SS 3 CHEMISTRY PAST QUESTIONS (WAEC/NECO) HomeWAEC/NECO Exam Past QuestionsSS 3 CHEMISTRY PAST QUESTIONS (WAEC/NECO) 0% SSCE/NECO/GCE (CHEMISTRY PAST QUESTIONS) CHEMISTRY PAST QUESTIONS APP Questions will be picked at random from the question bank. You can use the NEXT button to move to the next question, use the PREV button to move to the previous question, the CLEAR button to clear any answer of your choice and you have the FINISH button to end the exam if you choose to. Any question not answered before the end of the exam time, will be marked as wrong and the exam will end by itself. so try to attempt all questions on time. Goodluck! 1 / 80 Category: CHEMISTRY PAST QUESTIONS Aluminium is extracted from cassiterite magnetite bauxite cryolite 2 / 80 Category: CHEMISTRY PAST QUESTIONS The atoms of four elements are represented as 20Q, 16R, 10S and 8T Which of the elements would be unreactive? T S R Q 3 / 80 Category: CHEMISTRY PAST QUESTIONS What does ∆H represent in the following equation ? Cl(g) + e- → CI- (g); ∆H = - 363 kJ mol-1 lonization energy Dissociation energy Heat of atomization Electron affinity 4 / 80 Category: CHEMISTRY PAST QUESTIONS What is the oxidation number of nitrogen in AI(NO3)3? + 6 + 3 + 1 + 5 5 / 80 Category: CHEMISTRY PAST QUESTIONS The spontaneity of a chemical reaction is determined by the change in the temperature of the system free energy of the system concentration of the reactants pressure applied to the system 6 / 80 Category: CHEMISTRY PAST QUESTIONS Substances which absorb water from the atmosphere without dissolving in it are said to be insolube anhydrous hydrated hygroscopic 7 / 80 Category: CHEMISTRY PAST QUESTIONS Consider the reaction represented by the following equation: H2(g) + 12(g) → 2HI(g). The number of effective collisions of molecules of the reactants decreases as a catalysty is intoduced into the system the pressure increased the temperature is raised the volume of the system is increased 8 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following non-metals reacts most readily with metals? Nitrogen Sulphur Chlorine Carbon 9 / 80 Category: CHEMISTRY PAST QUESTIONS Chlorine atom forms CI by Losing one electron Gaining one electron Donating lone pair of electrons Sharing one electron 10 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following is not correct about oxidation number convention? The oxidation number of a/an atom of a diatomic molecules is + 2 alkali meta like sodium in its compounds is + 1 element in the free state is zero monatomic ion is equal to its charge 11 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following procedures is suitable for identifying the food colouring added to a pastry sample? The blue colour of the solution fades gradually Both electrodes gain electrons The anode increases in mass The cathode becomes coated with copper 12 / 80 Category: CHEMISTRY PAST QUESTIONS What is the effect of using vanadium (V) oxide as catalyst in the reaction represented by the following equation? 2SO2 + O2 ⇌ 2SO3; ∆H = - xKJmol-1 Reduces the time for attainment of equilibrium Increases the collision rate of reactant particles Decreases the value of ∆H Shifts equilibrium position to the right 13 / 80 Category: CHEMISTRY PAST QUESTIONS How many electrons are removed from Cr2- when it is oxidized to CrO42-? 2 8 0 4 14 / 80 Category: CHEMISTRY PAST QUESTIONS A finely divided from of a metal burns more readily in air than the rod from because the rod has protective oxide coating different chemical properties higher molar mass smaller surface area 15 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following lowers the activation energy of a chemical reaction? Freezing mixture Catalyst Water Reducing agent 16 / 80 Category: CHEMISTRY PAST QUESTIONS A mixture of calcium chloride and calcium trioxocarbonate (IV) in water can be separated by filtration sublimation distillation evaporation 17 / 80 Category: CHEMISTRY PAST QUESTIONS What is the function of sulphur (IV) oxide in the reaction represented by the following equation? SO 2(aq) + 2H2S(g) → 3S (s) + 2H 2O (l) Bleaching agent Dehydrating agent Acid Oxidising agent 18 / 80 Category: CHEMISTRY PAST QUESTIONS A sheet of paper is placed in the path of a beam from a radioactive source. The emissions that pass through