2014 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS Leave a Comment / Jamb Chemistry / By Jamb Tutor Report a question What’s wrong with this question? You cannot submit an empty report. Please add some details. 0% Created by Jamb TutorJamb Chemistry 2014 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS 1 / 48 Category: JAMB Chemistry 2014 1. Which Question Paper Type of Chemistry is given to you? a) Type F b) Type E c) Type L d) Type S The paper type identifies the specific version of the exam given to the candidate. 2 / 48 Category: JAMB Chemistry 2014 2. A mixture is different from a compound because a) Properties of a compound are those of its individual constituents, while those of a mixture differ from its constituents b) A mixture is always homogeneous, while a compound is not c) The constituents of a compound are chemically bound together, while those of a mixture are not d) A mixture can be represented by a chemical formula, while a compound cannot In a mixture, the constituents are not chemically combined and retain their individual properties. 3 / 48 Category: JAMB Chemistry 2014 3. What is the percentage of sulphur in sulphur (IV) oxide? a) 66% b) 25% c) 40% d) 50% Calculate the molar mass of $SO_2$: S (32) + $O_2$ $(16 × 2) = 64$ g/mol. Percentage of S is $\frac{32}{64} × 100% = 50%$. 4 / 48 Category: JAMB Chemistry 2014 4. A gas X diffuses twice as fast as gas Y. If the relative molecular mass of X is 32, calculate the relative molecular mass of Y. a) 128 b) 8 c) 16 d) 64 According to Graham’s law: $Rate_X/Rate_Y = \sqrt{M_Y/M_X} \Rightarrow 2 = \sqrt{M_Y/32} \Rightarrow M_Y = 128$. 5 / 48 Category: JAMB Chemistry 2014 5. 200 $cm^3$ of a gas at $25^{\circ}$C exerts a pressure of 700 mmHg. Calculate its pressure if its volume increases to 350 $cm^3$ at $75^{\circ}$C. a) 342.53 mmHg b) 1430.54 mmHg c) 467.11 mmHg d) 400.00 mmHg Use combined gas law: $\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}$. Convert temperatures to Kelvin. Solve for $P_2$. 6 / 48 Category: JAMB Chemistry 2014 6. An element X has electron configuration $1s^2 2s^2 2p^6 3s^2 3p^5$. Which of the following statements is correct about the element? a) It has a completely filled p-orbital b) It has 5 electrons in its outermost shell c) It belongs to Group II on the periodic table d) It is a halogen The element has 7 valence electrons and is a halogen (Group VII). 7 / 48 Category: JAMB Chemistry 2014 7. Beryllium and aluminum have similar properties because they a) Are both metals b) Belong to the same group c) Belong to the same period d) Are positioned diagonally to each other They are diagonally related in the periodic table, exhibiting similar properties. 8 / 48 Category: JAMB Chemistry 2014 8. If the difference in electronegativity of elements P and Q is 3.0. The bond that will be formed between them is a) Metallic b) Covalent c) Coordinate d) Ionic A large electronegativity difference (>1.7) leads to an ionic bond. 9 / 48 Category: JAMB Chemistry 2014 9. How many protons, neutrons, and electrons respectively are present in the element $^{60}_{27}$Co? a) 27, 33, 33 b) 33, 27, 27 c) 27, 33, 27 d) 60, 33, 60 Atomic number = protons = 27; Neutrons = mass number – atomic number = 60 – 27 = 33; Electrons = 27 (neutral atom). 10 / 48 Category: JAMB Chemistry 2014 10. The radioactive radiation used in studying the arrangement of particles in giant organic molecules is a) γ-rays b) α-particles c) X-rays d) β-particles X-rays are used in X-ray crystallography to study large molecules. 