JAMB UTME - Chemistry - 2019

Chemical Kinetics And Equilibrium Systems (Ghana Only)

Periodic Chemistry (Ghana Only)

Wo Idahun

Ajụjụ 3 Ripọtì

Elements in the periodic table are arranged in the order of their

atomic numbers

metallic character

mass number

relative atomic mass

Wo Idahun

Ajụjụ 4 Ripọtì

Which of the following pairs cannot be represented with a chemical formula?

air and bronze

bronze and sodium chloride

copper and sodium chloride

caustic soda and washing soda

Metals And Their Compounds

Wo Idahun

Ajụjụ 5 Ripọtì

The velocity, V of a gas is related to its mass, M by (k = proportionality constant)

V =

\frac{k}{M}

V =

\frac{k}{M^{\frac{1}{2}}}

V =

k M^{2}

V =

(\frac{k}{M})^{\frac{1}{2}}

Akọwa Nkọwa

Recall:
V = $\sqrt{\frac{3 R T}{M}}$
$∴ V \propto \frac{1}{\sqrt{M}}$
$V = \frac{k}{\sqrt{M}}$
V = $\frac{k}{M^{\frac{1}{2}}}$

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Wo Idahun

Ajụjụ 6 Ripọtì

The cost of discharging 6.0g of a divalent metal, X from its salt is ₦12.00. What is the cost of discharging 9.0g of a trivalent metal, Y from its salt under the same condition?

[X = 63, Y = 27, 1F = 96,500C]

N12.00

N27.00

N63.00

N95.00

Akọwa Nkọwa

For X: X $^{2 +}$ + 2e $^{-}$ $\to$ X
2F = 63g
xF = 6g
x = $\frac{6 \times 2}{63} = \frac{4}{21} F$
$\frac{4}{21}$ F = N12.00
1F = $\frac{12}{\frac{4}{21}}$
= N63.00
1F is equivalent to N63.00.
For Y: Y $^{3 +}$ + 3e $^{-}$ $\to$ Y
3F = 27g
xF = 9g
x = $\frac{3 \times 9}{27}$
= 1F
1F = N63.00

Gụọ akwụkwọ nkuzi na Chemical Combination (JAMB)

Chemical Combination

Wo Idahun

Ajụjụ 7 Ripọtì

The IUPAC nomenclature of the compound

$\mathrm{H_3C - CH(CH_3) - CH(CH_3) - CH_2 - CH_3}$

3,4- dimethylhexane

2,3- dimethyl pentane

2- ethyl hexane

2,3- dimethylhexane

Wo Idahun

Ajụjụ 8 Ripọtì

2-methylprop-1-ene is an isomer of

3-methyl but-1-ene

2-methyl but-1-ene

but-2-ene

pent-2-ene

Wo Idahun

Ajụjụ 9 Ripọtì

A secondary alkanol can be oxidized to give an

alkanone

alkyne

alkanoic acid

alkanal

Wo Idahun

Ajụjụ 10 Ripọtì

The shapes of water, ammonia, carbon (iv) oxide and methane are respectively

linear, tetrahedral, angular and pyramidal

angular, pyramidal, linear and tetrahedral

pyramidal, linear, tetrahedral and angular

tetrahedral, angular, pyramidal and linear

Wo Idahun

Ajụjụ 11 Ripọtì

Which important nitrogen-containing compound is produced in Haber's process?

NH

_{3}

NO

_{2}

NO

HNO

_{3}

Wo Idahun

Ajụjụ 12 Ripọtì

When chlorine water is exposed to bright sunlight, the following products are formed

HCl

_{(a q)}

and Cl

_{2}

HOCl

_{(a q)}

and Cl

_{2}

HCl

_{(a q)}

and O

_{2}

HOCl

_{(a q)}

and O

_{2}

Chemistry Of Carbon Compounds (Ghana Only)

Wo Idahun

Ajụjụ 13 Ripọtì

The following are isoelectronic ions except

Na

^{+}

Mg

^{2 +}

Si

^{2 +}

O

^{2 +}

Akọwa Nkọwa

Two or more ions are said to be isoelectronic if they have the same electronic structure and the same number of valence electrons.
Na $^{+}$ = 10 electrons = 2, 8
Mg $^{2 +}$ = 10 electrons = 2,8
O $^{2 -}$ = 10 electrons = 2,8
Si $^{2 +}$ = 12 electrons = 2,8,2
$⟹$ Si $^{2 +}$ is not isoelectronic with the rest.