the paper consist of alpha particles and gamma rays alpha and beta particles beta particles and gamma rays alpha particles only 19 / 80 Category: CHEMISTRY PAST QUESTIONS The property of calcium chloride which makes it useful as a drying agent is that it is a strong electrolyte a normal salt deliquescent ionic 20 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following movements can be described as random motion? gas molecules colliding in a flask car travelling on a straight line planets going round the sun wheelbarrow being pushed 21 / 80 Category: CHEMISTRY PAST QUESTIONS Rusting of iron is an example of deliquescence displacement reaction decomposition redox reaction 22 / 80 Category: CHEMISTRY PAST QUESTIONS If an element with high electron affinity combines with another element with low ionization energy the bond formed will be mainly ionic covalent metallic dative 23 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following would dissolve in warm dilute H2SO4 without effervescence, to give a blue solution? Copper alloy Copper (ll) oxide Copper turnings Copper (ll) trioxocarbonate (IV) 24 / 80 Category: CHEMISTRY PAST QUESTIONS What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn(s) + 2HCI(aq) → ZnCI 2(aq) + H2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm3 at s.t.p] 0.040dm 3 8.62dm 3 5.82dm 3 0.896dm 3 25 / 80 Category: CHEMISTRY PAST QUESTIONS Elactrostatic force of attraction between sodium ion and halide ion is greatest in NaBr NaF NaCI NaI 26 / 80 Category: CHEMISTRY PAST QUESTIONS If the solubility of KHCO3 is 0.40 mole dm-3 10.0g 4.0g 100.0g 40.0g 27 / 80 Category: CHEMISTRY PAST QUESTIONS Metals are said to be malleable because they can be beaten into sheets are good conductors heat can be alloyed are good conductors of electricity 28 / 80 Category: CHEMISTRY PAST QUESTIONS What is oxidized in the reaction represented by the following equation? 3CU + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O Oxygen Copper Hydrogen Nitrogen 29 / 80 Category: CHEMISTRY PAST QUESTIONS In the Periodic Table, the elements that loss electrons most readily belong to Group 1 A Group 111 A Group 11 A Group V11 A 30 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following features of a human skeleton can be determined by carbon-dating? Age Height Mass Race 31 / 80 Category: CHEMISTRY PAST QUESTIONS The crystal layers in graphite are held together by hydrogen bonds van der Waals' forces electrostatic forces covalent bonds 32 / 80 Category: CHEMISTRY PAST QUESTIONS The presence of unpaired electrons in an atom of a transition metal gives rise to ductility nalleability paramagnetism shiny appearance 33 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following pairs of reagents recat to produce hydrogen? Copper and dilute hydrochloric acid Zinc and concentrated trioxonitrate (V) acid Water and calcium dicarbide Magnesium and dilute tetraoxosulphate (VI) acid 34 / 80 Category: CHEMISTRY PAST QUESTIONS What is the value of x in the following equation? Cr2O72- + 14H+ + xe- → 2Cr3+ + 7H2O 12 8 6 1 35 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following can undergo both addition reactions and substitution reactions? Propene Hexane Pentane Benzene 36 / 80 Category: CHEMISTRY PAST QUESTIONS What mass of copper would be deposited by a current of 1. 0 ampere passing for 965 seconds through copper (ll) tetraoxosulphate (IV) solution? [Cu = 63.5; 1F = 96500C] 0.635g 0.318g 18g 6.35g 37 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following compounds dissolves in water to give an alkaline solution? Sulphur (IV) oxide Potassium oxide Sodium chloride Ammonium chloride 38 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following increases as boiling water changes to steam? number of molecules activation energy temperature of the system degree of disorder in the system 39 / 80 Category: CHEMISTRY PAST QUESTIONS What is responsible for metallic bonding? Attraction between positive and negative ions transfer of electrons from one atom to another Sharing of electrons between the metal atoms Attraction between the atomic unclei and cloud of electrons 40 / 80 Category: CHEMISTRY PAST QUESTIONS What will be the effect of increase in pressure on the following system at equilibrium? 