JAMB UTME - Chemistry - 2008
Vraag 1 Verslag
NH3(g) + HCl(s) → NH4Cl(s)
The entropy change in the system above is
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Vraag 2 Verslag
16.8 g of sodium hydrogen trioxocarbonate (IV) is completely decomposed by heat. Calculate the volume of carbon(IV) oxide given off s.t.p
[Na 23, C = 12, O = 16, H = 1, Molar volume of a gas at s.t.p = 22.4 dm3]
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2NaHCO3(s) → Na2CO3(s) + H2O(l) + CO2
Relative molecular mass of NaHCO3 = 23 +1 + 12 + 16 * 3 = 84smol-1
2 * 84g of NaHCO3 will be liberated 22.4dm3 or CO2 at s.t.p
16.8g of NaHCO3 will libertae (16.8 * 22.4)/(2 * 84) = 2.24 dm3
Vraag 3 Verslag
2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
From the equation above, calculate the mass of sodium hydroxide produced by 2.3g of sodium.
[H = 1, O = 16, Na = 23]
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2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g)
Relative molecular mass of NaOH = 23 + 16 + 1 = 40smol-1
2 * 23g of sodium react with water to produce
2 * 40g of NaOH
∴ 2.3g of sodium will react with water to produce
(2.3 * 40 * 2)/(23 * 2) = 4.00g
Vraag 5 Verslag
The oxidation state of carbon in HCOOH is
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HCOOH
O.N of H + O.N of C + 2* O.N of oxygen of
H = 0
1 + X + 2X - 2 + 1 = 0
2 + X -4 = 0
X = 4 - 2 = +2
Vraag 6 Verslag
117.0g of sodium chloride was dissolved in the solubility in 1.0dm3 of distilled water at 25oC. Determine the solubility in mol dm-3 of sodium chloride at that temperature
[Na = 23, Cl = 35.5]
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Relative molecular mass of NaCl = 23 + 35.5 = 55.5 g/mol
No. of mole of NaCl = 117/55.5 = 2.1 mol
Vraag 7 Verslag
A hydrocarbon X with a molar mass of 26 consists of 92.3% carbon. What is its molecular formular
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% of H2 = 100 - 92.3 = 7.7%
mole = 92.3/12 7.7/1
7.1/7.1 7.1/7.1
empirical formula = CH
(CH)n = 26
(12 + 1)n = 26
(13)n = 26
n = 26/13 = 2
molecular formula = C2H2
Vraag 9 Verslag
0.05 mol dm-3 HCl is neutralized by 25 cm3 NaOH. If the volume of acid used is 32.00cm3, what is the concentration of the base
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HCl + NaOH → NaCl + H2O
CAVA = NA/NB = (0.05 * 32)/(CB * 25)
∴ CB = (0.05 * 32)/25 = 0.064 mol dm-3
Vraag 10 Verslag
In the periodic table, the electrical and thermal conductivities are properties of elements that
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Vraag 11 Verslag
When a solution of ammonium trioxocarbonate (IV) is added to a solution of an unknown salt, a white precipitate which is soluble in dilute hydrochloric acid but insoluble in ethanoic acid is formed. This indicates the presence of
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Vraag 12 Verslag
300 cm3 of gas has a pressure of 800 mmHg. If the pressure is reduced to 650 mmHg, find its volume
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P1V1= P2V2
800 * 300 = 650 * V2
V2 = (800 * 300)/650 = 369.23 cm3
Vraag 14 Verslag
Reduction of nitroalkanes, nitrites and amides is a route for the preparation of
Vraag 15 Verslag
Which of the following compounds of trioxonitrate (V) will decomposes to give dinitrogen (i) oxide and water when heated?
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Vraag 18 Verslag
The product obtained when a mixture of benzene vapour and hydrogen are passed over nickel catalyst at 180oC is
Vraag 21 Verslag
If a given quantity of electricity liberates 0.65g of Zn2+, what amount of Hg2+ would be liberated by the same quantity of current?
[Zn = 65, Hg = 201]
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Vraag 24 Verslag
Chlorophyll obtained from given leaves of plant can be shown to be composed of more than one coloured component by the technique of
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Vraag 25 Verslag
When a few drops of water is added to a blue anhydrous cobalt (II) chloride, the colour changes to
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Vraag 28 Verslag
The atom of an element X is represented as yzX . The basic chemical properties of X depend on the value of
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Vraag 29 Verslag
The IUPAC nomenclature for the structure above is
Vraag 30 Verslag
Insoluble salts can be prepared by
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Two soluble metal salts react with each other to form one soluble salt and one insoluble salt . Lead nitrate solution and sodium chloride solution react to produce solid lead chloride , leaving soluble sodium nitrate in solution. The lead chloride can be recovered by filtration.
Vraag 31 Verslag
Use the diagram to answer this question.
The colour of the fountain water is
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Vraag 32 Verslag
If the silver mirror test is positive, it indicates the presence of an
Vraag 33 Verslag
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The correct answer is 11.
pH = -log(H+) Or 14 - pOH
pOH = -log(0.001)
pOH = 3
pH = 14 - 3 = 11
Vraag 34 Verslag
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Vraag 35 Verslag
If glucose is heated with concentration tetraoxosulphate (VI) acid, it will be dehydrated to
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Vraag 36 Verslag
Use the diagram to answer this question.
The gas that can be used to demonstrate the experiment is
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Vraag 37 Verslag
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Vraag 38 Verslag
In countries where the temperature falls below 273K, salt is always sprinkled on the icy road in order to
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Vraag 39 Verslag
The substance that is used in the steel industry for the removal of carbon, sulphur and phosphorus impurities from pig iron is
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Vraag 40 Verslag
The uncovered raw food that is sold along major roads is likely to contain some amounts of
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Vraag 41 Verslag
The experiment that showed that atoms have tiny positively charged nucleus was first carried out by
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Vraag 42 Verslag
In recharging a lead-acid accumulator, the reaction at the cathode can be represented as
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Vraag 43 Verslag
Detergents are manufactured with straight hydrocarbon chains so as to make them
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Vraag 44 Verslag
Reduction of alkanonoes with LialH4 produces
Vraag 46 Verslag
The rate of a reaction usually decrease in the concentration of reactants because
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Vraag 47 Verslag
In the course of purifying water for town supply the water is passed through large settlings tanks, containing sodium aluminate (III) to remove
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Vraag 49 Verslag
Diffusion is slowest in solid particles than in particles of liquid and gases because
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