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 Pauli Exclusion Principle is related to electronegativity values of elements quantum numbers of electrons reversiblility of equlibrium reactions collision theory of reaction rates 2 / 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 3 / 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 4 / 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 S is more stable than Q Q is twice as stable as S 5 / 80 Category: CHEMISTRY PAST QUESTIONS If the solubility of KHCO3 is 0.40 mole dm-3 4.0g 100.0g 40.0g 10.0g 6 / 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 pressure increased the volume of the system is increased 7 / 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 8 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following properties increases down a group in the Periodic Table? Electon affinity Ionization energy Atomic radius Electronegativity 9 / 80 Category: CHEMISTRY PAST QUESTIONS Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of absorption combustion diffusion emission 10 / 80 Category: CHEMISTRY PAST QUESTIONS The spontaneity of a chemical reaction is determined by the change in the concentration of the reactants temperature of the system pressure applied to the system free energy of the system 11 / 80 Category: CHEMISTRY PAST QUESTIONS Elactrostatic force of attraction between sodium ion and halide ion is greatest in NaF NaCI NaI NaBr 12 / 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 0.040dm 3 0.896dm 3 5.82dm 3 13 / 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 14 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following movements can be described as random motion? car travelling on a straight line gas molecules colliding in a flask planets going round the sun wheelbarrow being pushed 15 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following methods is suitable for the preparation of an insoluble salt? Neutralisation Action of an acid on a trioxocarbonate (IV) Double decomposition Action of an acid on a metal 16 / 80 Category: CHEMISTRY PAST QUESTIONS Dehydration of ethanol produces ethanoic acid ethene ethanal propan-1,2,3-triol 17 / 80 Category: CHEMISTRY PAST QUESTIONS In the Periodic Table, the elements that loss electrons most readily belong to Group V11 A Group 11 A Group 111 A Group 1 A 18 / 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 only l and ll only l, ll, lll, and IV 19 / 80 Category: CHEMISTRY PAST QUESTIONS The crystal layers in graphite are held together by hydrogen bonds covalent bonds van der Waals' forces electrostatic forces 20 / 80 Category: CHEMISTRY PAST QUESTIONS Metals are said to be malleable because they are good conductors of electricity can be alloyed are good conductors heat can be beaten into sheets 21 / 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 22 / 80 Category: CHEMISTRY PAST QUESTIONS Electrovalent compounds are characterized by solubility in ethanol high melting point strong oxidizing ability high molar mass 23 / 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 24 / 80 Category: CHEMISTRY PAST QUESTIONS How many electrons are removed from Cr2- when it is oxidized to CrO42-? 2 8 4 0 25 / 80 Category: CHEMISTRY PAST QUESTIONS Chemical equilibrium is attained when reactants stop forming the products 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 26 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following would dissolve in warm dilute H2SO4 without effervescence, to give a blue solution? Copper (ll) oxide Copper alloy Copper turnings Copper (ll) trioxocarbonate (IV) 27 / 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 The blue colour of the solution fades gradually Both electrodes gain electrons The anode increases in mass 28 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following can undergo both addition reactions and substitution reactions? Propene Hexane Pentane Benzene 29 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following is not correct about oxidation number convention? The oxidation number of a/an alkali meta like sodium in its compounds is + 1 monatomic ion is equal to its charge element in the free state is zero atom of a diatomic molecules is + 2 30 / 80 Category: CHEMISTRY PAST QUESTIONS A radioactive solid is best stored under paraffin oil under ultraviolet light in a cool, dark cupboard in a box lined with lead 31 / 80 Category: CHEMISTRY PAST QUESTIONS Pipe-borne water is usually chlorinated in order to kill harmful bacteria in the water coagulate sediments in the water improve the teste of the water remove the hardness in the water clear 32 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode? Dilute sodium chloride solution Concentrated hydrochloric acid Glucose solution Aqueous copper (ll) tetraoxosulphate (IV) 33 / 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 34 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following increases as boiling water changes to steam? degree of disorder in the system number of molecules activation energy temperature of the system 35 / 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 Heat of atomization lonization energy Dissociation energy 36 / 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 contains more ions has a higher pH 37 / 80 Category: CHEMISTRY PAST QUESTIONS An exothermic reaction is one which involves positive change in value of enthalpy attainment of dynamic equilibrium evolution of gas as it proceeds loss of heat to the surrounding 38 / 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 Oxidising agent Dehydrating agent Acid 39 / 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? H+ CI- Cu2+ OH- 40 / 80 Category: CHEMISTRY PAST QUESTIONS