11 / 48 Category: JAMB Chemistry 2014 11. A silicon-containing ore has 92% $^{28}$Si, 5% $^{29}$Si, and 3% $^{30}$Si. Calculate the relative atomic mass of the silicon. a) 14 b) 29 c) 28.11 d) 28 Relative atomic mass = $(92 × 28 + 5 × 29 + 3 × 30)/100 = 28.11$. 12 / 48 Category: JAMB Chemistry 2014 12. The nitrogen obtained from air has a density higher than the one from nitrogen-containing compounds because the one from air is contaminated with a) Water vapor b) Oxygen c) Rare gases d) Carbon (IV) oxide Air-derived nitrogen contains rare gases (argon, etc.), increasing density. 13 / 48 Category: JAMB Chemistry 2014 13. Water is said to be temporarily hard when it contains a) Ca(HCO$_3$)$_2$ and Mg(HCO$_3$)$_2$ salts b) Ca(HCO$_3$)$_2$ and CaCO$_3$ salts c) Mg(HCO$_3$)$_2$ and CaSO$_4$ salts d) CaSO$_4$ and Ca(HCO$_3$)$_2$ salts Temporary hardness is due to the presence of calcium and magnesium bicarbonates. 14 / 48 Category: JAMB Chemistry 2014 14. On exposure to the atmosphere, a hydrated salt loses its water of crystallization to become anhydrous. This phenomenon is referred to as a) Efflorescence b) Deliquescence c) Hygroscopy d) Hydrolysis Efflorescence is the loss of water of crystallization from a hydrated salt. 15 / 48 Category: JAMB Chemistry 2014 15. 16.55 g of lead (II) trioxonitrate (V) was dissolved in 100 g of distilled water at $20^{\circ}$C. Calculate the solubility of the solute in mol dm$^{-3}$. [Pb=207, N=14, O=16] a) 0.05 mol/dm$^3$ b) 2.00 mol/dm$^3$ c) 1.00 mol/dm$^3$ d) 0.50 mol/dm$^3$ Molar mass of Pb(NO$_3$)$_2$ = 331 g/mol. Moles = $\frac{16.55}{331}$ = 0.05 mol. Solubility = 0.05 mol/dm$^3$. 16 / 48 Category: JAMB Chemistry 2014 16. The dispersion of a liquid in a liquid medium will give a) An emulsion b) A fog c) A gel d) An aerosol A liquid-liquid colloidal system is called an emulsion. 17 / 48 Category: JAMB Chemistry 2014 17. The major and most effective way of controlling pollution is to a) Improve machinery so that substances released from combustion are less harmful b) Pass strict laws against it by individuals and companies c) Educate people on the causes and effects of pollution d) Convert chemical wastes to harmless substances before releasing them into the environment Converting chemical wastes to harmless substances minimizes environmental impact. 18 / 48 Category: JAMB Chemistry 2014 18. The basicity of CH$_3$COOH is a) 4 b) 1 c) 2 d) 3 Basicity is the number of replaceable hydrogen ions; acetic acid is monobasic (basicity = 1). 19 / 48 Category: JAMB Chemistry 2014 19. The colour of litmus in a neutral medium is a) Purple b) Pink c) Yellow d) Orange In neutral solutions, litmus paper is purple. 20 / 48 Category: JAMB Chemistry 2014 20. The mathematical expression of pH is a) $\log_{10}[OH^-]$ b) $\log_{10}(\frac{1}{[H_3O^+]})$ c) $\log_{10}[H_3O^+]$ d) $\log_{10}(\frac{1}{[OH^-]})$ pH = $-\log_{10}[H^+]$; alternatively, pH = $\log_{10}(\frac{1}{[H_3O^+]})$. 21 / 48 Category: JAMB Chemistry 2014 21. Which of the following salts will turn blue litmus red? a) Sodium tetrahydroxozincate(II) b) Potassium hydrogen tetraoxosulphate(IV) c) Sodium trioxocarbonate(IV) d) Zinc chloride hydroxide Potassium hydrogen tetraoxosulphate(IV) is acidic, so it turns blue litmus red. 22 / 48 Category: JAMB Chemistry 2014 22. Zn(s) + CuSO$_4$(aq) → ZnSO$_4$(aq) + Cu(s). In the reaction above, the oxidation number of the reducing agent changes from a) 0 to +4 b) 0 to +2 c) +1 to +2 d) +1 to +3 Zn goes from 0 to +2; it loses electrons and is oxidized, acting as reducing agent. 23 / 48 Category: JAMB Chemistry 2014 23. H$_2$O(g) + C(s) → H$_2$(g) + CO(g). The oxidizing agent in the reaction above is a) CO(g) b) C(s) c) H$_2$O(g) d) H$_2$(g) H$_2$O provides oxygen, accepting electrons; thus, it’s the oxidizing agent. 