2NH2(g) N2(g) + 3H2(g) the reaction will go to completion the forward reaction will be favoured the concentration of ammonia will increase Activation energy will decrease 41 / 80 Category: CHEMISTRY PAST QUESTIONS Pipe-borne water is usually chlorinated in order to coagulate sediments in the water improve the teste of the water remove the hardness in the water clear kill harmful bacteria in the water 42 / 80 Category: CHEMISTRY PAST QUESTIONS Consider the following equation: Ag+ (aq) + CI-(aq) → Ag+CI- (s) ; ∆H = _65.7 kJmol-1. From the equation, it can be deduced that a solid is formed and heat is evolved direct combination is involved and the reaction is endothermic the reaction is endothermic and occurs at high temperature activation energy is high and a catalyst is required 43 / 80 Category: CHEMISTRY PAST QUESTIONS Gas molecules are said to be perfectly elastic because the distances between them are negligible the volume occupied by them is negligible they move about in straight lines they collide without loss of energy 44 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following occurs when a solution of CuSO4 is electrolysed using copper electrodes? The cathode becomes coated with copper Both electrodes gain electrons The blue colour of the solution fades gradually The anode increases in mass 45 / 80 Category: CHEMISTRY PAST QUESTIONS Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of emission absorption diffusion combustion 46 / 80 Category: CHEMISTRY PAST QUESTIONS What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3? Redox reaction Dehydration Nutralization Destructive distillation 47 / 80 Category: CHEMISTRY PAST QUESTIONS It can be concluded that gastric juice contains enzymes is acidic has pH value of 7 is a mixture 48 / 80 Category: CHEMISTRY PAST QUESTIONS 30cm3 pf hydrogen at s.t.p combine with 20cm3 of oxygen to form steam according to the following equation 2H2(g) + O2(g) → 2H2O(g). Calculate the total volume of the gaseous mixture at the end of the reaction 30cm cube 25cm cube 35cm cube 50cm cube 49 / 80 Category: CHEMISTRY PAST QUESTIONS P Total = F1 + P2 + P 3 + .........Pn' where P Total is the pressure of a mixture of gasses. The equation above is an expression of Gay-Lussac's Law Boyle's law Dalton's law Graham's law 50 / 80 Category: CHEMISTRY PAST QUESTIONS The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is hydrogen carbon (IV) oxide oxygen sulphur (VI) oxide 51 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following statements about ideal gases is/are correct? I. The cohesive forces between their particles are negligible ll. The have no definite volume but occupy the volume of their containers III. They are not compressible IV. Their particles collide with loss of energy l only l, ll and lll only l, ll, lll, and IV l and ll only 52 / 80 Category: CHEMISTRY PAST QUESTIONS What is the shape of a molecule of CCI4? Linear Pyramidal Tetrahedral Trigonal planar 53 / 80 Category: CHEMISTRY PAST QUESTIONS A reaction is represented by the equation below. A2(g) + B2(g) 2AB(g); ∆H = +X kJmol-1 Which of the following statements about the system is correct? The forward reaction is exthermic The reaction goes to completion at equilibrium At equilibrium increase in temperature favours the reverse reaction Pressure has no effect on the equilibrium mixture 54 / 80 Category: CHEMISTRY PAST QUESTIONS A radioactive solid is best stored in a cool, dark cupboard in a box lined with lead under paraffin oil under ultraviolet light 55 / 80 Category: CHEMISTRY PAST QUESTIONS The type of chemical bond that exists between potassium and oxygen in potassium oxide is covalent dative metallic ionic 56 / 80 Category: CHEMISTRY PAST QUESTIONS Dehydration of ethanol produces ethanoic acid propan-1,2,3-triol ethene ethanal 57 / 80 Category: CHEMISTRY PAST QUESTIONS Given that the order of reactivity of four metals is P>Q>R>S, which of the following reactions is feasible? Q + S+ → S + Q+ R + P+ → P + R+ S + Q+ → Q + S+ S + P+ → P + S + 58 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following contains co-ordinate covalent bond? Na+CI CH4 HCI NH4 59 / 80 Category: CHEMISTRY PAST QUESTIONS One mole of a compound M(HCO3)2 has a mass of 162g. Calculate the relative atomic mass of M. [H = 1, C =12, O = 16] 40 122 101 53 60 / 80 Category: