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Which calculation gives the standard enthalpy change of formation of nitrogen monoxide, in kJ, from the data below? A. (+66) + (−114) B. 0.5 × (+66) + 0.5 × (−114) C. (+66) − (−114) D. 0.5 × (+66) − 0.5 × (−114)
Some bacteria can be used in microbial fuel cells to oxidize aqueous lactate ions, CH3CH(OH)COO−(aq), to carbon dioxide gas. Oxygen gas is reduced at the other electrode. The cell operates in acidic conditions. Deduce the half-equations for the…
A hydrogen fuel cell and a rechargeable lithium-ion cell can both be used to supply electricity again and again. Describe, for each type of cell, what must be done so that it can be used again after the cell can no longer supply electricity.
The diagram shows the enthalpy profile of an exothermic reaction. Arrows I, II and III show energy differences on the profile. Which expression gives ΔH for the forward reaction? A. II − I B. I − II C. I + II D. III − II
Benzocaine, a local anaesthetic, is the ethyl ester of 4-aminobenzoic acid. The crude product of its synthesis is purified by recrystallization. (i) Discuss two ways in which the melting point of the recrystallized benzocaine can show that it still contains…
A tablet contains either aspirin or paracetamol as its active ingredient. The structures of the two compounds and the IR spectrum of the active ingredient are shown. Deduce whether the active ingredient is aspirin or paracetamol, and give two reasons that…
Which expression gives the enthalpy change, ΔH, of the forward reaction shown in the enthalpy profile? A. II − I B. I − II C. I − III D. III − II
Benzocaine is a local anaesthetic. It is made by reacting the carboxylic acid X with ethanol. (i) Discuss two ways in which the melting point of a crystallized sample of benzocaine can show that it still contains X. (ii) Deduce the range of wavenumbers in the…
Menthol is a secondary alcohol used in cough lozenges. A chemist heated menthol with an oxidizing agent and isolated the product, which is either unreacted menthol or its oxidation product menthone. The structures of the two compounds and the IR spectrum of…
Magnesium hydroxide is used as an antacid to neutralize excess stomach acid, which is hydrochloric acid. Write an equation for the reaction between magnesium hydroxide and hydrochloric acid, including state symbols.