Chemistry Exam Questions for Senior school students (Class III)

Chemistry Exam Questions for Senior school students (Class III)

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

1. 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

2. 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

3. 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

1. 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

2. 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

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

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

5. 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

6. 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

7. 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

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

9. 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

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

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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

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

19. Which of the following is an ore of aluminum? A. Haematite B. Magnetite C. Siderite D. Bauxite

20. 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.

21. 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

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

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

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

25. 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

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

27. 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

28. 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

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

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

That is all for now