CHEMISTRY PAST QUESTIONS Calcium atom ionizes by gaining two protons gaining two electrons sharing two electrons losing two electrons 61 / 80 Category: CHEMISTRY PAST QUESTIONS Helium is preferred to hydrogen in filling balloons because hydrogen exhibits isotopy is inflammable is diatomic is a component of water 62 / 80 Category: CHEMISTRY PAST QUESTIONS Petrol consists mainly of alkanoates polymers hydrocarbons alktanols 63 / 80 Category: CHEMISTRY PAST QUESTIONS 0.10 mol dm-3 NaCI conducts electricity better than 0.10 mol dm-3 CH3COOH because the solution of NaCI contains more ions has a lower molar mass is neutral to litmus has a higher pH 64 / 80 Category: CHEMISTRY PAST QUESTIONS When alkanols react with sodium, the ga evolved is hydrogen oxygen ethyne methane 65 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following compounds dissolves in water to form a solution with pH below 7? Potassium hydroxide Sodium trioxocarbonate (IV) Ammonium chloride Sodium tetraoxosulphate (VI) 66 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following substances decomposes when an electric current is passed through it? Tetrachlormethane Glucose solution Hydrochloric acid Zinc rod 67 / 80 Category: CHEMISTRY PAST QUESTIONS Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore Q emits fewer particles than S S decays faster than Q Q is twice as stable as S S is more stable than Q 68 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following properties increases down a group in the Periodic Table? Electon affinity Electronegativity Ionization energy Atomic radius 69 / 80 Category: CHEMISTRY PAST QUESTIONS An exothermic reaction is one which involves attainment of dynamic equilibrium positive change in value of enthalpy loss of heat to the surrounding evolution of gas as it proceeds 70 / 80 Category: CHEMISTRY PAST QUESTIONS The liquid product of the destructive distillation of coal is kerosene ethanol paraffin oil ammoniacal liquor 71 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following will displace copper from a solution of copper (ll) salt? Silver Magnesium Zinc ions Aluminium ions 72 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy? 4p 4d 4f 4s 73 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following methods is suitable for the preparation of an insoluble salt? Action of an acid on a trioxocarbonate (IV) Action of an acid on a metal Neutralisation Double decomposition 74 / 80 Category: CHEMISTRY PAST QUESTIONS Pauli Exclusion Principle is related to reversiblility of equlibrium reactions electronegativity values of elements collision theory of reaction rates quantum numbers of electrons 75 / 80 Category: CHEMISTRY PAST QUESTIONS Elements which belong to the same group in the Periodic Table are characterized by difference of 14 atomic mass units between successive members difference of +1 in the oxidation numbers of successive members presence of the same number of outermost electrons in the respective atoms presence of the same number of electron shells in the respective atoms 76 / 80 Category: CHEMISTRY PAST QUESTIONS A concentrated solution containing H+, Cu2+,OH- and CI- was electrolysed using platiunm electrodes which of the ions will be discharged at the cathods? Cu2+ H+ CI- OH- 77 / 80 Category: CHEMISTRY PAST QUESTIONS Electrovalent compounds are characterized by high melting point strong oxidizing ability high molar mass solubility in ethanol 78 / 80 Category: CHEMISTRY PAST QUESTIONS Chemical equilibrium is attained when reactants stop forming the products concentrations of the products are greater than those of the reactants concentrations of the reactants and products remain constant reactants in the system are used up 79 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode? Concentrated hydrochloric acid Aqueous copper (ll) tetraoxosulphate (IV) Dilute sodium chloride solution Glucose solution 80 / 80 Category: CHEMISTRY PAST QUESTIONS Equal volumes of CO2 cnd CO at s.t.p have the same mass rate of diffusion density number of molecules Your score is 0% Restart quiz Practice also: SS 3 BIOLOGY PAST QUESTIONS (WAEC/NECO) SS 3 AGRIC SCIENCE PAST QUESTIONS (WAEC/NECO) SS 3 COMPUTER STUDIES PAST QUESTIONS (WAEC/NECO) SS 3 COMMERCE PAST QUESTIONS (WAEC/NECO) SS 3 DATA PROCESSING PAST QUESTIONS (WAEC/NECO)