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 Chemical equilibrium is attained when concentrations of the reactants and products remain constant concentrations of the products are greater than those of the reactants reactants in the system are used up reactants stop forming the products 2 / 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 Both electrodes gain electrons The blue colour of the solution fades gradually 3 / 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] 0.318g 18g 6.35g 0.635g 4 / 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 5 / 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 element in the free state is zero alkali meta like sodium in its compounds is + 1 monatomic ion is equal to its charge 6 / 80 Category: CHEMISTRY PAST QUESTIONS Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of combustion emission diffusion absorption 7 / 80 Category: CHEMISTRY PAST QUESTIONS Dehydration of ethanol produces propan-1,2,3-triol ethanal ethene ethanoic acid 8 / 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 the temperature is raised the volume of the system is increased a catalysty is intoduced into the system 9 / 80 Category: CHEMISTRY PAST QUESTIONS The spontaneity of a chemical reaction is determined by the change in the concentration of the reactants free energy of the system temperature of the system pressure applied to the system 10 / 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? Pressure has no effect on the equilibrium mixture The forward reaction is exthermic The reaction goes to completion at equilibrium At equilibrium increase in temperature favours the reverse reaction 11 / 80 Category: CHEMISTRY PAST QUESTIONS It can be concluded that gastric juice is acidic contains enzymes is a mixture has pH value of 7 12 / 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 wheelbarrow being pushed planets going round the sun 13 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following non-metals reacts most readily with metals? Sulphur Nitrogen Chlorine Carbon 14 / 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 15 / 80 Category: CHEMISTRY PAST QUESTIONS Pipe-borne water is usually chlorinated in order to coagulate sediments in the water remove the hardness in the water clear improve the teste of the water kill harmful bacteria in the water 16 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following can undergo both addition reactions and substitution reactions? Pentane Propene Benzene Hexane 17 / 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 18 / 80 Category: CHEMISTRY PAST QUESTIONS Aluminium is extracted from bauxite cassiterite magnetite cryolite 19 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following contains co-ordinate covalent bond? CH4 Na+CI HCI NH4 20 / 80 Category: CHEMISTRY PAST QUESTIONS Substances which absorb water from the atmosphere without dissolving in it are said to be hydrated hygroscopic insolube anhydrous 21 / 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? OH- H+ Cu2+ CI- 22 / 80 Category: CHEMISTRY PAST QUESTIONS What is oxidized in the reaction represented by the following equation? 3CU + 8HNO3 → 3Cu(NO3)2 + 2NO + 4H2O Oxygen Hydrogen Copper Nitrogen 23 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy? 4s 4p 4d 4f 24 / 80 Category: CHEMISTRY PAST QUESTIONS Chlorine atom forms CI by Sharing one electron Gaining one electron Losing one electron Donating lone pair of electrons 25 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following compounds dissolves in water to form a solution with pH below 7? Potassium hydroxide Sodium tetraoxosulphate (VI) Sodium trioxocarbonate (IV) Ammonium chloride 26 / 80 Category: CHEMISTRY PAST QUESTIONS Helium is preferred to hydrogen in filling balloons because hydrogen is inflammable exhibits isotopy is a component of water is diatomic 27 / 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 28 / 80 Category: CHEMISTRY PAST QUESTIONS When alkanols react with sodium, the ga evolved is methane oxygen hydrogen ethyne 29 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode? Aqueous copper (ll) tetraoxosulphate (IV) Glucose solution Concentrated hydrochloric acid Dilute sodium chloride solution 30 / 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 the reaction is endothermic and occurs at high temperature a solid is formed and heat is evolved activation energy is high and a catalyst is required 31 / 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 32 / 80 Category: CHEMISTRY PAST QUESTIONS The liquid product of the destructive distillation of coal is ammoniacal liquor ethanol kerosene paraffin oil 33 / 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 reaction will go to completion the forward reaction will be favoured the concentration of ammonia will increase 34 / 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? R S Q T 35 / 80 Category: CHEMISTRY PAST QUESTIONS What is responsible for metallic bonding? Sharing of electrons between the metal atoms Attraction between positive and negative ions transfer of electrons from one atom to another Attraction between the atomic unclei and cloud of electrons 36 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following methods is suitable for the preparation of an insoluble salt? Double decomposition Action of an acid on a trioxocarbonate (IV) Action of an acid on a metal Neutralisation 37 / 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, lll, and IV l and ll only l, ll and lll only 38 / 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 39 / 80 Category: CHEMISTRY PAST QUESTIONS The presence of unpaired electrons in an atom of a transition metal gives rise to nalleability paramagnetism ductility shiny appearance 40 / 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) Acid Oxidising agent Dehydrating agent Bleaching agent 41 / 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 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 difference of 14 atomic mass units