2019年5月IB化学SL真题下载-Paper3
1. Physical properties of elements vary according to atomic number. Sections 6 to 9 of the data booklet list some of these properties.
(a) Deduce, giving a reason, the group of elements in the periodic table most likely to undergo sublimation.
(b) (i) Describe the density trend across periods 4 and 5 of the periodic table.
(ii) Suggest, with a reason, whether the lanthanoids or actinoids of the f-block would have the higher density.
(iii) Compare the ease of oxidation of s-block and d-block metals to their melting points and densities. Use section 25 of the data booklet.
(iv) Sketch how the first ionization energies of elements vary with their atomic radius.
2. Powdered zinc was reacted with 25.00 cm3 of 1.000 mol dm−3 copper(II) sulfate solution in an insulated beaker. Temperature was plotted against time.
(a) (i) Estimate the time at which the powdered zinc was placed in the beaker.
(ii) State what point Y on the graph represents.
(b)(i) The maximum temperature used to calculate the enthalpy of reaction was chosen at a point on the extrapolated (dotted) line.
State the maximum temperature which should be used and outline one assumption made in choosing this temperature on the extrapolated line.
Maximum temperature:
Assumption:
(ii)To determine the enthalpy of reaction the experiment was carried out five times. The same volume and concentration of copper(II) sulfate was used but the mass of zinc was different each time. Suggest, with a reason, if zinc or copper(II) sulfate should be in excess for each trial.
(iii)The formula q = mcΔT was used to calculate the energy released. The values used in the calculation were m = 25.00 g, c = 4.18 J g−1 K−1.State an assumption made when using these values for m and c.
(iv)Predict, giving a reason, how the final enthalpy of reaction calculated from this experiment would compare with the theoretical value.
2019年5月IB化学SL真题余下省略！
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