g (M255.8) ecf Mr = mass / moles = 0.500/1.8110 3 = 276.2 ecf<br />](https://learnah.org/wp-content/uploads/2018/08/June_2014_v3_MS_-_Paper_4_CIE_Chemistry_A-level_1.jpg)