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Dodaj cały arkusz do zestawuThe graph shows the boiling points of the straight-chain alkenes with a terminal double bond, from ethene to hex-1-ene. (i) Explain why the boiling point rises from ethene to but-1-ene. (ii) A sample of but-1-ene is warmed from 250 K to 300 K at constant…
Ethane reacts with bromine gas, Br2(g), in the presence of UV light to form bromoethane. State the type of this reaction and the name of its mechanism.
1-Bromopropane can be converted into propan-1-ol. Identify a suitable reagent and the conditions needed for this conversion.
2-Methylbut-1-ene contains sigma (σ) and pi (π) bonds. (i) State the hybridization of carbon atoms A and B. (ii) Describe how the sigma bond and the pi bond of the carbon-carbon double bond in 2-methylbut-1-ene are formed.
2-Methylbut-1-ene reacts with hydrogen bromide, HBr, to give two structural isomers of C5H11Br. (i) Deduce which of the two isomers is formed in the larger amount and explain your choice. (ii) Using curly arrows to show the movement of electron pairs,…
In the solid state, calcium, Ca, and calcium chloride, CaCl2, are each built as a regular three-dimensional lattice. Predict the electrical conductivity of Ca(s) and of CaCl2(s), giving a reason for each.
(i) A dilute aqueous solution of sodium chloride is electrolysed using inert electrodes. Give the half-equation for the process at the anode and the half-equation for the process at the cathode. Use section 19 of the data booklet. (ii) Identify the product at…
Give the number of protons, electrons and neutrons in the calcium ion, .
Outline the experimental evidence for four main energy levels in a calcium atom.
Calcium reacts with water to form calcium hydroxide solution and hydrogen gas. Ca(s) + 2 H2O(l) → Ca(OH)2(aq) + H2(g) (i) Calculate the enthalpy change, in kJ, when 5.00 g of calcium reacts completely with water. Use section 13 of the data booklet.…
Sulfur dioxide, SO2, can be represented by more than one Lewis (electron dot) structure. (i) Sketch two different Lewis (electron dot) structures of SO2, one in which all atoms obey the octet rule and one in which sulfur does not. (ii) State the…
Suggest why sulfur dioxide released into the atmosphere is an environmental concern.
Sulfuryl chloride, SO2Cl2, is made industrially from sulfur dioxide and chlorine in the presence of an activated carbon catalyst. SO2(g) + Cl2(g) ⇌ SO2Cl2(g) ΔH⊖ < 0 (i) Sketch a potential energy profile for the forward reaction,…
In a titration, 25.00 cm3 of a 0.120 mol dm−3 solution of a weak monoprotic organic acid, HA, was neutralized by adding sodium hydroxide solution, NaOH(aq), from a burette. The pH curve obtained is shown. (i) Determine the…
Outline how 0.100 mol dm−3 solutions of ethanoic acid and nitric acid could be told apart.
The ionic product constant of pure water, Kw, is 1.00 × 10−14 at 25 °C and 5.48 × 10−14 at 50 °C. (i) Suggest why the value of Kw for pure water becomes larger as the temperature rises. (ii) Calculate both the pH and the pOH of pure…
(i) Predict the number of signals in the 1H NMR spectrum of 3-methylbutanoic acid and the ratio of their areas. (ii) Predict the splitting pattern of the signal due to the two hydrogen atoms of the CH2 group. (iii) State one reason why…
The mass spectrum of 3-methylbutanoic acid is shown. (i) Suggest why the spectrum shows a small peak at m/z 103. (ii) Identify the fragments responsible for the peaks at m/z 87 and m/z 57. Use section 22 of the data booklet.
Predict one wavenumber at which an absorption, other than that of a C–H bond, appears in the infrared spectrum of 3-methylbutanoic acid. Use section 20 of the data booklet.
3-Methylbutanoic acid reacts with propan-1-ol, CH3CH2CH2OH, to form an organic product and water. Deduce the structural formula and the empirical formula of the organic product.
Nitrogen dioxide, NO2, is one of the brown pollutant gases in photochemical smog. It can react with carbon monoxide, which is also present in polluted air. NO2(g) + CO(g) → NO(g) + CO2(g) (i) Suggest how the rate of this reaction could be…
The nitrite ion, NO2−, can form complexes with transition element ions such as Co3+ and Ni2+. Describe the type of bonding between the nitrite ion and the metal ion in such a complex, and state the role of the nitrite ion in acid-base…
Identify the species that is oxidized in step 2 and give a reason.
In step 3, 3.00 × 10−4 mol of thiosulfate ions, S2O32−, reacted completely with the iodine formed in step 2. Determine the amount of O2, in mol, in the water sample.
Calculate the concentration of oxygen in the water sample, in g dm−3. If you could not answer (b), use 2.00 × 10−4 mol instead; this is not the correct value.
The diagram shows the apparatus. The left-hand half-cell is the anode and the right-hand half-cell is the cathode; the electrodes and solutions are not labelled. State which electrode and which solution are in each half-cell, and state the direction of…
Outline the function of the salt bridge in this cell.