Chemistry 1 Past Paper - Tanzania Examination 2023 - PDF

THEUNITED REPUBLICOF TANZANIA NATIONAL EXAMINATIONSCOUNCIL OF TANZANIA CERTIFICATEOF SECONDARY EDUCATION EXAMINATION 032/1 CHEMISTRY 1 (For Both School and Private Candidates) Time: 3 Hours...

THEUNITED REPUBLICOF TANZANIA NATIONAL EXAMINATIONSCOUNCIL OF TANZANIA CERTIFICATEOF SECONDARY EDUCATION EXAMINATION 032/1 CHEMISTRY 1 (For Both School and Private Candidates) Time: 3 Hours Year: 2023 Instructions This paper consists of sections A, Band Cwitha total of eleven (11) questions. 2. Answer all questions in sections A and B and two (2) questions from section C. 3. Sections A carries sixteen (16) marks, section B fifty four (54) marks and section C thirty (30) marks. 4. Non-programmable calculators may be used. 5. Cellular phones and any unauthorised materials are not allowed in the examination room. 6. Write your Examination Number on every page of your answer booklet(s). 7. The following constants may be used. Atomic masses: H=1, C= 12, 0= 16, S= 32. -l301032 100019 Page I of 6 ee2023  SECTION A16 Marks) Answer allquestions in this section Eor each of the items ()-(x). choose the correct answer irom the ive alternatives and write its letter in the answer booklet provided. () Which is the correct description of nucleons? A Nucleons are neutrons and protons in the nucleuS of an atom. B Nucleons are neutrons in the ucleus of an atom. C Nucleons are protons and electrons in the nucleus of an atom. D Nucleons are neutrons and electrons in the nucleus of an aton. E Nucleons are neutrons, protons and elecirons in the nucieus of an atom. (ii) Which one of the following characterises ions formation? A Metal atoms gaining electrons in their outermost shells. B Non-metal atoms losing electrons from their outermost sheils. C Metal atoms losing electrons from their innermost shelis. D Non-metal atoms gaining electrons in their innermost shells. E Metal atoms losing electrons from their outermost shells. (iii) The following are steps of writing ionic equation except A Writing the correct formula for the reaction. B Writing all soluble ionic substances. C Writing the reaction in words. D Writing all insoluble ionic products. reaction. E Writing balanced formula equation for the of oxygen Form Two student was given the following staffs for preparation (iv) A gas. Source of heat () (ii) Manganese dioxide (iii) Hydrogen peroxide (iv) Potassium Chlorate produce oxygen? Which combination will fast A (ii)and (iv) B (i)and (iii) C (iii)and (iv) D (i).(iii) and (iv) E (i). (Gi) and (iv)  elements in the Periodic Consler the ven irends m physical properties of Table ) lectton almity inercascs from left to right. ) Densities mercascs down the group. Mcltine pont of ictals inctcases down the group. right. (N Mctallic ch.cter imurease from left to trends? Whiuhcombination demonstrates correct Band (im) C wand (ii) D and (ii) reactedtogether to form compound C The organic compounds marked Aand B as show in the cquation: CHCTIOHi) 4 CII.COOi) Conc. H,SO CH,COOCH,CH,() B What are the hannes of compounds A, B andC? Ister.ctlatoic acdand alcohol. B Alcohol. catboxylic acid and ester. Alcohol. ester and carboxylic acid. D Ithanol. cthanorc acid and ethylethanoate. Cuboxsiie cid. ethanol and ethylethanoate. mole? Which ol the following does not constitute one A 32gof ovgen molccules. B Deothydiogen molecules. 19gof hvdroxonium ions. 8of carbon monoxide nolecules. 98 of ulphuric acid When t stdent mixed a solution of a certain copper (II) salt and sodium ydroxale. blue precipitate is forned. Which substance was produced? ACopper (ll) oxide BCoppes hydroide DCoperipoxde Coppt etal Pape 3 of 6  using washing soda. Which (ix) Permanent hardness of water can be removed by reaction is the correct ionic equation for the softening process? A Ca(aq) + SO, (aq) >CaSO, (aq) B Ca (aq) + CO; (aq) CaCO; (s) C Mg"(aq)+ SO, (aq) MgSOaaq) D Ca' (aq) + 2HCO,- (aq) Ca (HCO;)2 (aq) E Mg* (aq) + 2HCO; (aq) ’Mg (HCO;)2 (aq) (x) Why sodium hydroxide pellets should be stored in aclosed container? A Sodium hydroxide is efflorescence. B Sodium hydroxide is hygroscopic. C Sodium hydroxide is deliquescent. D Sodium hydroxide is volatile. E Sodium hydroxide is flammable. 2. Match the chemical equations in List A with the corresponding types item of chemical reactions in List Bby writing the letter of the correct response beside the number in the answer booklet provided. List A List B NH;(g) + HCI(g) NH,Cl(s) A Endothermic reaction (i) B Ionic reaction (i) C(s) + O(g) ’ CO:(g) + Heat Exothermic reaction (iii) 2C(s)+ 2H(g) + Heat ’ CHA(g) D Neutralization reaction (iv) N(g) + 3H2(g) ’ 2NH3(g) E Reversible reaction (v) H,SO(aq) + 2KOH(aq) ’ K,SO,(s) + 2H,0(1) Homogeneous reaction G Displacement reaction (vi) CaCOs(s) >CaO(s) + COz(g) H Decomposition reaction SECTION B (54 Marks) Answer all questions in this section. 3. ITo'ne aschematic diagram, illustrate the correct sequence of urban water treatment Briefly explain the importance of a laboratory coat, safety goggles, gloves and 4. (a) protective masks. as safety equipment in the Chemistry laboratory. (b) Jdentify the uses ol the giVenapparatuses: (i) Reagent botle Filter funnel (ii) Page 4 of6  (ii) Pipette (iv) Mortar and pestle (V) Bunsen burner 5 Explain six scientific procedures used by scientists to investigate scientific problems. 6. (a) Justify cach of the following statements. () It is advisable to use an evaporating dish instead of conical flask to evaporate a solution. (ii) In filtration process, the filtrate passes through the filter paper while the residue does not. (ii) Melting of ice is regarded as a physical change. (iv) Rusting of iron is regarded as a chemical change. (v) Carbon is a non-metal. (b) Asolution of sugar is said to be amixture. Justify the statement using four points. 7. (a) (i) Why is it not advisable to examine a car battery using a burning candle light. (ii) Why is the blue colour disappears during electrolysis of copper (1) sulphate solutions using carbon electrode? (iii) Why is a concentrated sulphuric acid not an electrolyte? (b) With the aid of ionic equations at the anode and cathode, explain the difference between the electrolysis of dilute NaClusing carbon electrode and molten NaCl. 8. (a) With examples,explain the given terms as used in chemistry: (i)) Fire extinguisher (ii) Combustible material (b) ldentify four stages of extinguishing fire using acarbon dioxide extinguisher. (c) Suggest the three components needed to start fire. Page 5 of 6  SECTION C(30 Marks) Answer two (2)questions in this section. 9 You paid a visit to a certain village which has a scarcity of cooking fuel but plenty of raw materials for generating biogas. How would you advise the villagers with regard to the given aspects? (a) Nature of the gas. (b) Raw material for generating the gas. (c) The process involved in generating the gas. (d) Three advantages of using biogas over charcoal. 10. lustrate five environmental destructions caused by the process of extraction of metals and suggest five intervention measures to control the problem. 11. Using five points, explain the harmfuleffects of Terrestrial pollution. Page 6 of 6 (e.u,':