Set 15 Chemistry [Paper] 1

‘When schools flourish, all flourishes’ Tr.Felix Js Rubangakene Geofrey Jr 1 SECTION A -46 MARKS Attempt all questions in this section. 1. The standard reduction electrode (E2) for some half cells are given in the table below. Half cell E2(v) Fe3+(aq), Fe2+(aq) +0.77 S(s), H2S(g) +0.14 a) Write the: i. Cell notation. (01 mark) ……………………………………………………………………………………………………… …………………………………………………………………………………………………….. ii. Equation of reaction that takes place at the cathode and anode respectively. (@01 mark) Anode: ……………………………………………………………………………………………………… …………………………………………………………………………………………………….. Cathode: ……………………………………………………………………………………………………… ……………………………… …………………………………………………………………….. b) Write the overall equation for the cell notation. (01 mark) ………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………….. c) State whether the reaction is feasible or not and give a reason for your answe r. (0½ mark) ………………………………………………………………………………………………………………… ……………………………………………………………………………………………………………….. ‘When schools flourish, all flourishes’ Tr.Felix Js Rubangakene Geofrey Jr 2 2. The decay law is given in the expression as shown below. -𝒅𝑵 𝒅𝒕 = λN a) (i) State what each symbol represent. (01 ½ marks) ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… (ii) Using the above expression derive the expression for the relation between half -life and the decay constant. (02 marks) ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ……………………………………………………………………………… ………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………… ………………………………………………………………………… ……………………………………… b) Nickel (63Ni) decays to copper (63Cu). i. Name the particle emitted and write the equation for the reaction: Name of particle: (0½ mark) ……………………………………………………………………………………………………… ‘When schools flourish, all flourishes’ Tr.Felix Js Rubangakene Geofrey Jr 3 Equation: (0½ mark) ……………………………………………………………………………………………………… …………………………………………………………………………………………………….. ii. Calculate the time taken for 𝟏𝟓 𝟏𝟔 of Nickel to decayed or changed to copper. [The half -life for Nickel is 120 years] (02 marks) ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… …………………………………………………………… ………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… ……………………………………………………………………………………………………… …………………………………………………………………………………………………….. 3. (a) State conditions for the reaction between aluminium oxide and sulphuric acid. Condition (s) : (0½ mark) …………………………………………………………………………………………………………………………… ………………………………………………………………………………………………………………………….. Equation (s): (01½ marks) …………………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………………… ‘When schools flourish, all flourishes’ Tr.Felix Js Rubangakene Geofrey Jr 4 …