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Ethanoic acid is a weak monobasic acid. The acid dissociation constant of ethanoic acid at 298 K is Ka = 1.74 × 10−5. (i) A student dissolved a sample of ethanoic acid in water and made the solution up to 2.00 dm3. Exactly 19.4…
(i) Identify the dependent variable plotted on the graph. (ii) Calculate the decrease in the concentration of vitamin C, in μg cm−3, caused by the heat treatment. (iii) Calculate the average rate of decrease of the vitamin C concentration in…
UV-C irradiation is an alternative to heat treatment that causes less loss of nutrients. The absorption spectrum of a solution of vitamin C is shown. (i) Deduce the type of electromagnetic radiation absorbed by vitamin C. Use section 5 of the data booklet.…
The concentration of vitamin C and the pH of juice from five different fruits were measured. Deduce, with a reason, whether the data show a correlation between the concentration of vitamin C and pH.
The concentration of vitamin C in juice can be measured by a redox titration. A sample of acidified juice containing excess iodide ions and starch solution is titrated with potassium iodate solution. Iodate ions react with iodide ions to produce iodine…
Metal M reacts with 8.00 g of oxygen to produce 28.0 g of the oxide MO2. What is the relative atomic mass of M? A. 20 B. 40 C. 80 D. 160
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.
State the expression for the equilibrium constant, Kc, of this reaction.
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…
Suggest why the value of the equilibrium constant changes very little with temperature.