JAMB UTME - Chemistry - 2017

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Question 2 Report

The IUPAC nomenclature of the structure above is

3-methybut-3-ene

2-methylbut-1-ene

2-ethylprop-1-ene

2-methylbut-2-ene

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Question 3 Report

If 100cm3 of oxygen pass through a porous plug is 50 seconds, the time taken for the same volume of hydrogen to pass through the same porous plug is? [O = 16, H = 1]

10.0s

12.5s

17.7s

32.0s

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Question 4 Report

The oxidation number of iodine in KIO3 is

+7

+3

+5

+6

Oxidation And Reduction

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Question 5 Report

Incomplete oxidation of ethanol yields

CH3COOH

CH3COCH3

CH3CH2OCH2CH3

CH2CHO

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Question 6 Report

Calculate the mass of copper deposited when a current of 0.5 ampere was passed through a solution of copper(II) chloride for 45 minutes in an electrolytic cell. [Cu = 64, F = 96500Cmol-1]

0.300g

0.250g

0.2242g

0.448g

Answer Details

M =

\frac{Molar mass × Quantity of Electricity}{96500 × no of charge}

= $\frac{M m I T}{96500 n}$

Copper II Chloride = CuCl2

CuCl2 → Cu2+ + 2Cl2

Mass of compound deposited = $\frac{Molar mass × Quantity of Electricity}{96500 × no of charge}$

Q = IT

I = 0.5A

T = 45 × 60

T = 2700s

Q = 0.5 × 2700

= 1350c

Molarmass = 64gmol-1

no of charge = + 2

Mass = $\frac{64 \times 1350}{96500 \times 2}$

Mass = 0.448g

Read lesson note on Electrolysis (JAMB)

Electrolysis

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Question 7 Report

The salt formed from a weak acid and a strong base hydrolyzes in water to form

A saturated solution

an acidic solution

a buffer solution

an alkaline solution

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Question 8 Report

The gas that can be collected by downward displacement of air is

chlorine

sulphur (IV) oxide

carbon (IV) oxide

ammonia

Separation Of Mixtures And Purification Of Chemical Substances

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Question 9 Report

In the diagram above, Y is

fused CaO

H2O

NaOH

Concentrated H2SO4

Acids, Bases And Salts

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Question 10 Report

The reddish–brown rust on ion roofing sheets consists of

Fe3 + (H2O)6

FeO.H2O

Fe2O3.3H2O

Fe3O4.2H22O

Acids, Bases And Salts

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Question 11 Report

In the laboratory preparation of ethyl ethanoate, the water present in the mixture is removed using a solution of

an hydrous CaCl4

concentrated NaCO4

dilute NaOH

concentrated H4SO4

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Question 12 Report

The reaction of halogens in the presence of sunlight is an example of

oxidation reaction

addition reaction

hydrogenation reaction

substitution reaction

Oxidation And Reduction

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Question 13 Report

A sample of orange juice is found to have a PH of 3.80. What is the concentration of the hydroxide ion in the juice?

1.6

\times

10-4

6.3

\times

10-11

6.3

\times

10-4

1.6

\times

10-11

Acids, Bases And Salts

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Question 14 Report

According to Charle's law, the volume of a gas becomes zero at

−100°c

−273°c

−373°c

0°c

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Question 15 Report

In the laboratory preparation of trioxonitrate (V) acid the nitrogen(iv) oxide formed as a by-product is removed by

further heating

adding concentrated H2SO4

cooling the acid solution with cold water

bubbling air through the acid solution

Acids, Bases And Salts

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Question 16 Report

Ethene is prepared industrially by

Reforming

Polymerization

Distillation

Cracking

Chemical Industry And Environment

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Question 17 Report

A given mass of gas occupies 2dm3 at 300k. At what temperature will its volume be doubled, keeping the pressure constant?

400k

480k

550k

600k

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Question 18 Report

Calculate the amount in moles of silver deposited when 9650C of electricty is passed through a solution of silver salt [= 96500 Cmol-1]

0.05

10.80

10.00

0.10

Electrolysis

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Question 19 Report

The tincture of iodine means iodine dissolved in

ethanol

bromine chloride

chlorine water

water

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Question 20 Report

Ca(OH)2(s) + 2NH4Cl(g) → CaCl2(s) + 2H2O2(l) + X. In the reaction above X is

NO2

NH3

N2O

H2O

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Question 21 Report

The enzyme used in the hydrolysis of starch to dextrin and maltose is

amylase

diastatse

invertase

zymase

Structure Of The Atom (Ghana Only)

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Question 22 Report

The carbon atoms on ethane are

sp2 hybridized

sp3 hybridized

sp4 hybridized

sp hybridized

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Question 23 Report

For a general equation of the nature xP + yQ ? mR + nS, the expression for the equilibrium constant is

k [P]x [Q]y

\frac{[P]^{x} [Q]^{y}}{[R]^{m} [S]^{n}}

\frac{[R]^{m} [S]^{n}}{[P]^{x} [Q]^{y}}

\frac{m [R] n [S]}{x [P] y [Q]}

Chemical Equilibria

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Question 24 Report

Tin is unaffected by air at ordinary temperature due to its

Low melting point

Weak electropositive character

High boiling point

White lustrous appearance

Chemical Combination

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Question 25 Report

CH2S(g) + O2(g) → 2Cn + SO2(g)

What is the change in the oxidation number of copper in the reaction?