Gụọ akwụkwọ nkuzi na Acids, Bases And Salts (Nigeria Only) (WAEC)

Gụọ akwụkwọ nkuzi na Atomic Structure And Bonding (JAMB)

Acids, Bases And Salts (Nigeria Only)

Wo Idahun

Ajụjụ 14 Ripọtì

A compound contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen. If the molar mass of the compound is 180. Find the molecular formula.

[H = 1, C = 12, O = 16]

C

_{3}

H

_{6}

O

_{3}

C

_{6}

H

_{6}

O

_{3}

C

_{6}

H

_{12}

O

_{6}

CH

_{2}

O

Wo Idahun

Ajụjụ 15 Ripọtì

How many alkoxyalkanes can be obtained from the molecular formula $ \mathrm{C_4H_{10}O} $?

4

2

1

3

Acids, Bases And Salts (Nigeria Only)

Chemical Equilibria

Wo Idahun

Ajụjụ 16 Ripọtì

A synthetic rubber is obtained from the polymerization of

neoprene

isoprene

butandiene

propylene

Basic Biochemistry And Synthetic Polymers

Wo Idahun

Ajụjụ 17 Ripọtì

Elements X and Y have electronic configurations $1s^2 2s^2 2p^4$ and $1s^2 2s^2 2p^6 3s^2 3p^1$ respectively. When they combine, the formula of the compound formed is

XY

X

_{2}

Y

_{2}

X

_{3}

X

_{2}

Y

_{3}

Wo Idahun

Ajụjụ 18 Ripọtì

The hybridization in the compound $ \mathrm{CH_3-CH_2-C\equiv H} $ is

sp

^{3}

and sp

sp

^{2}

sp

^{3}

and sp

^{2}

Akọwa Nkọwa

The hybridization in a and b is sp $^{3}$ hybridization while in c and d is sp hybridization.

Wo Idahun

Ajụjụ 19 Ripọtì

Which of the following is the best starting material for the preparation of oxygen? Heating of trioxonitrate (v) with

Pb

Zn

Ca

Na

Chemical Combination

Wo Idahun

Ajụjụ 20 Ripọtì

At 27°C, 58.5g of sodium chloride is present in 250cm$^3$ of a solution. The solubility of sodium chloride at this temperature is?

(molar mass of sodium chloride = 111.0gmol$^{-1}$)

2.0 moldm

^{- 3}

0.25 moldm

^{- 3}

1.0 moldm

^{- 3}

0.5 moldm

^{- 3}

Akọwa Nkọwa

Given the Mass of the salt = 58.5g
Volume = 250 cm $^{3}$ = 0.25 dm $^{3}$
Mass concentration = $\frac{M a s s}{V o l u m e}$
= $\frac{58.5}{0.25}$ = 234 gdm $^{- 3}$
Solubility (in moldm $^{- 3}$ = $\frac{234}{111}$
= 2.11 moldm $^{- 3}$
$≊$ 2.0 moldm $^{- 3}$

Gụọ akwụkwọ nkuzi na Solubility Of Substances (Ghana Only) (WAEC)

Solubility Of Substances (Ghana Only)

Wo Idahun

Ajụjụ 21 Ripọtì

Which process(es) is/are involved in the turning of starch iodide paper blue-black by chlorine gas?

chlorine attacks the starch to give the blue-black color

chlorine attacks the iodide ion to give the blue-black color

chlorine oxidizes the iodide ion to produce iodine which attacks the starch to give the blue-black color

iodine attacks the starch to give the blue-black color

Energy And Energy Changes

Wo Idahun

Ajụjụ 22 Ripọtì

The part of the total energy of a system that accounts for the useful work done in a system is known as

