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