JAMB UTME - Chemistry - 1985

An organic compound contains 72% carbon, 12% hydrogen and 16% oxygen by mass. The empirical formula of the compound is

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carbon = 72%, hydrogen = 12%, 16%

Dividing by the atomic weight we have for C = $\frac{5}{1}$ = 6

H = $\frac{12}{1}$ = 12

O = $\frac{16}{16}$ = 1

Divide by the smallest number, we have = $\frac{6}{1}$ = 6

H = $\frac{12}{1}$ = 12

O = $\frac{1}{1}$ = 1

The formula is C6H12O

When marble is heated to about 1473 K, another white solid is obtained which reacts vigorously with water to give an alkaline solution. The solution contains?

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When pollen grains are suspended in water and viewed through a microscope, they appear to be in a state of constant but erratic motion. This is due to?

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3.0g of a mixture of potassium carbonate and potassium chloride were dissolved in a 25cm3 of this solution required required 40.00cm3 of 0.1M HCl for neutralization. What is the percentage by weight of K2CO3 in the mixture. (K = 39, O = 16, C = 12)

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Complete hydrogenation of ethyne yields?

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In the experiment, which of the following observations would suggest that a solid sample is a mixture? The

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Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink.Which of the above are NOT typical properties of alkalis?

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If the ONLY pollutants found in the atmosphere over a city are oxides of nitrogen, suspended lead compounds. carbon monoxide and high levels of methane, the probable source(s) of the pollution must be?

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Which of the following roles does sodium chloride play in soap preparation? It

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A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).

Y and Z are respectively?

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The oxidation of

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The process involved in the conversion of an oil into margarine is known as?

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2MnO-4 + 10Cl- + 16H+ → 2Mn2+ + 5Cl2 + 8H2O. Which of the substances serves as an oxidizing agent?

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A certain volume of gas at 298k is heated such that its volume and pressure are now four times the original values. What is the new temperature?

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$\frac{P_1{V}_1}{T_1}=\frac{4P_1\times 4V_1}{T_2}$

i.e $\frac{P_1{V}_1}{298}=\frac{4P_1\times 4V_1}{T_2}$

T2 = $\frac{298\times 4P_1\times 4V_1}{P_1{V}_1}$

= 298 + 16 = 4768.0k

The diagram shown above represents the solubility curves of two salts, X and Y, in water, use this diagram to answer the question. If 80 g each of X and Y are taken up in 100 g of water at 353 K we shall have

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The atomic number of an element whose cation, X2+, has the ground state electronic configuration 1s22s22p63s22p6 is?

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Hydrogen diffuses through a porous plug

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Use the following option above to answer this question. Which of the following is the functional group of carboxylic acids?

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0.499g 0f CuSO4.xH2O when heated to constant weight gave a residue of 0.346g. the value of x is? (Cu = 63.5, S = 32.0, O = 16, H = 1)

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Which of the following conduct electricity?

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X + Y = Z is an equilibrium reaction. The addition of a catalyst?

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Which of the following metals will displace iron from a solution of iron(ll)tetraoxosulphate(lV)?

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Which of the following substances is the most abundant in the universe?

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Element Abundance
Hydrogen 40,000
Helium 3,100
Oxygen 22
Neon 8.6
Nitrogen 6.6
Carbon 3.5
Silicon 1
Magnesium 0.91
Iron 0.6
Sulfur 0.38

A man suspected of being drunk is made to pass his breath into acidified potassium dichlormate solution. If his breath carries a significant level of ethanol, the final colour of the solution is?

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The boiling point of water, ethanol, toluene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively. Which liquid has the highest vapour pressure at 323.0k?

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Copper sulphate solution is electolysed using platinum electrodes A. current of 0.193 amperes is passed for 2hrs. How many grams of copper are deposited? (cu = 63.5, F = 96500 coulombs)

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Time = 2hrs 120mm = 120 x 60secs

current = 0.193amps

Quantity of electricity = 120 x 0.193

= 60 x 23.16

96,500 deposits 63.5 gms of Cu

60 x 23.2 will deposit $\frac{63.5\times 60\times 23.2}{96500}$

= 0.457

Given that the molecular mass of iron is 56 and that of oxygen is 16, how many moles of iron(iii)oxide will be contained in 1kg of the compound?

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Fe2O3 = 56 x 2 + 48 = 160 = 1 moles

1000gm will contain $\frac{1000}{160}$ = 6.25 moles

The energy change (ΔH) for the reaction CO(g) + (1)/(2)O2(g) → is?(ΔHi(CO) = -110.4 kJ mol-) (ΔHi(CO2) = -393 kJ mol-)

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The energy charge for the reaction is - (393 - HO.4) = -282.9 kJ

Solid sodium hydroxide on exposure to air absorbs a gas and ultimately gives another alkaline substance with the molecular formula?

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The diagram shown above represents the solubility curves of two salts, X and Y, in water, use this diagram to answer the question. If the molar mass of X is 36 g, the number of moles of X dissolved at 343 K is

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The function of sulphur during vulcanization rubber is to?

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A correct electrochemical series can be obtained from K, Na, Ca, Al, Mg, Zn, Fe, Pb, H, Cu, Hg, Ag, Au by interchanging?

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Addition of dilute hydrochloride acid to an aqueous solution of a crystalline salt yield a yellow precipitate and a gas which turned dichromate paper green. The crystalline salt was probably?

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Which of the following is used in the manufacture of bleaching powder?

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The I.U.P.A.C name for the compound

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What is the formula of sodium gallate if gallium (Ga)shows an oxidation number of + 3?

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In what respect will two dry samples of nitrogen gas differ from each other if sample 1 is prepared by completely removing CO2 and O2 from air, and sample 2 is prepared by passing purified nitrogen(i)oxide over heated copper? sample 1 is

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The diagram shown above represents the solubility curves of two salts, X and Y, in water, use this diagram to answer the question. At room temperature (300 K)

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Use the above options to the question. The products formed on hydrolysis of

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An organic compound decolourized acidified KMnO4 solution but failed to react with ammoniacal silver nitrate solution. The organic compound is likely to be?

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Which of the following compounds is NOT the correct product formed when the parent metals is heated in air?

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Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because

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Figure 1 above shows part of the periodic Table which of the elements belongs to the p-block?

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In the reaction H2(g)O $\to$ H2(g) + 1/2O2(g)

ΔH = -2436000 KJ, which of the following has no effect on the equilibrium position?

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A colourless organic compound X was burnt in excess air to give two colourless and odourless gases, Y and Z, as products. X does not decolorize blue bromine vapour, Y turns lime milky while Z gives a blue colour with copper (ll) tetraoxosulphate (IV).

Compound X is?

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An aqueous solution of an inorganic salt gave white precipitate (i) soluble in excess aqueous NaOH (ii) insoluble in excess aqueous NH3 (iii) with dilute HCl. The cation present in the inorganic salt is?

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Tetraoxosulphate (IV) ions are finally tested using?

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A certain industrial process is represented by the chemical equation 2A(g) + B(g) $\to$ C(g) + 3D(g) $\Delta$H = X kJmol-1. Which of the following conditions will favour the yield of the products?

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