The liquid product of the destructive distillation of coal is paraffin oil kerosene ammoniacal liquor ethanol 41 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following features of a human skeleton can be determined by carbon-dating? Age Height Race Mass 42 / 80 Category: CHEMISTRY PAST QUESTIONS The presence of unpaired electrons in an atom of a transition metal gives rise to shiny appearance paramagnetism nalleability ductility 43 / 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 44 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following lowers the activation energy of a chemical reaction? Catalyst Reducing agent Freezing mixture Water 45 / 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 46 / 80 Category: CHEMISTRY PAST QUESTIONS Calcium atom ionizes by sharing two electrons gaining two protons losing two electrons gaining two electrons 47 / 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 48 / 80 Category: CHEMISTRY PAST QUESTIONS Petrol consists mainly of hydrocarbons polymers alktanols alkanoates 49 / 80 Category: CHEMISTRY PAST QUESTIONS Aluminium is extracted from magnetite cassiterite bauxite cryolite 50 / 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 concentration of ammonia will increase the reaction will go to completion Activation energy will decrease the forward reaction will be favoured 51 / 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 metallic covalent ionic 52 / 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 activation energy is high and a catalyst is required a solid is formed and heat is evolved the reaction is endothermic and occurs at high temperature direct combination is involved and the reaction is endothermic 53 / 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) 54 / 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 18g 0.635g 0.318g 55 / 80 Category: CHEMISTRY PAST QUESTIONS Chlorine atom forms CI by Gaining one electron Losing one electron Sharing one electron Donating lone pair of electrons 56 / 80 Category: CHEMISTRY PAST QUESTIONS Substances which absorb water from the atmosphere without dissolving in it are said to be hydrated hygroscopic anhydrous insolube 57 / 80 Category: CHEMISTRY PAST QUESTIONS What is the shape of a molecule of CCI4? Linear Trigonal planar Pyramidal Tetrahedral 58 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following non-metals reacts most readily with metals? Nitrogen Sulphur Carbon Chlorine 59 / 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 T S Q 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 beta particles and gamma rays alpha and beta particles alpha particles only 61 / 80 Category: CHEMISTRY PAST QUESTIONS The type of chemical bond that exists between potassium and oxygen in potassium oxide is covalent metallic ionic dative 62 / 80 Category: CHEMISTRY PAST QUESTIONS What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO3? Nutralization Dehydration Redox reaction Destructive distillation 63 / 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 + P+ → P + S + S + Q+ → Q + S+ R + P+ → P + R+ Q + S+ → S + Q+ 64 / 80 Category: CHEMISTRY PAST QUESTIONS Elements which belong to the same group in the Periodic Table are characterized by difference of +1 in the oxidation numbers of successive members 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 65 / 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 66 / 80 Category: CHEMISTRY PAST QUESTIONS Rusting of iron is an example of displacement reaction decomposition deliquescence redox reaction 67 / 80 Category: CHEMISTRY PAST QUESTIONS The gas evolved when dilute tetraoxosulphate (VI) acid reacts with sodium hydrogen trioxocarbonate (IV) is oxygen sulphur (VI) oxide carbon (IV) oxide hydrogen 68 / 80 Category: CHEMISTRY PAST QUESTIONS What is the value of x in the following equation? Cr2O72- + 14H+ + xe- → 2Cr3+ + 7H2O 8 1 12 6 69 / 80 Category: CHEMISTRY PAST QUESTIONS A mixture of calcium chloride and calcium trioxocarbonate (IV) in water can be separated by distillation evaporation sublimation filtration 70 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following substances decomposes when an electric current is passed through it? Glucose solution Zinc rod Hydrochloric acid Tetrachlormethane 71 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy? 4f 4p 4s 4d 72 / 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 Decreases the value of ∆H Reduces the time for attainment of equilibrium Increases the collision rate of reactant particles 73 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following compounds dissolves in water to give an alkaline solution? Sulphur (IV) oxide Sodium chloride Ammonium chloride Potassium oxide 74 / 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 higher molar mass protective oxide coating smaller surface area different chemical properties 75 / 80 Category: CHEMISTRY PAST QUESTIONS Which of the following contains co-ordinate covalent bond? HCI Na+CI NH4 CH4 76 / 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 Both electrodes gain electrons The cathode becomes coated with copper 77 / 80 Category: CHEMISTRY PAST QUESTIONS When alkanols react with sodium, the ga evolved is hydrogen methane oxygen ethyne 78 / 80 Category: CHEMISTRY PAST QUESTIONS What is the oxidation number of nitrogen in AI(NO3)3? + 5 + 1 + 3 + 6 79 / 80 Category: CHEMISTRY PAST QUESTIONS It can be concluded that gastric juice has pH value of 7 contains enzymes is acidic is a mixture 80 / 80 Category: CHEMISTRY PAST QUESTIONS The property of calcium chloride which makes it useful as a drying agent is that it is ionic a normal salt a strong electrolyte deliquescent 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)