0 to + 2

0 to + 1

C + 1 to 0

+ 2 to + 1

Answer Details

In the reactant;

Cu2S

2 Cu - 2(1) = 0

2 Cu = 2

Cu = $\frac{2}{2}$

Cu = +1

In the product, Cu

Cu = O

The oxidation number of Cu in Cu2S and Cu respectively is +1 and 0 respectively

Read lesson note on Oxidation And Reduction (JAMB)

Oxidation And Reduction

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Question 26 Report

The constituent common to duralumin and alnico is

Co

Mn

Al

Mg

Atomic Structure And Bonding

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Question 27 Report

When few drops of concentrated trioxonitrate(V) acid is added to an unknown sample and wanned an intense yellow colouration is observed. The likely functional group present in the sample is

NH3—C—C=O

CHO

CO

CNH2

Acids, Bases And Salts

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Question 28 Report

In the diagram above. X is

SO3

SO2

S

H2S

Separation Of Mixtures And Purification Of Chemical Substances

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Question 29 Report

Aluminium hydroxide is used in the dyeing industry as a

dye

dispersant

salt

mordant

Chemical Kinetics And Equilibrium Systems (Ghana Only)

Chemical Bonds (Ghana Only)

Periodic Chemistry (Ghana Only)

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Question 30 Report

An isomer of C5H12 is

2–ethyl butane

butane

2–methyl butane

2–methyl propane

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Question 31 Report

$ {}^{226}_{88}\mathrm{Ra} \rightarrow {}^{x}_{86}\mathrm{Rn} $ + alpha particle

226

220

227

222

Chemical Combination

Atomic Structure And Bonding

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Question 32 Report

The constituent of air necessary in the rusting process are

O2 and H2O

Ar and CO2

CO2 and H2O

O2 and CO2

Air

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Question 33 Report

Due to the high reactivity of sodium, it is usually stored under

water

mercury

paraffin

phenol

Metals And Their Compounds

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Question 34 Report

The densities of two gases, X and Y are 0.5gdm-3 and 2.0gdm-3 respectively. What is the rate of diffusion of X relative to Y?

0.1

0.5

2.0

4.0

Answer Details

The rate of dimension of a gas inversely proportional to the square root of its molecular mass or its density, which is Graham's Law of diffusion of gas.

R ∝ $\frac{1}{\sqrt{M m}}$ or R ∝ $\frac{1}{\sqrt{D}}$

Dx = 0.5gdm-3, Dy = 2gdm-3

R= $\frac{K}{\sqrt{D}}$

R $\sqrt{D}$ = k

R1 $\sqrt{D_{1}}$ = R1 $\sqrt{D_{2}}$

Rx $\sqrt{D_{x}}$ = Ry $\sqrt{D_{y}}$

$\frac{R_{x}}{R_{y}}$ = $\frac{\sqrt{D_{y}}}{\sqrt{D_{x}}}$

= $\frac{\sqrt{2}}{\sqrt{0.5}}$

= 2.0

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

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Question 35 Report

The general formula of alkanones is

RCHO

R2CO

RCOOH

RCOOR

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Question 36 Report

Calculate the amount in moles of a gas which occupies 10.5 dm3 at 6 atm and 30oC [R = 082 atm dm3 K-1 mol-1]

2.536

1.623

4.736

0.394

Answer Details

For an ideal gas PV = nRT

Amount in moles = n

Volume v = 10.5dm3

Pressure P = 6atm

Temperature T = 30°C + 273 = 303k

R, Gas constant = 0.082 atmdm3k-1 mol

Recall from ideal gas equation

pv = nRT

n = $\frac{R V}{R T}$

n = $\frac{6 \times 105}{0.082 \times 303}$

n= 2.536mol

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

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Question 37 Report

The mass of silver deposited when a current of 10A is passed through a solution of silver salt for 4830s is – (Ag = 108 F = 96500(mol-1)

54.0g

27.0g

13.5g

108.0g

Electrolysis

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Question 38 Report

X(g) + 3Y(g) ---- 2z(g) H = +ve. if the reaction above takes place at room temperature, the G will be

negative

zero

positive

indeterminate

Answer Details

$\begin{array}{cc} Enthalpy Change [ΔH] & Entropy Change [ΔS] & Gibbs free Energy[ΔG] \\ Positive & Positive & depends on T, may be + or - \\ Negative & Positive & always negative \\ Negative & Negative & depends on T, may be + or - \\ Positive & Negative & always positive \end{array}$

?G= ?H ? T?S.
To determine whether ?G will be positive or negative, the value of ?H(change in enthalpy) and ?S (change in entropy) must be given. Likewise the temperature.

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

Read lesson note on Chemical Kinetics And Equilibrium Systems (Ghana Only) (WAEC)