(a) Explain in terms of the kinetic theory why a tyre should not be overinflated.
(b)The following results were obtained at room temperature in an experiment to verify one of the gas laws using a glass syringe:
Pressure (P) of air in syringe (atm)
Volume (V) of air in syringe (cm\(^3\)
\(\frac{I}{V}\)
0.100
10.00
0.100
0.125
8.00
0.125
0.150
6.60
0.150
0.175
5.60
0.179
0.200
4.80
0.208
0.225
4.40
0.227
(i) Plot a graph of P against \(\frac{1}{v}\), using 1 cm to represent 0.01 atm on the vertical axis and 1cm to represent 0.02 unit on the horizontal axis. (ii) Which of the gas laws is in agreement with the results?
(c) The flow chart below represents the stages involved in the manufacture of H\(_2\)SO\(_4\). +x +Conc. H\(_2\)SO\(_4\) +H\(_2\)O S + O\(_2\) \(\to\) SO\(_2\) \(\to\) SO\(_3\) \(\to\) Y \(\to\) Conc H\(_2\)SO\(_4\) stage I stage II stage III stage IV
(i) Name the process represented by the chart. (ii) Identify reactant X and product Y. (iii) What are the operating temperature and pressure at stage II? (iv) Mention the stage which requires a catalyst and state the catalyst used. (v) Give the reason why the SO\(_3\) produced in stage II is not dissolved directly in water to form the acid
(d) When K\(_4\)Cr\(_2\)C\(_7\) dissolves in water, the following equilibrium is established: Cr\(_2\)O\(^{2-}_{7(aq)}\) + H\(_2\)O\(_{(l)}\) \(\to\) 2CrO\(^{2-}_{4(aq)}\) + 2H\(_{aq}\) (i) State the colour observed on adding a few drops of dilute H\(_2\)SO\(_4\) to the system. (ii) Explain your answer in (d)(1).
(iii) What principle is applicable to this explanation?
Explanation
(a) As the vehicle moves, the gas particles in the tyre gain kinetic energy and the collision rate increases. This builds up the pressure in the type, if the tyre is overinflated, it may burst b)(i)
Pressure (P) of air in syringe (atm)
Volume (V) of air in syringe (cm\(^3\)
\(\frac{I}{V}\)
0.100
10.00
0.100
0.125
8.00
0.125
0.150
6.60
0.150
0.175
5.60
0.179
0.200
4.80
0.208
0.225
4.40
0.227
Scale: -1cm representing 0.01 unit on p axis = 1cm to 0.02 unit on the \(\frac{1}{v}\) axis
(ii) Boyle's Law
(C)(i) Contact process (ii) X is oxygen, Y is H\(_2\)S\(_2\)O\(_7\) (oleum) (iii) The temperature of about 450 - 500°C (iv) Stage II and the catalyst is V\(_2\)O\(_5\) (vanadium v oxide) (v) The oxide is not dissolved directly in water because the heat evolved causes the solution to boil, producing a mist of acid droplets which would pervade the factory
(d)(i) The colour change is from yellow to green (ii) The acidic property (of the gas SO\(_2\) from H\(_2\)SO\(_4\) i.e SO\(_4\)) causes the colour change. (iii) Principle of ion exchange through oxidation and reduction.