24 / 48 Category: JAMB Chemistry 2014 24. Calculate the quantity of electricity in coulombs required to liberate 10 g of copper from a copper compound. [Cu=64, F=96,500 C mol$^{-1}$] a) 32,395.50 b) 30,156.30 c) 60,784.50 d) 15,196.50 Moles of Cu = $\frac{10}{64}$ = 0.15625 mol. Cu$^{2+}$ + 2e$^-$ → Cu; Q = n × F × 2 = 0.15625 × 96,500 × 2 = 30,156.25 C. 25 / 48 Category: JAMB Chemistry 2014 25. How many faradays of electricity are required to produce 0.25 mol of copper? a) 1.00 F b) 0.01 F c) 0.05 F d) 0.50 F Cu$^{2+}$ + 2e$^-$ → Cu; Faradays = moles × number of electrons = 0.25 × 2 = 0.5 F. 26 / 48 Category: JAMB Chemistry 2014 26. In the diagram below, Z represents… a) Heat of reaction b) Activation energy c) Free energy d) Entropy of reaction Z indicates the activation energy of the reaction. 27 / 48 Category: JAMB Chemistry 2014 27. If the change in free energy of a system is -899 J mol$^{-1}$ and the entropy change is 10 J mol$^{-1}$K$^{-1}$ at $25^{\circ}$C, calculate the enthalpy change. a) +2081 J mol$^{-1}$ b) -2081 J mol$^{-1}$ c) -649 J mol$^{-1}$ d) +649 J mol$^{-1}$ ΔG = ΔH – TΔS; ΔH = ΔG + TΔS = -899 + (298 × 10) = -899 + 2980 = +2081 J mol$^{-1}$. 28 / 48 Category: JAMB Chemistry 2014 28. In an equilibrium reaction, which of the following conditions indicates that maximum yield of the product will be obtained? a) Equilibrium constant is very large b) ΔH – TΔS = 0 c) ΔH > TΔS d) Equilibrium constant is less than zero A very large equilibrium constant means products are favored at equilibrium. 29 / 48 Category: JAMB Chemistry 2014 29. In a chemical reaction, the change in concentration of a reactant with time is a) Entropy of reaction b) Enthalpy of reaction c) Rate of reaction d) Order of reaction The rate of reaction is defined as the change in concentration over time. 30 / 48 Category: JAMB Chemistry 2014 30. 2CrO$_4^{2-}$(aq) + 2H$^+$(aq) ⇌ Cr$_2$O$_7^{2-}$(aq) + H$_2$O(l). What happens to the reaction above when the hydrogen ion concentration is increased? a) More of the products will be formed b) The reaction will not proceed c) The equilibrium position will shift to the right d) The equilibrium position will shift to the left According to Le Chatelier’s principle, increasing [H$^+$] shifts equilibrium to the right, forming more Cr$_2$O$_7^{2-}$. 31 / 48 Category: JAMB Chemistry 2014 31. Which of the following will liberate hydrogen from dilute tetraoxosulphate(VI) acid? a) Lead b) Magnesium c) Copper d) Gold Magnesium is above hydrogen in the reactivity series and will displace hydrogen from acids. 32 / 48 Category: JAMB Chemistry 2014 32. In the laboratory preparation of ammonia, the flask is placed in a slanting position so as to a) Prevent condensed water from breaking the reaction flask b) Enable the proper mixing of the reactants in the flask c) Enhance the speed of the reaction d) Prevent formation of precipitate This prevents condensed water from flowing back and cracking the hot flask. 33 / 48 Category: JAMB Chemistry 2014 33. Which of these gases is employed as an anesthetic? a) N$_2$O b) NO$_2$ c) NH$_3$ d) NO Nitrous oxide (N$_2$O) is used as an anesthetic. 34 / 48 Category: JAMB Chemistry 2014 34. Sulphur(IV) oxide is a strong reducing agent in the presence of water due to the formation of a) Hydroxide ion b) Sulphur(VI) oxide c) Hydrogen sulphide d) Trioxosulphate(IV) salt It forms trioxosulphate(IV) ions (HSO$_3^-$), which can act as reducing agents. 