Chemistry 1 Past Paper 2024 PDF

Find this and other free resources at: https://maktaba.tetea.org THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OFTANZANIA CERTIFICATE OF SECONDARY EDUCATIONEXAMINATION 032/1...

Find this and other free resources at: https://maktaba.tetea.org THE UNITED REPUBLIC OF TANZANIA NATIONAL EXAMINATIONS COUNCIL OFTANZANIA CERTIFICATE OF SECONDARY EDUCATIONEXAMINATION 032/1 CHEMISTRY 1 (For Both School and Private Candidates) Time: 3 Hours Year: 2024 Instructions This paper consists of sections A, Band Cwith a total of eleven (11)questions. Answer allquestions in sections Aand Band two (2) questions from section C. 3 Sections Acarries sixteen (16),marks, section Bfifty four (54) marks and section C thirty (30) marks. 4 Non-programmable calculators may be used. 5 Communication devices 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, N= 14, O = 16, Cl=35.5, Ca = 40 401032 10001b || Page 1of 6 Find this and other free resources at: ee21 https://maktaba.tetea.org  Find this and other free resources at: https://maktaba.tetea.org SECTION A(16 Marks) Answer allquestions in this section. 1. For cach of the items (i) -(x), choose the correct answer from thec given alternatives and write its letter in the answer booklet provided. (i) Which ideas were introduced by Dalton? () Atoms cannot be created or destroyed. (ü) Atoms of the same element may have different chemical propcrties. (ii) Atoms of different elements may have the same chemical properties. (iv) When atoms conmbine they do so in simple whole numbers to form compounds. A (ii) and (iv) B () and (iii) C (ii)and (ii) D (i) and (iv) E () and (ii) (ii) A Form Four student boiled a mixture of sun-flower oil and concentrated solution of sodium hydroxide for a certain period of time. After cooling, sodium chloride salt was added to the mixture. What was the aim of this experiment? A To prepare an alcohol B To prepare a solid soap C To prepare sodium metal D To prepare a carboxylic acid E To prepare an organic compound (iiü) In Periodic Table, hypothetical clements X and Y are found in group VI and Il respectively. What is the correct formula for the compound formed between the two elements? A XY B YX C X6Y: D YX6 E X,Y (iv) How is Mendeleev's Periodic Table differs from the modern Periodic Table? A Mendeleev's Periodic table does not include noble gases while Modern Periodic table includes them. Mendeleev's Periodic table does not include non-metals while Moderm Periodic table includes them. C Mendeleev's Periodic table does not include halogens while Modern Periodic table includes them. D Mendeleev's Periodic table has only 7 groups while Modern Periodic table has 8 groups. Mendeleev's Periodic table organise elements by increasing atomic number while the Modern Periodic table organise elements by atomic mass. Page 2 of 6 Find this and other free resources at: https://maktaba.tetea.org  Find this and other free resources at: https://maktaba.tetea.org (v) To investigate the solubility of sodium chloride, a technician dissolved different amount of sodium chloride in a specilic volume of water while altering the lemperature of water. \What does temperature represents in this experinent!" A dependent variable B intermediate variable C independent variable D controlled variable E fixcd variable (v) Which property is used to confirm the presence of pure waler? A Itturns white anhydrous copper () sulphate blue B It dissolves all other substances It freezes at 0 °C D It is neutral to litmus paper E It turns blue cobalt ( )chloride paper pink (vii) In which type of oxides does Aluminum oxide belong? A Metaloxides B Insoluble oxides Soluble oxides D Amphoteric oxides E Basic oxides (viii) What is the amount of charge when a current of 2 amperes flows through a certain point in an electrolyte for 0.5 second? A 2coulombs B Icoulombs 2.5 coulombs D 1.5 coulombs 10 coulombs (ix) How can you prevent a hoe from getting rust? A By painting and oiling them. B By exposing them toair. By keeping them in moisture. D By cleaning them with water after use. E By leaving them in the garden after use. (x) When 2.45 g of zinc granules are dropped in 50 cm of acid Y", zinc sulphate is formed along with evolution of gas 'M' which burns with pop sound when kept close to a burning candle. Which one of the following pairs represent the acid Y and gas M? A Sulphuric acid and Carbon dioxide gas. B Sulphuric acid and Hydrogen gas. Hydrochloric acid and Oxygen gas. D Hydrochloric acid and Hydrogen gas. E Sulphuric acid and Oxygen gas. Page 3 of 6 Find this and other free resources at: e 24 https://maktaba.tetea.org  Find this and other free resources at: https://maktaba.tetea.org List B Match the effects of environmental pollution in List A with the respective causes inbooklet answer by writing the letter of the correct response besides the item number in the provided. List A List B (i) Ozone layer depletion A Biological Oxygen Demand (ii) Green House effect BBiomass sludge C Sulphur dioxide (ii) Eutrophication D Chlorine atom (iv) Terrestrial pollution E Liquid effluents F Calcium Ammonium Nitrate (v) Acidic rain G Methane (vi) Water pollution H Ultra Violet Radiation SECTION B (54 Marks) Answer all questions in this section. 3. (a) The products formed when most non-metals burn in oxygen can react with water to form solutions which turn blue litmus paper red. With the aid of chemical equations, show the validity of this statement using carbon as non-metal. (b) (i) Give three properties of oxygen gas. (ii) Give three uses of oxygen gas based on the properties mentioned in (b) (i). 4. (a) Why is Bunsen burner a preferable source of heat in the chemistry laboratory? Give four points. (b) Suggest five sources of heat that can be used in a chemistry laboratory apart from Bunsen burner. 5. (a) Which processes can be used to separate or extract each of the following substances? () Mixture of iodine and sand (ii) Mixture of cooking oil and water (iii) Mixture of sodium chloride and water (iv) Oil from seed (v) Mixture of ethanol and water (vi) Mixture of sand and water (b) Briefly explain application of chromatography process in daily life. Give six points. Page 4 of 6 Find this and other free resources at: https://maktaba.tetea.org  Find this and other free resources at: https://maktaba.tetea.org 6. (a) What are the sources of organic acids? Give five points. (b) ldentify two products which can be formed in each of the following processes: () Reaction of sodium with ethanol. (ii) Partial fermentation of sucrose in presence of yeast cells. 7. (a) Why is it important to replace fossil fuels as an energy source? (b) Briefly explain four alternative sources of energy that can be developed to replace the fossil fuels. 8. (a) How is the conceptof mole useful in Chemistry? Give four points. (b) What mass of impure ammonium chloride (90%) would be needed to react completely with 14.8g of calciumhydroxide? SECTIONC (30 Marks) Answer two (2) questions in this section. 9. (a) The following diagram was used to study the reaction of calcium and water. Gas X Water Calcium Turnings Gas Xproduced was passed through black copper(ll) oxide which changed colour to brown. With the aid of a chemical equation, interpret this observation. (b) Hydrogen atom can react by either gaining or loosing electron. In both cases, energy is involved. With the aid of the chemical equation(s) and energy level diagram, interpret this observation. 10. How is organic manure important to soil quality? Briefly explain by giving five points. Find this and other free resources at: Page 5 of 6 https://maktaba.tetea.org aez024  Find this and other free resources at: https://maktaba.tetea.org Give the explanationon the hydrogen chloride gas based on the following: (a) the raw material for production of the gas. (b) two chemical tests for hydrogen gas. (c) four physical propertics of hydrogen chloride. (d) five uses of hydrogen chloride gas. Find this and other free resources at: Page 6 of6 https://maktaba.tetea.org