(a)(i) Define hard water (ii) Name two substances responsible for hardness in water (iii) Give two methods for the removal of hardness in water. (b)(i) What...

 (a)(i) Define hard water

(ii) Name two substances responsible for hardness in water

(iii) Give two methods for the removal of hardness in water.

(b)(i) What are the raw materials require for the manufacture of tetraoxosulphate (VI) acid by the contact process?

(ii) Write an equation for tr reaction that requires a catalyst in the contact process (iii) State the catalyst used in (b)(ii).

(c)(i) Give two uses of sodium tetraoxosulphate (VI) Consider the reaction represented by the following equation:

Na\(_2\)SO\(_4\).10H\(_2\)O\(_{(s)}\)  \(\to\) Na\(_2\)SO\(_4\).H\(_2\)O + 9H\(_2\)O\(_{(g)}\)

(ii) What name is given to this type of reaction?

(iii) Calculate the solubility of Na\(_2\)CO\(_3\) at 25°C. if 30.0 cm\(^3\) of its saturated solution at that temperature gave 1.80 g of the anhydrous salt. [C = 12, 0 = 16, Na = 23]

(d)(i) Define the term activated complex

(ii) State one reason why a collision may not produce a chemical reaction

(iii) The formation of water gas is represented by the following equation:

C\(_{(s)}\) + H\(_2\)O\(_{(g)}\) \(\to\) CO\(_{(g)}\) + H\(_{2(0)}\) \(\Delta\)H= + 131 kJmol\(^{-1}\)

Draw an energy profile diagram for the reaction showing the I. activated complex, II. enthalpy of reactants.