Umiejętności z tego działu sprawdza 17 zadań wzorowanych na arkuszach IB z lat 2022–2026. Dział pojawia się w 16 z 54 arkuszy w bazie.
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,…
Methane reacts with bromine gas in the presence of UV radiation to produce brominated hydrocarbons. (i) Explain, using an equation, how a bromine molecule undergoes homolytic fission. (ii) Using two equations, explain the propagation steps in the substitution…
Ethane, C2H6, reacts with chlorine, Cl2, to produce chloroethane, C2H5Cl. (i) Outline why the reaction does not start unless the mixture is exposed to ultraviolet light. (ii) Deduce two propagation steps and one termination step for this…
Suppose carbonyl dibromide were made by a free-radical chain reaction of carbon monoxide, CO, with bromine vapour, Br2, started by ultraviolet light. The questions below treat this hypothetical route with the bond-enthalpy model and the entropy…
The rate of the reaction between compound Y and aqueous sodium hydroxide depends on the concentrations of both reactants. (i) Explain the mechanism of this reaction, using curly arrows to show the movement of electron pairs. (ii) Explain why…
Which equation represents a propagation step in the radical substitution of ethane by bromine? A. Br2 → 2 Br ⋅ B. ⋅ C2H5 + Br ⋅ → C2H5Br C. C2H6 + Br ⋅ → C2H5Br + H ⋅ D. ⋅ C2H5 + Br2 → C2H5Br + Br ⋅
(i) Concentrated sulfuric acid, H2SO4, is used as the catalyst in the manufacture of propyl ethanoate. Explain how the catalyst affects the reaction. (ii) The conversion of propane into 1-bromopropane,…
Chlorinated solvents such as tetrachloromethane, CCl4, and 1,1,1-trichloroethane, CH3CCl3, were once common in laboratories, but their production is now restricted by an international agreement. Besides climate change, state the specific…
Which radical is most likely to form when one covalent bond in bromochlorodifluoromethane, CBrClF2, is broken by ultraviolet light in the upper atmosphere? A. •CBrF2 B. •CClF2 C. •CBrClF D. •CBrClF2
(i) Iodine molecules, I2, undergo homolytic fission when they absorb light. Write an equation for this process, using curly arrows to show the movement of the electrons. (ii) In the presence of a suitable reagent the I–I bond can instead break…
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