35 / 48 Category: JAMB Chemistry 2014 35. A metal that forms soluble trioxosulphate(IV) ion is a) Barium b) Potassium c) Manganese d) Aluminum Potassium forms soluble sulphites (trioxosulphate(IV) salts). 36 / 48 Category: JAMB Chemistry 2014 36. Copper is displaced from the solution of its salts by most metals because it a) Is a transition element b) Is at the bottom of the activity series c) Is very reactive d) Has completely filled 3d orbitals Copper is less reactive and is lower in the activity series than many metals. 37 / 48 Category: JAMB Chemistry 2014 37. The colored nature of transition metal ions is associated with their partially filled a) f-orbital b) s-orbital c) p-orbital d) d-orbital Partially filled d-orbitals allow for d-d electronic transitions, causing color. 38 / 48 Category: JAMB Chemistry 2014 38. Aluminum containers are frequently used to transport trioxonitrate(V) acid because aluminum a) Has a silvery-white appearance b) Has a low density c) Does not react with the acid d) Does not corrode Aluminum forms a protective oxide layer, preventing reaction with the acid. 39 / 48 Category: JAMB Chemistry 2014 39. 2-methylbutan-2-ol is an example of a a) Dihydric alkanol b) Tertiary alkanol c) Secondary alkanol d) Primary alkanol It is a tertiary alkanol because the hydroxyl group is attached to a tertiary carbon. 40 / 48 Category: JAMB Chemistry 2014 40. The reaction between ammonia and ethyl ethanoate produces a) Propanol and ethanamide b) Propanol and propanamide c) Ethanol and propanamide d) Ethanol and ethanamide Ammonolysis of an ester yields ethanol and ethanamide. 41 / 48 Category: JAMB Chemistry 2014 41. The decarboxylation of ethanoic acid will produce carbon(IV) oxide and a) Methane b) Ethane c) Propane d) Butane Decarboxylation removes CO$_2$, yielding methane from ethanoic acid. 42 / 48 Category: JAMB Chemistry 2014 42. The compound above is an a) Alkanal b) Alkanone c) Alkanoate d) Alkanol Based on the structure (CHO group), it is an alkanal (aldehyde). 43 / 48 Category: JAMB Chemistry 2014 43. The compound that will react with sodium hydroxide to form salt and water is a) C$6$H${12}$O$_6$ b) (CH$_3$)$_3$COH c) CH$_3$CH=CH$_2$ d) CH$_3$CH$_2$COOH Carboxylic acids react with bases to form salt and water; propanoic acid fits. 44 / 48 Category: JAMB Chemistry 2014 44. Which of the following compounds in solution will turn red litmus paper blue? a) C$_2$H$_5$OH b) CH$_3$COOH c) CH$_3$NH$_2$ d) C$6$H${12}$ An amine (organic base) will turn red litmus blue; option C is an amine. 45 / 48 Category: JAMB Chemistry 2014 45. The dehydration of ammonium salts of alkanoic acids produces a compound with the general formula a) RCOOR' b) RCONH$_2$ c) RCN d) ROH Dehydration of ammonium alkanoates yields amides: RCONH$_2$. 46 / 48 Category: JAMB Chemistry 2014 46. Which of the following fractions is used as raw material for the cracking process? a) Kerosene b) Lubricating oil c) Bitumen d) Diesel oils Lubricating oil fractions are often used in cracking to produce smaller alkanes and alkenes. 47 / 48 Category: JAMB Chemistry 2014 47. An organic compound with a pleasant smell is likely to have a general formula a) C$n$H${2n+1}$CHO b) C$n$H${2n+1}$COOH c) C$n$H${2n+1}$COOC$n$H${2n+1}$ d) C$n$H${2n+1}$COC$n$H${2n+1}$ Esters (RCOOR’) have fruity smells and the general formula C$n$H${2n+1}$COOC$n$H${2n+1}$. 48 / 48 Category: JAMB Chemistry 2014 48. A primary amide is generally represented by the formula a) RCOOR b) RCONH$_2$ c) RCONHR d) RCONR Primary amide has the formula RCONH$_2$. Your score is The average score is 0% LinkedIn Facebook Twitter VKontakte 0% Restart quiz Anonymous feedback Send feedback
