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Like aluminium chloride, iron(III) chloride forms dimers in the vapour phase. Iron, however, is a transition element and aluminium is not. (i) Outline, in terms of its electronic structure, what identifies a transition element. (ii) The graph shows the first…
(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 booklet. (ii) Deduce whether this reaction is spontaneous under standard conditions at 298 K, and give a reason.
Explain, in terms of nuclear charge, sub-levels and shielding, why magnesium has a higher first ionization energy than both sodium and aluminium.
Outline how data from the atomic emission spectrum of aluminium could be used to find its first ionization energy.
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…
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…
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.
A sample of the protein is completely hydrolysed to a mixture of amino acids. Outline how paper chromatography can be used to identify the amino acids in this mixture when samples of the pure amino acids are available for comparison.
The concentration of protein in an extract can be found by mixing it with a dye that binds to protein and measuring the absorbance at 595 nm. The calibration line for standard protein solutions is shown. Its equation is y = 0.2903x + 0.0090, where y is the…
Butanone can be synthesised from but-1-ene in a two-stage process. In the first stage the alkene reacts with water in the presence of sulfuric acid to form the intermediate compound [X]; in the second stage [X] is converted into butanone by reagent B. (i) Draw…