S4 Mot One 2020 Chem 2 Caltec S.4

1 Name:……………………………………………… …………...Signature:…………...... Stream:..... 545/2 CHEMISTRY Paper 2 Mar./April.2020 S.4 2 hours. THE CHEMISTRY DEPARTMENT MIDTERM ONE EXAMINATIONS -2020 CHEMISTRY Paper 2 2 hours 30 minutes INSTRUCTIONS: Section A consists of 10 structured questions. Answer all questions in this section. Answers to these questions must be written in the spaces provided. Section B consists of 4 semi -structured questions. Answer any two questi ons from this section. Answers to these questions must be written in the answer booklet(s) provided. In both sections all working must be clearly shown. Where necessary use; [H=1; C=12; N=14; O=16; Na=23; S=32; Cl=35.5 ] 1 mole of gas occupies 24l at room temperature 1 mole of gas occupies 22.4 l at s.t.p. For Teachers’ Use Only 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Total 2 SECTION A (50 MARKS) Answer all questions in this section. 1. (a) Name two liquids that are; (i) miscible (01 mark) ............................................................................................................................. .............. ......................................................... .................................................................................. (ii) immiscible (01 mark) .................................................................................. ......................................................... ............................................................................................................................. .............. (b) State a method, which can be used to separate component s of the liquid mixture in; (i) a(i) above. (01 mark) ........................................................................................................................... ................ (ii) a(ii) above. (01 mark) ............................................................................................................................. ......... ..... (c) Name two substances that would form a mixture that can be separated by fractional crystallization. (01 mark) .................................................................................................. ......................................... ............................................................................................................................. .............. 2. A hoe left in the garden for some weeks, was found coated with some brown s olid deposits. (a) (i) Write the chemical formula of the brown solid. (01 mark) ............................................................................................................................. .............. (ii) State the conditions w hich led to the formation of the solid. (01 mark) ............................................................................................................ ................... (b) (i) State two methods by which formation of the brown solid can be prevented. (02 marks) ........................................................................... ................................................................ ............................................................................................................................. .............. 3 (ii) Give one reason …