JAMB CHEMISTRY PAST QUESTIONS 1)Chromatography is used to *How can I create components of mixtures which differ in their rates of? A. diffusion B. migration C. reaction D. sedimentaion 2)Which of the following is a example of a chemical change? A. Dissoultion of salt in water B. Rusting of iron C. Melting of ice D. Separating a mixture by distillation 3)The number of hydrogen ions in 4.9 g of tetraoxosulphate (IV) acid is? (S = 32, O =16, H = 1, Na = 6.02 x 1023 A. 3.01 x 1022 B. 6.02 x 1022 C. 3.01 x 1023 D. 6.01 x 1023 4)What volume of oxygen will remain after reacting 8cm3 of hydrogen with 20cm3 of oxygen? A. 10 cm3 B. 12 cm3 C. 14 cm3 D. 16 cm3 5)A gas sample with an initial volume of 3.25 dm3 is heated and allowed to expand to 9.75 dm3 at constant pressure. What is the ratio of the final absolute temperature to the initial absolute temperature? A. 3:1 B. 5:2 C. 5:4 D. 8:3 6)Two cylinders A and B each contains 30 cm3 of oxygen and nitrogen respectively at the same temperature and pressure. If there are 5.0 moles of nitrogen, then the mass of oxygen is? A. 3.2 g B. 6.4 g C. 80.0 g D. 160.0 g 7)A liquid begins to boil when? A. its vapour pressure is equal to the vapour pressure of its solid at the given temperature B. molecules start escaping from its surface C. its vapour pressure equals the atmosphere pressure D. its volume is sightly increased 8)A particle that contains 8 proton, 9 neutrons and 7 electrons could be written as? A. O B. O+ C. N D. O- 9)In the oil drop experiment, Millikan determined the? A. charge to mass ratio of the electron B. mass of the electron C. charge of the electron D. mass of the proton 10)The ability of ionic solids is generally due to the? A. negative electron affinity of most atoms B. crystal lattice forces C. electron pair sharing D. positive ionization potentials 11)Which of the following statements is FALSE about isotopes of the same element? A. They have the same number of electrons in their outermost shells B. They have different atomic masses C. They have the same atomic number and the number of electrons D. They have the same atomic number but different umber of elelctrons 12)Helium is often used in observation balloons because it is? A. light and combustible B. light and non-combustible C. heavy and combustible D. heavy and non-combustible 13)Deliquescent substances are also? A. efflorescent B. anhydrous C. hygroscopic D. insoluble 14)When plastics and packaging materials made from chloroethene are burnt in the open, the mixture of gases released into the atmosphere is most likely to contain? A. ethane B. chlorine C. hydrogen chloride D. ethene 15)The difference between colloides and and suspensions is brought out clearly by the fact that while colloids? A. do not scatter light, suspensions do B. can be separated by filtration, suspension cannot be so separated C. can be separated by a membrane, suspensions cannot D. do not settle out on standing, suspensions do . 16)In general, an increase in temperature increases the solubility of a solute in water because? A. more solute molecules collide with each other B. most solutes dissolve with the evoltion of heat C. more solute molecules dissociate at hihger temperatures D. most solutes dissolve with absorption of heat 17) Neutralization involves a reaction between H3O+ and? A. CI- B. OH- C. NO3- D. CO32- 18) In the process of silver-plating a metal M, the metal M is the? A. anode and a direct current is used B. cathode and an alternating current is used C. anode and an alternating current is used D. cathode and a direct current is used 19) How many moles of copper would be deposited by passing 3F of electricity through a solution of copper (II) tetraoxosulpohate (IV)? (F = 96 500 C mol-) A. 0.5 B. 1.0 C. 1.5 D. 3.0 20) 2CL-(aq) → CI2(g) + 2e-(aq). The above half-cell reaction occuring at the anode during the electrolysis of dilute ZnCI2 solution is? A. ionization B. oxidation C. reduction D. recombination 21) Which of the following is a redox reaction? A. KCI(aq) + H2SO4(aq) → KHSO4(aq) + HCI(aq) B. 2FeBr2(aq) + Br4(aq) → 2FeBr3(aq) C. 3AgNO(aq) + FeCl3(aq) → 3AgCl(aq) + Fe(NO3)3(aq) D. H2CO3(aq) → H2O(I)2- + CO2(g) 22) Cr2O72-(aq) + 14H+(aq) + 6l-(aq) → 2Cr3+(aq) + 3l(g) + 7H2O(I). The change in the oxidation number of oxygen in the equation above is? A. 0 B. 1 C. 2 D. 7 23) If an equilibrium reaction has ∆H < O, the reaction will proceed favorably in the forward reaction at? A. low temperatures B. high temperatures C. all temperatures D. all pressures 24) Which of the following processes leads to increase in entropy? A. Mixing a sample of NaCl and sand B. Condensation of water vapour C. Boiling a sample of water D. Cooling a saturated solution 25) Which of the following equilibria is shifted to the right as a result of an increase in pressure? A. H2(g) + I2(g) 2HI(g) B. 2NO2(g) N2O4(g) C. PCl5(s) PCl3(s) + Cl2(g) D. 2O3(g) 3O2(g) 26) In the industrial production of hydrogen from natural gas, carbon (IV) oxide produced along with the hydrogen is removed by? A. washing with water under pressure B. passing the mixture into lime water C. using ammoniacal copper (l) chloride D. drying over phoshorus (V) oxide 27) Sulphur exists in six forms in the solid state. This property is known as? A. isomerism B. allotropy C. isotopy D. isomorphism 28) A gas that will turn orange potassium heptaoxodichromate (lV) solution to clear green is? A. sulphur (lV) oxide B. hydrogen sulphide C. sulphide (lV) oxide D. hydrogen chloride 29) Which of the following ions will give a white precipitate with aqueous NaOH and soluble in excess of the base? A. Ca2+ B. Mg2+ C. Zn2+ D. Cu2+ 30) In the extraction of iron in the blast furnace, limestone is used to? A. release CO2 for the reaction B. reduce the iron ore C. increase the strenght of the iron D. remove impurities 31) Which of the following compounds will impart a brick-red colour to a non-luminious bunsen flame? A. NaCl B. LiCl C. CaCl2 D. MgCl2 32) Group 1 A metals are not found free in nature because they? A. are of low melting and boiling points B. have weak metallic bonding C. conduct electricity and heat D. are very reactive 33) CHCl3 + Cl2 → HCl + CCl4. The reaction above is an example of? A. an addition reaction B. a substitution reaction C. a chlorination reaction D. a condensation reaction 34) Which of the following pairs has compounds that are isomers? A. Propanal and propanone B. Ethanoic acid and ethylmethanoate C. Ethanoic acid and ethane-1, 2-diol D. 2-methylbutane and 2, 2-dimethylbutane 35) Aromatic and aliphatic hydrocarbons can be distinguished from each other by the? A. action of bromine B. use of polymerization reaction C. action of heat D. use of oxidation reaction 36) The role of sodium chloride in the preparation of soap is to? A. purify the soap B. separate the soap from glycerol C. accelerate the decomposition of the fat or oil D. react with glycerol 37) CxHY + 4O2 → 3CO2 + 2H2O. The hydrocarbon, CxHY, in the reaction above is? A. propane B. propene C. propyne D. propanone 38) An example of a secondary amine is? A. propylene B. di-butylamine C. methylamine D. trimethylamine 39) The relatively high boiling points of alkanols are due to? A. ionic bonding B. aromatic character C. covalent bonding D. hydrogen bonding