Chemistry Exam Questions for Senior school students– Chemistry is the study of the composition,properties,nature and uses of matters. It deals with the study of chemical reactions.

Matter is anything that ha weight and occupy spaces. There are three states of matter, such as solid, liquid and gases. Matter undergoes changes which can be physical change in which no new substance is been formed or chemical change in which a new substance is formed and its not easily reversible. Example of chemical changes include iron rust and burning of substances in air.

This page contains Chemistry Examination questions for senior school students (Class III)

1. The atoms of four elements are represented as 20Q, 16R, 10S and 8T. which of the elements would be unreactive A. Q B. R C. S D. T

2. The type of chemical bond that exists between potassium and oxygen in potassium oxide is A. Ionic B. Metallic C. Covalent D. Dative

3. Chlorine atom forms Cl- by A. Losing one electron B. Sharing one electron C. Donating one pair of electrons D. Gaining one electron

4.An element Z has a combining power of 3. Which of the following formulae is correct of its compound A. ZSO3 B. Z3Cl2 C. Z2O3 D. ZS3

5.The gas evolved when dilute tetraoxosulphate(iv) acid reacts with sodium hydrogentrioxocarbonate(iv) is A. Hydrogen B. Oxygen
C. Carbon(iv)oxide D. Sulphur(vi)oxide

6. If a solution has a pH of 2, it can be concluded that it A. Is a weak electrolyte B. has hydrogen concentration of 0.2moldm-3 C. Is twice as acidic as a solution of pH, D. Will produce effervescence with magnesium ribbon

7. Chemical equilibrium is attained when A. Reactants in the system are used up B. Concentrations of the products are greater than those of the reactants C. Concentrations of the reactants and products remain constant D. reactants stop forming the products

8. An iron nail placed in a solution of copper(ii)tetraoxosulphate(vi) is soon covered with a deposit of copper. Which of the following equations represents the reaction?
A. Fe2+(aq) + Cu(s) Fe3+(aq)
B. Fe2+(aq) + Cu(s) Fe(s) + Cu2+(aq)
C. Fe(s) + Cu2+(aq) Fe2+(aq) + Cu2+(aq)
D. Fe(s) + Cu2+(aq) Fe2+(aq)

9.Which of the following non-metals reacts most readily with metals? A. Nitrogen B. Chlorine C. Sulphur D. Carbon

10. A radioactive substance is best stored A. Under paraffin oil B. Under ultravidet light C. In a cool, dark cupboard D. In a box lined with lead

11. In the electrolytic extraction of aluminum from puried alumina; molten cryolite is added in order to A. lower the melting point of the alumina B. Prevent the aerial oxidation of the molten aluminum C. Lower the activation energy of the reaction D. Form a protective crust on top of the electrolyte

11. When iron rusts, it undergoes A. Deliquescence B. Chemical decomposition C. Hydrolysis D. Redox reaction

12. Which of the following involves the decomposition of a sugar by enzymic action? A. Esterification B. Fermentation C. Dehydration D. Polymerization

13. If a reaction is said to be exothermic, which of the following statements is a correct deduction from the information? A. The reaction vessel gets hotter as the reaction proceeds B. ∆H for the reaction is positive C. The rate of the reaction increases with time D. The activation energy of the reaction is high

14. A dye s suspected to have contaminated a lollipop. Which of the following is the best method by which the contaminant may be isolated?
A. Fractional distillation B. Recrystallization C. Filtration D. Paper Chromatography

15. Which of the following accounts for the difference in the mode of conduction of electricity by metals and aqueous salt solutions? A. Electrons are present in metals but not in salt solutions B. Metals are conducted while salts are electrolytes C. Electricity is carried by mobile electrons in metals but by ions in aqueous salt solution D. Salts ionize in aqueous solutions

16. while metals do not.A positive brown ring test indicates the presence of A. NO-3¬ B. Fe3+ C. 〖SO〗_3^(2-) D. Cu+

