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 Which of the following will displace copper from a solution of copper (ll) salt? Silver Zinc ions Aluminium ions Magnesium 2 / 80 Category: CHEMISTRY PAST QUESTIONS The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is sulphur (VI) oxide carbon (IV) oxide hydrogen oxygen 3 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following lowers the activation energy of a chemical reaction? Catalyst Freezing mixture Water Reducing agent 4 / 80 Category: CHEMISTRY PAST QUESTIONS Pauli Exclusion Principle is related to reversiblility of equlibrium reactions collision theory of reaction rates quantum numbers of electrons electronegativity values of elements 5 / 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 metal Neutralisation Double decomposition Action of an acid on a trioxocarbonate (IV) 6 / 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 direct combination is involved and the reaction is endothermic a solid is formed and heat is evolved activation energy is high and a catalyst is required the reaction is endothermic and occurs at high temperature 7 / 80 Category: CHEMISTRY PAST QUESTIONS What does ∆H represent in the following equation ? Cl(g) + e- → CI- (g); ∆H = - 363 kJ mol-1 Electron affinity lonization energy Heat of atomization Dissociation energy 8 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following compounds dissolves in water to form a solution with pH below 7? Potassium hydroxide Ammonium chloride Sodium tetraoxosulphate (VI) Sodium trioxocarbonate (IV) 9 / 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 Magnesium and dilute tetraoxosulphate (VI) acid Water and calcium dicarbide 10 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following substances decomposes when an electric current is passed through it? Tetrachlormethane Hydrochloric acid Zinc rod Glucose solution 11 / 80 Category: CHEMISTRY PAST QUESTIONS Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of emission absorption diffusion combustion 12 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy? 4p 4f 4s 4d 13 / 80 Category: CHEMISTRY PAST QUESTIONS Substances which absorb water from the atmosphere without dissolving in it are said to be hydrated insolube hygroscopic anhydrous 14 / 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 + 15 / 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 only alpha particles and gamma rays beta particles and gamma rays alpha and beta particles 16 / 80 Category: CHEMISTRY PAST QUESTIONS How many electrons are removed from Cr2- when it is oxidized to CrO42-? 0 8 4 2 17 / 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? Q R T S 18 / 80 Category: CHEMISTRY PAST QUESTIONS Metals are said to be malleable because they can be alloyed can be beaten into sheets are good conductors of electricity are good conductors heat 19 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following can undergo both addition reactions and substitution reactions? Hexane Benzene Propene Pentane 20 / 80 Category: CHEMISTRY PAST QUESTIONS Rusting of iron is an example of displacement reaction redox reaction decomposition deliquescence 21 / 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 Graham's law Dalton's law Boyle's law 22 / 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 23 / 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+ CI- H+ OH- 24 / 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 presence of the same number of outermost electrons in the respective atoms presence of the same number of electron shells in the respective atoms difference of +1 in the oxidation numbers of successive members 25 / 80 Category: CHEMISTRY PAST QUESTIONS What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3? Destructive distillation Nutralization Dehydration Redox reaction 26 / 80 Category: CHEMISTRY PAST QUESTIONS The presence of unpaired electrons in an atom of a transition metal gives rise to shiny appearance nalleability ductility paramagnetism 27 / 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 has a higher pH contains more ions has a lower molar mass is neutral to litmus 28 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following properties increases down a group in the Periodic Table? Electon affinity Atomic radius Electronegativity Ionization energy 29 / 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] 101 53 40 122 30 / 80 Category: CHEMISTRY PAST QUESTIONS A mixture of calcium chloride and calcium trioxocarbonate (IV) in water can be separated by evaporation distillation filtration sublimation 31 / 80 Category: CHEMISTRY PAST QUESTIONS What is oxidized in the reaction represented by the following equation? 3CU + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O Copper Oxygen Hydrogen Nitrogen 32 / 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? At equilibrium increase in temperature favours the reverse reaction The reaction goes to completion at equilibrium Pressure has no effect on the equilibrium mixture The forward reaction is exthermic 33 / 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] 8.62dm 3 5.82dm 3 0.896dm 3 0.040dm 3 34 / 80 Category: CHEMISTRY PAST QUESTIONS If the solubility of KHCO3 is 0.40 mole dm-3 100.0g 4.0g 10.0g 40.0g 35 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following would dissolve in warm dilute H2SO4 without effervescence, to give a blue solution? Copper (ll) trioxocarbonate (IV) Copper (ll) oxide Copper turnings Copper alloy 36 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following occurs when a solution of CuSO4 is electrolysed using copper electrodes? The anode increases in mass The cathode becomes coated with copper The blue colour of the solution fades gradually Both electrodes gain electrons 37 / 80 Category: CHEMISTRY PAST QUESTIONS What is the shape of a molecule of CCI4? Linear Tetrahedral Trigonal planar Pyramidal 38 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following features of a human skeleton can be determined by carbon-dating? Race Mass Age Height 39 / 80 Category: CHEMISTRY PAST QUESTIONS Calcium atom ionizes by gaining two protons sharing two electrons losing two electrons gaining two electrons 40 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode? Dilute sodium chloride solution Glucose solution Aqueous copper (ll) tetraoxosulphate (IV) Concentrated hydrochloric acid 41 / 