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