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Which statement best explains why the boiling points of the straight-chain alkanes rise from methane to pentane? A. The carbon–hydrogen bonds become stronger B. Longer molecules have more electrons, so the London (dispersion) forces between them are stronger…
Which products could be obtained by heating isomers of C4H10O under reflux with excess acidified potassium dichromate(VI)? I. 2-methylpropanal II. butanone III. butanoic acid A. I only B. II and III only C. I and III only D. I, II and III
What is the preferred IUPAC name of the compound shown? A. 4-methylpentan-3-ol B. 3-methylpentan-2-ol C. 2-methylpentan-3-ol D. 1-isopropylpropan-1-ol
Bromine water, which is orange, is added to four organic compounds in the dark. In which case does the orange colour disappear? A. Pentane B. Pentan-2-ol C. Pent-2-ene D. Pentanoic acid
A student determined the enthalpy of combustion of a fuel as −680 kJ mol−1. The literature value is −850 kJ mol−1. What is the percentage error of the experimental result? A. 20 % B. 25 % C. 80 % D. 125 %
A student determines the formula of hydrated copper(II) sulfate, CuSO4 ⋅ x H2O, by heating a weighed sample until its mass is constant. Which observation would explain a systematic error in the value of x? A. The crucible was always weighed while it was…
Which source of error would be reduced by repeating the measurement and calculating the mean of the results? A. A balance reads 0.05 g too high for every object placed on it B. The student's judgement of the moment at which a cross disappears differs from…
The graph shows how the concentration of dinitrogen pentaoxide, N2O5, changes with time during its decomposition at constant temperature. What is the average rate of reaction, expressed as the rate of decrease in the concentration of N2O5, over…
Which hydrocarbon forms 4 mol of H2O for every 3 mol of CO2 upon complete combustion? A. C3H4 B. C3H6 C. C4H10 D. C3H8
Propanoic acid, CH3CH2COOH, is the next member of the series. Outline two characteristics that make ethanoic acid and propanoic acid members of the same homologous series.