The part of the total energy of a system that accounts for the useful work done in a system is known as

Which of the following factors will speed up the rate of evolution of carbon (iv) oxide in the reaction below?
2HCl + CaCO\(_3\) → CaCl\(_2\) + H\(_2\)O + CO\(_2\)

(a) (i)  List the two gaseous fuels produced from coke.
(ii) Which of the two fuels listed in 5(a)(i) is a better fuel?
(iii) Give reasons for your answer in 5(a)(ii)
(iv) Write a balanced equation for the production of each of the fuels.      [9 marks]

(b)(i)  Differentiate between thermosets and thermoplastics.
(ii)   Give one example of:
I.   thermosets;
II.  thermoplastics.

(iii)  State three properties of plastics.

(c)(i) State the method of collecting gases which are denser than air.
(ii)  Name two gases that could be used to perform the fountain experiment in the laboratory.
(iii)  State the physical properties of the gases named in 5(c)(ii) which makes them suitable for the experiment.   [4 marks]
(d) (i)  State two compounds that could be used to test for water.
(ii)  Give three disadvantages of hard water.                  

1. (a ) Define the term compound.                                                

(b) State two conditions necessary for the cracking of petroleum fractions.            

(c) Name two transition elements that are used as catalyst.     
(d) (i) Write an equation for the reaction between zinc dust and trioxonitrate (V) solution.

   (ii) Which of the reactants in 1(d)(i) is:
I. reduced;
II. oxidized.                                                            

(e) Two isotopes of oxygen 16O and 18O have relative abundance of 90 % and 10 % respectively. Calculate the relative atomic mass of oxygen.            

(f)  List two ores of iron.                   

(g) (i)   What is biotechnology?                                 
(ii)   Name one product that can be obtained using biotechnology. 
(h) Define the term element.                                                          

(i)  State two sources of methane in the atmosphere.                    

(j)  Explain briefly why the trend of the boiling points for group VII elements is in the order I\(_2\) > Brl\(_2\)> Cl\(_2\).

(a) Explain the statement, the standard electrode potential of zinc is -0.76 v.What is meant by the term periodic property of elements?

(b) Consider the following standard electrode potentials:
Zn\(^{2+}\)\(_{(aq)}\) + 2e\(^-\)           Zn(s) Eᶿ  = - 0.76 V
Cu\({2+}\)\(_{(aq)}\)  +  2e\(^-\)        Cu(s)  Eᶿ = + 0.34 V

    When the two half cells are connected:
(i)         write the reaction equation at each electrode;
(ii)        write the overall cell reaction equation;
(iii)       state the type of reaction occurring at each electrode;
(iv)       calculate the e.m.f. of the cell.                    

(c) (i)    Name two chemical industries.
(ii)    State two factors that should be considered when siting a chemical industry.
(iii)       List two effects of a chemical industry on the community in which it is sited.              

(d)   Using chemical equations, explain briefly what would happen when hydrogen peroxide is added to:

(i)         silver oxide;
(ii)        chlorine gas.                                 

(e)        List three physical properties of nitrogen.