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] 18g 0.318g 6.35g 0.635g 42 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following compounds dissolves in water to give an alkaline solution? Sulphur (IV) oxide Ammonium chloride Sodium chloride Potassium oxide 43 / 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 44 / 80 Category: CHEMISTRY PAST QUESTIONS In the Periodic Table, the elements that loss electrons most readily belong to Group 1 A Group V11 A Group 11 A Group 111 A 45 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following procedures is suitable for identifying the food colouring added to a pastry sample? The anode increases in mass The cathode becomes coated with copper The blue colour of the solution fades gradually Both electrodes gain electrons 46 / 80 Category: CHEMISTRY PAST QUESTIONS The crystal layers in graphite are held together by electrostatic forces covalent bonds hydrogen bonds van der Waals' forces 47 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following increases as boiling water changes to steam? temperature of the system degree of disorder in the system number of molecules activation energy 48 / 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 49 / 80 Category: CHEMISTRY PAST QUESTIONS Helium is preferred to hydrogen in filling balloons because hydrogen is a component of water exhibits isotopy is inflammable is diatomic 50 / 80 Category: CHEMISTRY PAST QUESTIONS Petrol consists mainly of alktanols hydrocarbons alkanoates polymers 51 / 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) Activation energy will decrease the concentration of ammonia will increase the forward reaction will be favoured the reaction will go to completion 52 / 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) Dehydrating agent Acid Bleaching agent Oxidising agent 53 / 80 Category: CHEMISTRY PAST QUESTIONS The property of calcium chloride which makes it useful as a drying agent is that it is a normal salt deliquescent a strong electrolyte ionic 54 / 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 Q is twice as stable as S S decays faster than Q S is more stable than Q 55 / 80 Category: CHEMISTRY PAST QUESTIONS A radioactive solid is best stored in a box lined with lead under paraffin oil under ultraviolet light in a cool, dark cupboard 56 / 80 Category: CHEMISTRY PAST QUESTIONS Equal volumes of CO2 cnd CO at s.t.p have the same mass density rate of diffusion number of molecules 57 / 80 Category: CHEMISTRY PAST QUESTIONS When alkanols react with sodium, the ga evolved is ethyne oxygen methane hydrogen 58 / 80 Category: CHEMISTRY PAST QUESTIONS An exothermic reaction is one which involves loss of heat to the surrounding attainment of dynamic equilibrium positive change in value of enthalpy evolution of gas as it proceeds 59 / 80 Category: CHEMISTRY PAST QUESTIONS Chlorine atom forms CI by Donating lone pair of electrons Sharing one electron Losing one electron Gaining one electron 60 / 80 Category: CHEMISTRY PAST QUESTIONS What is the oxidation number of nitrogen in AI(NO3)3? + 5 + 6 + 1 + 3 61 / 80 Category: CHEMISTRY PAST QUESTIONS What is the value of x in the following equation? Cr2O72- + 14H+ + xe- → 2Cr3+ + 7H2O 8 1 12 6 62 / 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 Shifts equilibrium position to the right Reduces the time for attainment of equilibrium Decreases the value of ∆H Increases the collision rate of reactant particles 63 / 80 Category: CHEMISTRY PAST QUESTIONS It can be concluded that gastric juice has pH value of 7 is acidic contains enzymes is a mixture 64 / 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 the pressure increased a catalysty is intoduced into the system the temperature is raised the volume of the system is increased 65 / 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, ll and lll only l, ll, lll, and IV l and ll only l only 66 / 80 Category: CHEMISTRY PAST QUESTIONS Pipe-borne water is usually chlorinated in order to improve the teste of the water kill harmful bacteria in the water coagulate sediments in the water remove the hardness in the water clear 67 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following contains co-ordinate covalent bond? Na+CI NH4 HCI CH4 68 / 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 25cm cube 35cm cube 30cm cube 50cm cube 69 / 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 dative covalent metallic ionic 70 / 80 Category: CHEMISTRY PAST QUESTIONS Gas molecules are said to be perfectly elastic because they move about in straight lines the distances between them are negligible the volume occupied by them is negligible they collide without loss of energy 71 / 80 Category: CHEMISTRY PAST QUESTIONS Elactrostatic force of attraction between sodium ion and halide ion is greatest in NaI NaCI NaF NaBr 72 / 80 Category: CHEMISTRY PAST QUESTIONS Electrovalent compounds are characterized by high melting point solubility in ethanol strong oxidizing ability high molar mass 73 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following non-metals reacts most readily with metals? Carbon Sulphur Chlorine Nitrogen 74 / 80 Category: CHEMISTRY PAST QUESTIONS Dehydration of ethanol produces ethene ethanal propan-1,2,3-triol ethanoic acid 75 / 80 Category: CHEMISTRY PAST QUESTIONS The liquid product of the destructive distillation of coal is ammoniacal liquor paraffin oil ethanol kerosene 76 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following movements can be described as random motion? wheelbarrow being pushed car travelling on a straight line planets going round the sun gas molecules colliding in a flask 77 / 80 Category: CHEMISTRY PAST QUESTIONS Aluminium is extracted from cassiterite cryolite bauxite magnetite 78 / 80 Category: CHEMISTRY PAST QUESTIONS The type of chemical bond that exists between potassium and oxygen in potassium oxide is metallic dative ionic covalent 79 / 80 Category: CHEMISTRY PAST QUESTIONS Chemical equilibrium is attained when concentrations of the products are greater than those of the reactants reactants stop forming the products reactants in the system are used up concentrations of the reactants and products remain constant 80 / 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 different chemical properties higher molar mass protective oxide coating smaller surface area 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)