Zadanie 1a
Determine the coefficients needed to balance the equation for the reaction between sodium and water. Na(s) + H2O(l) → NaOH(aq) + H2(g)
Chemistry HL Paper 2, May 2022, TZ2
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Dodaj cały arkusz do zestawuZadanie 1b
A 0.460 g piece of sodium was placed in 250.0 cm3 of water. (i) Calculate the molar concentration of the sodium hydroxide solution formed. Assume that the volume of the solution is 250.0 cm3. (ii) Calculate the volume of hydrogen gas…
Zadanie 1c
Identify the oxidizing agent in the reaction of sodium with water and justify your answer in terms of oxidation states.
Zadanie 1d
Describe two observations, other than the formation of gas bubbles, that would show that the reaction of sodium with water is exothermic.
Zadanie 2a
Explain why the first ionization energy of magnesium is greater than that of sodium.
Zadanie 2b
The diagram represents the electron energy levels in a hydrogen atom. (i) Suggest two features of the behaviour of electrons in atoms that this energy level model cannot explain or represent. (ii) Draw an arrow, labelled X, on the diagram to represent the…
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Zadanie 3a
(i) Silver ions oxidize copper metal. 2 Ag+(aq) + Cu(s) → 2 Ag(s) + Cu2+(aq) Calculate the standard cell potential, Ecell⊖, in V, for this reaction. Use section 19 of the data booklet. (ii) Determine, giving a reason, whether lead(II)…
Zadanie 3b
Molten lead(II) bromide undergoes electrolysis in an electrolytic cell at 420 °C, using inert electrodes. (i) Deduce the half-equation for the reaction at each electrode. Cathode (negative electrode): Anode (positive electrode): (ii) Deduce the…
Zadanie 4a
The reaction between nitrogen dioxide and carbon monoxide was studied at 600 K. NO2(g) + CO(g) → NO(g) + CO2(g) The following experimental data were obtained. (i) Deduce the order of reaction with respect to nitrogen dioxide. (ii) Deduce the rate…
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Zadanie 4b
Two conditions must both be met for a collision between an NO2 molecule and a CO molecule to result in a reaction. State these two conditions.
Zadanie 4c
Nitrogen dioxide is in equilibrium with colourless dinitrogen tetroxide in the gas phase. N2O4(g) ⇌ 2 NO2(g) State the expression for the equilibrium constant, Kc, of this equilibrium.
Zadanie 4d
Consider the formation of gaseous nitrogen dioxide from liquid dinitrogen tetroxide. N2O4(l) → 2 NO2(g) ΔH⊖ = +85.9 kJ mol−1 (i) Calculate the entropy change of the reaction, ΔS⊖, in…
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Zadanie 5a
(i) State the full electron configuration of Co2+. (ii) Explain why there is a large increase from the 9th to the 10th ionization energy of cobalt.
Zadanie 5b
Calculate the oxidation state of sulfur in cobalt(II) disulfide, CoS2.
Zadanie 5c
Describe the bonding in solid cobalt, Co(s).
Zadanie 6a
Outline how the presence of the silver catalyst affects the rate of the reaction, and explain why.
Zadanie 6b
(i) On the axes below, sketch Maxwell–Boltzmann energy distribution curves for the methanol molecules at two temperatures, T1 and T2, where T2 > T1. (ii) Explain the effect of increasing the temperature on the equilibrium yield of methanal.
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Zadanie 6c
(i) Draw the Lewis formula of methanal. (ii) Explain the electron domain geometry around the carbon atom in methanal.
Zadanie 6d
(i) Methanal can be reduced. State the name of the organic product formed. (ii) Methanal can also be oxidized to methanoic acid, HCOOH, which is a weak Brønsted–Lowry acid. State the meaning of the term weak Brønsted–Lowry acid.
Zadanie 7a
(i) State why ammonia can act as a Lewis base. (ii) Calculate the pH of a 2.50 × 10−2 mol dm−3 aqueous solution of ammonia. pKb = 4.75 at 298 K. (iii) Justify whether a 1.0 dm3 solution made by mixing 0.30 mol NH3…
Zadanie 7b
(i) Sketch the shape of a sigma (σ) bond and of a pi (π) bond, showing the overlapping orbitals. Sigma (σ): Pi (π): (ii) Identify the number of sigma bonds and the number of pi bonds in one molecule of acrylonitrile. Sigma (σ): Pi (π): (iii) State the…
Zadanie 7c
Acrylonitrile and but-1-ene have similar relative molecular masses but very different boiling points. Suggest why but-1-ene has a lower boiling point than acrylonitrile.
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Zadanie 7d
Explain why the complex ion [Cu(NH3)4]2+ is coloured.
Zadanie 8a
(i) Outline two differences between the bonding of carbon atoms in graphite and in diamond. (ii) Explain why fullerene, C60, sublimes at a much lower temperature than graphite.
Zadanie 8b
(i) State two features that show that ethene and propene are members of the same homologous series. (ii) The mass spectrum of pentane is shown. Suggest the species responsible for peak R. Use section 22 of the data booklet.
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Zadanie 8c
Two colourless liquids in unlabelled bottles are cyclohexane and cyclohexene. Describe a chemical test, and the expected observation with each liquid, that would show which bottle contains cyclohexene.
Zadanie 8d
(i) Write the equation for the reaction between hex-3-ene and hydrogen bromide. (ii) State the type of reaction in (i). (iii) Suggest two differences between the NMR spectra of hex-3-ene and of the organic product in (i). Use section 21 of the data…
Zadanie 8e
(i) Explain the mechanism of the reaction between 1-chloropropane, CH3CH2CH2Cl, and aqueous potassium hydroxide, KOH(aq), using curly arrows to represent the movement of electron pairs. (ii) Deduce the splitting pattern, in the NMR…
Zadanie 8f
Ethane reacts with iodine vapour. C2H6(g) + I2(g) → C2H5I(g) + HI(g) (i) Calculate the enthalpy change of the reaction, ΔH, using section 12 of the data booklet. (ii) Draw and label an enthalpy level diagram for this reaction on the axes below.
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