17. The following statements about graphite are correct EXCEPT that it A. Is used as a lubricant B. Has a network structure C. Contains mobile free electrons D. Is a good conductor
Which of the following hydrocarbons is unsaturated? A. Ethane B. Benzene C. Propane D. Z-methylbutane

18. Which of the following is an alloy of mercury? A. Stainless steel B. Soft solder C. Coinage bronze D. Amalgam

19. Metals which react with steam only when they are red-hot include A. Copper B. Sodium C. Calcium D. Iron

20. An arrangement of two different metals in aqueous solutions of their salts to produce an electric current is known as A. Electrochemical cell B. Activity series C. Thermocouple D. Volmeter

21. Which of the following exhibits resonance? A. Benzene B. Butane C. Pentene D. Octane
Which of the following metals will be the most suitable for use where lightness and resistance to corrosion are of important? A. Lead B. Copper C. Iron D. Aluminum

22. What is the most probable group of an element which is a soft, silvery-white solid and reacts violently with water? A. Group O B. Group 1 C. Group 4 D. Group 6

23. Which of the following ions will migrate to the cathode during electrolysis? A. Zinc ions B. Chloride ions C. Suphide ions D. Tetraoxosulphate(vi)ions

24. Which of the following radioactive decays involve an ∝-β emission?
A. (_92^238)U →(_90^234)Th +(_2^4)He B. (_80^238)Hg →(_81^238)Tl C. (_50^199)Sn →(_50^199)Sn
D. (_1^2)H+ (_1^2)H →(_1^3)H + (_1^1)H

25. The following oxides react with both acids and bases to form salts except A. Zinc oxide B. Lead (ii) oxide C. Aluminium oxide D. Carbon(iv)oxide

26. Which of the following metals is NOT extracted by electrolysis? A. Iron B. Sodium C. Calcium D. Magnesium

27. Which of the following is an ore of aluminum? A. Haematite B. Magnetite C. Siderite D. Bauxite
28. Which of the following statements is/are correct about metals? They I. Are good conductors of electricity II. Have mobile electrons III are reducing agent IV. Form acidic oxides A. I and II only B. I, II and III only C. I, II, III and IV D. None of the above.

29. The main type of reaction that occurs in the blast furnace during the extraction of Iron is A. reduction reaction B. Decomposition C. Exothermic reaction D. Combustion

30. Which of the following compounds can be represented by the molecule formula C2H6O A. Propanal B. Ethanol C. Methanoic acid D. Glucose

31. The following compounds are hydrocarbons EXCEPT A. Methylpropanoate B. Z-methylbutane C. Benzene D. Cyclohexane

32. When alkynes are hydrogenated completely, they produce compounds with the general molecular formula A. CnHn B. CnH2n+2 C. CnH2n D. CnH2n-2

33. Which of the following alloys does not contain copper? I. Brass II. Bronze III. Steel A. I only B. II only C. III only D. II and III only

34. The major product in the solvay process is A. NaOH B. Na2CO3 C. NH3 D. H2SO4

35. 100g of radioactive mass has a half-life of 5 days. Calculate the mass decayed off after 15 days. A. 25g B. 50g C. 12.5g D. 6.25g

36. A solution of sodium trioxocarbonate(iv) contains 10.6g in 250cm3 of solution. Calculate the concentration of the solution. A. 0.4moldm-3 B. 1.0moldm-3 C. 10.6moldm-3 D. 25.0moldm-3

37.What mass of copper would be formed when a current of 10.0A is passed through a solution of CuSO4 for 1hour? A. 5.9g B.11.8g C. 23.7g D. 47.3g

38 The volume occupied by 0.4¬¬g of hydrogen gas at S.t.p is A.2.2dm3
B. 4.48dm3 C. 22.4dm3 D. 44.8dm3

39. The oxidation number of Fe in [Fe(CN)6]3- is A. +3 B. +2 C. -2 D. -3

40. Reduction is the process of A. Loss of electron Loss of hydrogen C. loss of oxygen  D. Addition of electronegative elements.

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