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