Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
Dodaj cały arkusz do zestawu(i) The first step is the catalytic oxidation of ammonia gas to nitrogen monoxide. 4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g) Determine the volume, in dm3, of nitrogen monoxide produced from 20.0 g of ammonia, at STP, using section 2 of the data booklet.…
The second step converts nitrogen monoxide to nitrogen dioxide. 2 NO(g) + O2(g) ⇌ 2 NO2(g) ΔH⊖ = −114 kJ mol−1 (i) Identify the oxidation state of nitrogen in NO and in NO2. (ii) State the equilibrium constant…
The final step can be summarized as: 3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g) ΔH⊖ = −138 kJ mol−1 (i) Sketch an energy profile for the overall reaction, indicating ΔH⊖ and the activation energy. (ii) Describe the…
Nitric acid, HNO3, is strong, while nitrous acid, HNO2, is weak. (i) Outline the difference between a strong and a weak acid. (ii) Deduce the Lewis formula and the molecular geometry for the nitrite ion, NO2−. (iii) State the hybridization…
Many rechargeable batteries use an alkaline electrolyte. In the nickel-cadmium cell, cadmium, Cd, is the anode. Cd(OH)2(s) + 2 e− → Cd(s) + 2 OH−(aq) E⊖ = −0.81 V…
Energy can also be produced by a hydrogen-oxygen fuel cell that uses an aqueous solution of sodium hydroxide as the electrolyte. Hydrogen gas is fed to the anode and oxygen gas to the cathode. (i) Deduce the half-equations for the electrode reactions in this…
(i) State the number of protons, electrons and neutrons in . (ii) State the full electron configuration for . (iii) The relative atomic mass, Ar, of Rb is 85.47. Determine the relative mass of the first isotope of Rb to four…
(i) Explain why Rb has a lower first ionization energy than strontium, Sr. (ii) Outline why Rb has a lower electronegativity than potassium, K. (iii) Explain why oxygen, O, has a lower first ionization energy than nitrogen, N.
(i) Write the equation for the reaction of Rb with water, H2O, including state symbols. (ii) Describe the type of bonding in Rb and in H2O, and explain how the valence electrons in each produce that type of bond.
Rubidium also forms compounds with halogens such as chlorine, Cl. Annotate the Born–Haber cycle for rubidium chloride, RbCl, with the correct values in the boxes A, B and C. Use sections 9 and 12 of the data booklet.
(i) Iron, Fe, is a transition element. State two properties typical of transition elements that iron shows, other than the formation of coloured compounds. (ii) Explain why aqueous solutions containing the hexaaquacopper(II) ion, [Cu(H2O)6]2+,…
(i) Determine the enthalpy of combustion of pentane, in kJ mol−1, using table 12 in the data booklet. C5H12(g) + 8 O2(g) → 5 CO2(g) + 6 H2O(g) (ii) Calculate the mass, in g, of carbon dioxide, CO2, produced when 45.0 g of pentane react with…
Pentane reacts with bromine, Br2, to form 2-bromopentane. (i) Explain, using equations, the initiation step and two propagation steps for this reaction. (ii) 2-Bromopentane reacts with aqueous sodium hydroxide, NaOH(aq), to form pentan-2-ol,…
Pentan-2-ol can form by reacting pent-1-ene with water in the presence of an acid catalyst. CH2=CHCH2CH2CH3(g) + H2O(l) → CH3CH(OH)CH2CH2CH3(aq) ΔH⊖ = −84 kJ mol−1 (i) The first step of the mechanism for the formation of…
Pentan-2-ol will react with acidified potassium dichromate, K2Cr2O7, which is an oxidizing agent. (i) State the name of the product of this reaction. (ii) Explain how infrared spectroscopy could be used to distinguish between pentan-2-ol and the product…
Calculate the pH of a 0.125 mol dm−3 solution of sodium hydroxide.
A sample of the sodium hydroxide solution is gradually added to 25.0 cm3 of an aqueous solution of an unknown organic acid, producing the following pH curve. Calculate the concentration of the unknown organic acid.
The titration curve below was obtained when the sodium hydroxide solution was added to 25.0 cm3 of the unknown organic acid in part (b). State, with a reason, which indicator would be appropriate for this titration, using section 18 of the data booklet.
Suggest two different mixtures, each prepared from the unknown organic acid, that would produce a buffer solution.
Determine the order of reaction with respect to ClO2 and with respect to OH−.
Deduce the rate equation for the reaction.
Calculate the rate constant using the data from experiment 1 and include its units in your answer.