JAMB UTME - Chemistry - 1985

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Question 6 Report

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?

an alkene

an alkane

an alkyne

tetrachloromethane

dichloromethane

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Question 7 Report

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?

18.6k

100.0k

298.0k

1192.0k

4768.0k

Answer Details

\frac{P_{1} V_{1}}{T_{1}} = \frac{4 P_{1} \times 4 V_{1}}{T_{2}}

i.e $\frac{P_{1} V_{1}}{298} = \frac{4 P_{1} \times 4 V_{1}}{T_{2}}$

T2 = $\frac{298 \times 4 P_{1} \times 4 V_{1}}{P_{1} V_{1}}$

= 298 + 16 = 4768.0k

Read lesson note on Kinetic Theory Of Matter And Gas Laws (JAMB)

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Question 8 Report

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

increase in temperature, decrease in pressure

increase in temperature, increase in pressure

decrease in temperature,increase in pressure

decrease in temperature, decrease in pressure

constant in temperature, increase in pressure

Energy Changes

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Question 9 Report

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)

60

72

82

89

92

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Question 10 Report

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

reacts with glycerol

purifies the soap

accelerates the decomposition of the fat or oil

separates the soap from the glycerol

converts the fatty acid to its sodium salt

Acids, Bases And Salts

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Question 11 Report

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)

0.457g

0.500g

0.882g

0.914g

1.00g

Answer Details

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

Read lesson note on Electrolysis (JAMB)

Electrolysis

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Question 12 Report

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

Carbon

Air

Water

Oxygen

Hydrogen

Answer Details

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

Read lesson note on Separation Of Mixtures And Purification Of Chemical Substances (JAMB)

Separation Of Mixtures And Purification Of Chemical Substances

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Question 13 Report

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

Copper

Mercury

Silver

Zinc

Gold

Metals And Their Compounds

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Question 14 Report

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)

Y is twice as soluble as X

X is twice as soluble as Y

X and Y are soluble to the same extent

X is three times as soluble as Y

Y is three times as soluble as X

Solubility

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Question 15 Report

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

A

B

C

D

E

Solubility Of Substances (Ghana Only)

Acids, Bases And Salts

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Question 16 Report

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?

pink

purple

orange

blue-black

green

Acids, Bases And Salts

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Question 17 Report

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

16

18

20

22

24

Structure Of The Atom

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Question 18 Report

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

hydrogenation

condensation

pyrolysis

dehydration

cracking

Organic Compounds

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Question 19 Report

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

C8H22O3

C6H10O3

C12H12O

C6H12O

C3H6O

Answer Details

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

Read lesson note on Chemistry Of Carbon Compounds (Nigeria Only) (WAEC)

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Question 20 Report

Which of the following conduct electricity?

sulfur

graphite

diamond

red phosphorus

yellow phosphorus

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Question 21 Report

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

a carbonxylic acid

an alkane

an alkene

an alkyne

an akanone

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Question 22 Report

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?

NaOH

KOH

Mg(OH)2

Zn(OH)2

Ca(OH)2

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Question 23 Report

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

zinx is not rendered passive by acid

hydrogen produced is oxidized to water

oxides of nitrogen are produced

all nitrates are soluble in water

trioxonitrate(v)acid is a strong acid

Acids, Bases And Salts

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Question 24 Report

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?

Na2SO4

Na2S

Na2S2O3.5H2O

Na2CO3

NaHCO3

Acids, Bases And Salts

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Question 25 Report

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

Mn2+

Cl-

H2O

MnO-4

Cl2

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Question 26 Report

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?

CO2 and NH3

CO and NH3

SO2 and H2O

CO2 and H2O

SO2 and NH3

Oxidation And Reduction

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Question 27 Report

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

S, T and U

V, W and X

S and T only

P, Q and R

V, W, X and S

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Question 28 Report

Tetraoxosulphate (IV) ions are finally tested using?

acidified silver nitrate

acidified barium chloride

ime-water

dilute hydrochloric acid

acidified lead nitrate

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Question 29 Report

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

purer than sample 2

slightly denser than sample 2

in all respects the same as sample 2

colourless but sample 2 has a light brown colour

slightly less reactive than sample 2

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Question 30 Report

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?

i, iv and v

iv and v

i and iv

ii and v

ii, iii and iv

Acids, Bases And Salts

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Question 31 Report

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

0.2 moles

0.7 moles

1.5 moles

2.0 moles

3.0 moles

Solubility Of Substances (Ghana Only)

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Question 32 Report

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?

25.0 moles

12.5 moless

6.25 moles

3.125 moles

0.625 moles

Answer Details

Fe2O3 = 56 x 2 + 48 = 160 = 1 moles

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

Read lesson note on Stoichiometry And Chemical Reactions (WAEC)

Stoichiometry And Chemical Reactions

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Question 33 Report

The oxidation of

2-butanone

2-butanal

butane

butanoic acid

3-butanal

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Question 34 Report

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)

0.5

2.0

3.0

4.0

5.0

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Question 35 Report

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

only 10g of X undissolved

only 16 g of Y undissolved

10 g of X and 16 g of Y undissolved

all X and Y dissolved

all X and Y undissolved

Solubility

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Question 36 Report

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

NaOH.H2O

NaOH.N2

Na2CO3O

NaHCO3

NaNO3O

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Question 37 Report

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

increase the amount of Z produced in a given time

increases the rate of change in concentrations of X, Y and Z

increases the rate of disapearance of X and Y

increases the rate of the forward reaction

decreases the amounts of X and Y left after the attainment of equilibrium

Chemical Kinetics And Equilibrium System (Nigeria Only)

Chemical Kinetics And Equilibrium Systems (Ghana Only)

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Question 38 Report

In the reaction $ \mathrm{H_2(g)O \rightarrow H_2(g) + \frac{1}{2}O_2(g)} $

$ \Delta H = -2436000\ \mathrm{KJ} $, which of the following has no effect on the equilibrium position?

Adding argon to the system

Lowering the temperature

Adding hydrogen to the system

Decreasing the pressure

Increasing the temperature

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Question 39 Report

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

NaGaO3

Na2Ga(OH)3

NaGa(OH)3

NaGa(OH)4

NaGaO

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Question 40 Report

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

Calcium oxide (CaO)

Sodium oxide (Na2O)

Copper (ll) oxide (CuO)

D) Tri-iron tetroxide (Fe3O4)

Aluminium oxide (Al2O3)

Chemical Combination

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Question 41 Report

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

A

B

C

D

E

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Question 42 Report

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

2-methyl-3-pentene

4-methyl-2-pentane

2-methyl-2-pentene

4-methylpent-2-ene

2-methyl-3-pentane

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Question 43 Report

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

Al and Mg

Zn and Fe

Zn and Pb

Pb and H

Au and Hg

Oxidation And Reduction

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Question 44 Report

Hydrogen diffuses through a porous plug

at the same rate as oxygen

at a slower rate than oxygen

twice as fast as oxygen

three times as fast as oxygen

four times as fast as oxygen

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Question 45 Report

The function of sulphur during vulcanization rubber is to?

act as catalyst for the polymerization of rubber molecules

convert rubber from thermosetting to thermo plastics polymer

from chains which bind rubber molecules together

break down rubber polyer

shorten the chain length of rubber polyer

Acids, Bases And Salts

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Question 46 Report

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?

convection currents

small changes

small changes in temperature

a chemical reaction between the pollen grain and water

the bombardment of the pollen grains by molecules of water

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Question 47 Report

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?

water

toluene

ethanol

butan-2-ol

none