Zadanie 1a
Propanoic acid, CH3CH2COOH, is the next member of the series. Outline two characteristics that make ethanoic acid and propanoic acid members of the same homologous series.
Chemistry HL Paper 2, November 2023, TZ1
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 zestawuZadanie 1b
Calculate the percentage by mass of carbon in ethanoic acid.
Zadanie 1c
Ethanoic acid and propanone, CH3COCH3, each contain a C=O group, and their molar masses are close. (i) Considering the strongest intermolecular forces in each liquid, explain why propanone boils at a much lower temperature than ethanoic acid.…
Zadanie 1d
Ethanoic acid acts as a weak monoprotic acid in aqueous solution. At 298 K its acid dissociation constant is Ka = 1.74 × 10−5 mol dm−3. (i) 2.00 dm3 of an ethanoic acid solution was prepared. A 25.0 cm3…
Zadanie 2a
Hydrogen iodide is an intermediate in some thermochemical cycles that are being researched as a way of obtaining hydrogen from water without using fossil fuels. Explain why there is great interest in producing hydrogen in this way.
Zadanie 2b
State the expression for the equilibrium constant, Kc, of this reaction.
Zadanie 2c
Approximate enthalpy changes of reactions can be found from bond enthalpies. (i) Determine the enthalpy change, ΔH⊖, of this reaction, in kJ mol−1, using section 12 of the data booklet. (ii) Each bond enthalpy is uncertain by 0.1…
Zadanie 2d
Suggest why the value of the equilibrium constant changes very little with temperature.
Zadanie 2e
Calculate the standard entropy change, ΔS⊖, of the reaction, using section 13 of the data booklet and the values given:
- Tabela do uzupełnienia
Zadanie 2f
The reaction is usually carried out at a high temperature in the presence of a catalyst. (i) On the axes provided, sketch the energy profile of the reaction for the uncatalysed and for the catalysed pathway, and show ΔH and the activation energies.…
- Materiał graficzny
Zadanie 2g
Determine the oxidation state of iodine in the iodate ion, IO3−.
Zadanie 3a
State the name of the reagent that is heated with ethanoic acid to form this ester.
Zadanie 3b
A student obtained 2.58 g of the ester from 3.00 g of ethanoic acid and an excess of the second reagent. Determine the percentage yield of the ester.
Zadanie 3c
Spectra can be used to monitor the conversion of ethanoic acid into the ester. (i) State one similarity and one difference between the infrared (IR) spectra of ethanoic acid and of the ester in the 1500–3500 cm−1 region. Use section 20 of the…
- Materiał graficzny
Zadanie 3d
State the homologous series to which CH3COOCH3 belongs.
Zadanie 4a
(i) Calculate the enthalpy change of this reaction using section 13 of the data booklet together with the values given below: (ii) Outline why the entropy change of this reaction is expected to be small. (iii) Ignoring any entropy change, estimate the…
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Zadanie 4b
Deduce the molecular geometry of COS and of H2S, and state why the two geometries differ.
Zadanie 4c
Naturally occurring sulfur is a mixture of several isotopes. A sample was enriched in , giving the following composition: (i) Calculate the relative atomic mass of the enriched sample to two decimal places. (ii) The abundance of…
- Tabela do uzupełnienia
Zadanie 5a
Outline the nature of the electrostatic attraction that holds together the crystal structure of solid aluminium.
Zadanie 5b
Aluminium is produced industrially by the electrolysis of aluminium oxide dissolved in molten cryolite, as shown in the diagram. (i) Outline why the molten mixture is considered to be an electrolyte. (ii) Identify the electrode at which aluminium forms and…
- Materiał graficzny
Zadanie 5c
Aluminium forms a chloride, AlCl3. (i) Draw the Lewis (electron dot) structure of the AlCl3 molecule. (ii) Outline why the Lewis structure of AlCl3 is an exception to the octet rule.
Zadanie 5d
In the gas phase, some AlCl3 molecules join in pairs to form this dimer: (i) Identify the hybridization of the aluminium atom in the dimer, Al2Cl6. (ii) Describe, in terms of Lewis acids and bases, how two AlCl3 molecules bond together to…
- Materiał graficzny
Zadanie 5e
Manganese, unlike aluminium, is a transition element. (i) Deduce, from the electron configuration of the Mn2+ ion, why manganese is classified as a transition element. (ii) The first four ionization energies of aluminium and manganese are shown. One…
- Materiał graficzny
Zadanie 5f
The standard electrode potential, E⊖, of the half-cell Al3+(aq) + 3 e− ⇌ Al(s) is −1.66 V. (i) Calculate the standard cell potential for the reaction 2 Al(s) + 6 H2O(l) → 2 Al3+(aq) + 6 OH−(aq) + 3 H2(g) Use section 19 of the data…
Zadanie 5g
Using nuclear charge, electron sub-levels and the shielding by filled inner shells, explain why the first ionization energy rises from sodium to magnesium but falls from magnesium to aluminium.
Zadanie 5h
Outline how the atomic emission spectrum of aluminium could be used to find its first ionization energy.
Zadanie 6a
Butanone can be synthesized from but-1-ene in a two-stage process. In the first stage but-1-ene reacts with water and sulfuric acid to form an intermediate compound X. In the second stage X reacts with reagent B to form butanone. (i) Draw the structural…
- Materiał graficzny
Zadanie 6b
Heating benzaldehyde with concentrated nitric and sulfuric acids nitrates the ring by the same type of reaction as in benzene. The acid mixture generates the electrophile NO2+, and the product is 3-nitrobenzaldehyde. Explain the mechanism of this…
- Materiał graficzny
Zadanie 6c
The rate constant of a reaction increases by a factor of 2.5 when the temperature is raised from 30 °C to 40 °C. Deduce the activation energy of the reaction, in kJ mol−1. Use sections 1 and 2 of the data booklet.