(a)(i) State the two types of hardness in water.
(ii) Name a salt that causes each type of hardness.
(ii) Write a balanced equation for the removal of each type of hardness.
(iv) State one effect of hard water on soap.
(b)(i) State whether the pH of each of the following is less than, equal to, or greater than 7.
I. Glucose solution II. Chlroine water III. Lime water IV. Sour milk
(ii) Give the difference between the following compounds: I. an acidic oxide and an amphoteric oxide; II. concentrated acid and a dilute acid; Ill. a normal salt and an acid salt
(c)(i) Iron reacts with H\(_2\)SO\(_4\) according to the equation: Fe\(_{(s)}\) + H\(_2\)SO\(_{4(aq)}\) ---> FeSO\(_{4(aq)}\) + H\(_{2(g)}\)
Calculate the mass of FeSO\(_4\) that would be produced by 0.5 mole of Fe. [H = 1, S = 32, Fe = 56]
(ii) List two allotropes of sulphur
(d)(i) State what would La observed when a damp starch-iodide paper is dropped into a gas jar of chloride
(ii) Explain your ansv.er in (d)(i) above.
(iii) State the products formed when ammonia reacts with excess chlorine.
(i) Name two amorphous forms of carbon
(ii) State the reason why graphite is a lubricant but diamond is not.
(iii) Draw and label a diagram for the laboratory preparation of a dry sample of carbon (IV) oxide.
(b)(i) Give one example of the following: I. Soil pollutant; II. Water pollutant; III. Air pollutant.
(ii) State the major use of sulphur (IV) oxide in a chemical industry.
(c)(i) Explain in terms of the kinetic theory why petrol is volatile
(ii) State two criteria for determining the purity of a substance.
(iii) Mention one use of each of the following gases: I. Krypton; II. Argon
(d)(i) When zinc metal was added to aqueous copper (I) tetraoxosulphate (VI), the solution turned colourless. I. Name the compound in the colourless solution. II. Write the ionic equation for the reaction. Ill. State what would be observed when a few drops of sodium hydroxide solution is added to a portion of the colourless solution.
(ii) Calculate the volume of CO\(_2\) produced when 5.3g of Na\(_2\)CO\(_3\) reacted with excess HNO\(_{3(aq)}\) + Na\(_2\)CO\(_3\) + 2HNO\(_{3(aq)}\) \(\to\) 2NaNO\(_{3(aq)}\) + CO\(_{2(g)}\) + H\(_2\)O\(_{(l)}\) [H = 1, C = 12, N = 14, O = 16, Na = 23, 1 mole of a gas occupies 22.4 dm\(^3\) at s.t.p.]
(a)(i) Mention two types of bond present in the ammonium ion
(ii) Give three characteristic properties of electrovalent compounds
(iii) State. two differences between chemical reactions and nuclear reactions
(b) Two elements represented by the letters and Y have atomic numbers 9 and 12 respectively.
(i) Write the electronic configuration of X using the s,p,d, notation
(ii) To what group does Y belong in the periodic table?
(iii) Write the formula of the compound formed when X copibines with Y
(iv) Explain wily X is a good oxidizing agent
(v) State with reason, whether Y would be expected to form acidic or basic oxide
(c) Balance the following nuclear equations and identify the particles represented by X and Y.
(i) \(^{14}_6C\) \(\to\) X + \(^{14}_7N\)
(ii) \(^{14}_7C\)
Y \(\to\) \(^1_1H\) + \(^{17}_8O\)
(d) Consider the following list of substances: Carbon (IV) oxide, hydrogen, zinc, sulphier, methane, potassium and mercury. From the list above, state the:
(i) elements that are metals
(ii) compounds that are gases at room temperature
(iii) non-metals that are solids at room temperature
(i) State Two assumptions of the kinetic theory of gases
(ii) When some solids are heated, they change directly into the gaseous state. What narne is given to this phenomenon?
(iii) List two substances which exhibit the phenomenon referred to in (a)(ii) above
(iv) Write an expression to show the mathematical relationship between the rate of diffusion of a gas and its vapour density.
(b) Consider the following equilibrium reaction:
3Fe\(_{(s)}\) + 4H\(_2\)O\(_{(g)}\) \(\rightleftharpoons\) FeO\(_3\)O\(_{4(s)}\) + 4H\(_{2(g)}\), \(\Delta\)H = - 150KJ mol\(^{-1}\)
Explain the effect of the following factors on the position of equilibrium: (i) tecrease in temperature; (ii) Increase in pressure; (iii) Removal of hydrogen.
(c) . Three beakers labelled P, Q and S each contained zinc metal of the same mass but in different forms. P contained a length of zinc rod, Q contained zinc dust while S contained zinc foil. 100cm\(^3\) of 5.0 mol dm\(^{-3}\) hydrochloric acid was added to each beaker to react with all the zinc.
(i) State the order in which the reaction came to completion in beakers P,Q and S starting with the fastest.
(ii) Give reason for your answer in (c)(i) above
(iii) Write an equation to represent the reaction between zinc rid the hydrochloric acid.
(d) (i) What is meant by pH of a solution?
(ii)(I) State with reason in each case whether the pH would increase, decrease or remain constant if the following experiments were carried out Neutralizing bench HNO\(_3\);
II. Diluting 25.0 cm\(^3\) of a given NaOH solution to 100.0cm\(^3\) Concentrating a solution of NaCI.
(a) Draw an energy profile diagram to illustrate a catalysed exothermic reaction and label parts of the curves representing the following:
(i) activated complex (without catalyst);
(ii) activated energy (with catalyst)
(iii) enthalpy change
(b) Give the reasons for the following observations:
(i) A balloon filled with liyilrogen becomes deflated faster than a balloon filled with air under the same conditions.
(ii) Hydrogen peroxide decomposes slowly at room temperature but when a pinch of MnO, is added, bubbles form rapidly.
(iii) A solution of hydrogen chloride as in methylbenzene has no effect on `litmus but a solution of the gas in water turns blue litmus paper red.
(c) Consider the reaction represented by the following equation: 2MnO\(^-_{4(aq)}\) + 5C\(_2\)O\(^{2-}_4\) + 16H\(^+\) \(\to\) 2Mn\(^{2+}_{(aq)}\) + 8H\(_2\)O\(_{(l)}\) + 10C\(_{2(g)}\) .
Write down: (i) the species undergoing reduction giving reasons;
(ii) the reducing agent giving reasons;
(iii) the reduction half equation;
(iv) one observation made during the reaction.
(d)(i) What is an electrochemical cell?
(ii) State three differences between an electrochemical cell and an electrolytic cell.