between successive members 42 / 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 Reduces the time for attainment of equilibrium Decreases the value of ∆H 43 / 80 Category: CHEMISTRY PAST QUESTIONS Calcium atom ionizes by gaining two protons sharing two electrons gaining two electrons losing two electrons 44 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following pairs of reagents recat to produce hydrogen? Water and calcium dicarbide Copper and dilute hydrochloric acid Zinc and concentrated trioxonitrate (V) acid Magnesium and dilute tetraoxosulphate (VI) acid 45 / 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 25cm cube 30cm cube 46 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following lowers the activation energy of a chemical reaction? Catalyst Freezing mixture Water Reducing agent 47 / 80 Category: CHEMISTRY PAST QUESTIONS Rusting of iron is an example of redox reaction deliquescence displacement reaction decomposition 48 / 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) 49 / 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] 53 40 101 122 50 / 80 Category: CHEMISTRY PAST QUESTIONS Metals are said to be malleable because they are good conductors of electricity can be beaten into sheets can be alloyed are good conductors heat 51 / 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 smaller surface area protective oxide coating 52 / 80 Category: CHEMISTRY PAST QUESTIONS How many electrons are removed from Cr2- when it is oxidized to CrO42-? 4 0 8 2 53 / 80 Category: CHEMISTRY PAST QUESTIONS A mixture of calcium chloride and calcium trioxocarbonate (IV) in water can be separated by sublimation distillation evaporation filtration 54 / 80 Category: CHEMISTRY PAST QUESTIONS In the Periodic Table, the elements that loss electrons most readily belong to Group 11 A Group V11 A Group 111 A Group 1 A 55 / 80 Category: CHEMISTRY PAST QUESTIONS An exothermic reaction is one which involves evolution of gas as it proceeds attainment of dynamic equilibrium positive change in value of enthalpy loss of heat to the surrounding 56 / 80 Category: CHEMISTRY PAST QUESTIONS Elactrostatic force of attraction between sodium ion and halide ion is greatest in NaBr NaF NaCI NaI 57 / 80 Category: CHEMISTRY PAST QUESTIONS Gas molecules are said to be perfectly elastic because they collide without loss of energy they move about in straight lines the volume occupied by them is negligible the distances between them are negligible 58 / 80 Category: CHEMISTRY PAST QUESTIONS Electrovalent compounds are characterized by high molar mass solubility in ethanol strong oxidizing ability high melting point 59 / 80 Category: CHEMISTRY PAST QUESTIONS Petrol consists mainly of alktanols hydrocarbons polymers alkanoates 60 / 80 Category: CHEMISTRY PAST QUESTIONS What does ∆H represent in the following equation ? Cl(g) + e- → CI- (g); ∆H = - 363 kJ mol-1 Dissociation energy Heat of atomization Electron affinity lonization energy 61 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following compounds dissolves in water to give an alkaline solution? Sodium chloride Ammonium chloride Sulphur (IV) oxide Potassium oxide 62 / 80 Category: CHEMISTRY PAST QUESTIONS Equal volumes of CO2 cnd CO at s.t.p have the same rate of diffusion number of molecules mass density 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 is neutral to litmus has a lower molar mass has a higher pH 64 / 80 Category: CHEMISTRY PAST QUESTIONS The type of chemical bond that exists between potassium and oxygen in potassium oxide is covalent ionic metallic dative 65 / 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 deliquescent ionic a normal salt 66 / 80 Category: CHEMISTRY PAST QUESTIONS If the solubility of KHCO3 is 0.40 mole dm-3 40.0g 100.0g 10.0g 4.0g 67 / 80 Category: CHEMISTRY PAST QUESTIONS What is the value of x in the following equation? Cr2O72- + 14H+ + xe- → 2Cr3+ + 7H2O 1 8 6 12 68 / 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 ionic covalent metallic 69 / 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 beta particles and gamma rays alpha and beta particles alpha particles and gamma rays alpha particles only 70 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following procedures is suitable for identifying the food colouring added to a pastry sample? Both electrodes gain electrons The anode increases in mass The blue colour of the solution fades gradually The cathode becomes coated with copper 71 / 80 Category: CHEMISTRY PAST QUESTIONS What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3? Nutralization Redox reaction Destructive distillation Dehydration 72 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following properties increases down a group in the Periodic Table? Electronegativity Electon affinity Atomic radius Ionization energy 73 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following features of a human skeleton can be determined by carbon-dating? Height Mass Race Age 74 / 80 Category: CHEMISTRY PAST QUESTIONS The crystal layers in graphite are held together by van der Waals' forces electrostatic forces hydrogen bonds covalent bonds 75 / 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+ S + P+ → P + S + R + P+ → P + R+ S + Q+ → Q + S+ 76 / 80 Category: CHEMISTRY PAST QUESTIONS What is the shape of a molecule of CCI4? Trigonal planar Pyramidal Tetrahedral Linear 77 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following substances decomposes when an electric current is passed through it? Zinc rod Hydrochloric acid Glucose solution Tetrachlormethane 78 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following will displace copper from a solution of copper (ll) salt? Aluminium ions Magnesium Silver Zinc ions 79 / 80 Category: CHEMISTRY PAST QUESTIONS What is the oxidation number of nitrogen in AI(NO3)3? + 5 + 1 + 3 + 6 80 / 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 Gay-Lussac's Law Graham's law Dalton's law 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)