(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.