Enthalpy change

None of the above

Gibb's free energy

Entropy

Energy Changes

Wo Idahun

Ajụjụ 23 Ripọtì

A solution X, on mixing with $ \mathrm{AgNO_3} $ solution gives a white precipitate soluble in aqueous $ \mathrm{NH_3} $, a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain

Al

^{3 +}

, Cl

^{-}

Hg

^{+}

, SO

_{4}^{2 -}

Pb

^{2 +}

, Cl

^{-}

Ag

^{+}

, SO

_{4}^{2 -}

Chemistry Of Carbon Compounds (Ghana Only)

Wo Idahun

Ajụjụ 24 Ripọtì

Which two gases can be used for the demonstration of the fountain experiment?

SO

_{3}

and NH

_{3}

SO

_{2}

and NH

_{3}

HCl and NH

_{3}

SO

_{2}

and HCl

Wo Idahun

Ajụjụ 25 Ripọtì

Which of the following properties increases from left to right along the period but decreases down the group in the Periodic Table?

I. Atomic Number ii. Ionization energy iii. Metallic character iv. Electron affinity

ii and iii only

ii and iv only

iii and iv only

i and ii only

Periodic Chemistry (Nigeria Only)

Wo Idahun

Ajụjụ 26 Ripọtì

Which of the following is a set of neutral oxides?

N

_{2}

O, H

_{2}

O, CO

N

_{2}

O, SO

_{2}

, CO

N

_{2}

O, Na

_{2}

O, ZnO

N

_{2}

O, SO

_{3}

, NO

Oxidation And Reduction

Wo Idahun

Ajụjụ 27 Ripọtì

The emission of two successive beta particles from the nucleus $ {}^{32}_{15}\mathrm{P} $ will produce

_{14}^{30}

Si

_{13}^{32}

Al

_{17}^{32}

Cl

_{16}^{32}

S

Akọwa Nkọwa

Explanation:

_{15}^{32}

P

\to

2

_{- 1}^{0}

e +

_{b}^{a}

X
32 = 2(0) + a
a = 32
15 = 2(-1) + b
b = 15 + 2
b = 17

∴

_{b}^{a}

X =

_{17}^{32}

Cl

Gụọ akwụkwọ nkuzi na Structure Of The Atom (WAEC)

Structure Of The Atom

Wo Idahun

Ajụjụ 28 Ripọtì

Which of the following represents the kind of bonding present in ammonium chloride?

ionic only

covalent only

ionic and dative covalent

dative covalent

Wo Idahun

Ajụjụ 29 Ripọtì

The molecular shape and bond angle of water are respectively

linear, 180°

bent, 109.5°

tetrahedral, 109.5°

bent, 105°

Wo Idahun

Ajụjụ 30 Ripọtì

The IUPAC name of the compound $\mathrm{CF_3CHBrCl}$ is

2-chloro-2-bromo-1,1,1-trifluoroethane

2-bromo-2-chloro-1,1,1-trifluoroethane

1-bromo-1-chloro-2,2,2-trifluoroethane

1,1,1-trifluoro-2-bromo-2-chloroethane

Periodic Chemistry (Ghana Only)

Wo Idahun

Ajụjụ 31 Ripọtì

Consider the reaction: $ \mathrm{A + 2B(g) \rightleftharpoons 2C + D(g)} $ ($ \Delta H = +\mathrm{ve} $)

What will be the effect of decrease in temperature on the reaction?

Rate of backward reaction will increase

The equilibrium constant will shift

Rates of forward and backward reactions are not affected

Rate of forward reaction will increase

Chemical Equilibria

Wo Idahun

Ajụjụ 32 Ripọtì

A certain hydrocarbon on complete combustion at s.t.p produced 89.6dm³ of CO₂ and 54g of water. The hydrocarbon should be

C

_{6}

H

_{6}

C

_{4}

H

_{10}

C

_{5}

H

_{10}

C

_{4}

H

_{6}

Wo Idahun

Ajụjụ 33 Ripọtì

When the end alkyl groups of ethyl ethanoate are interchanged, the compound formed is

propylmethanoate

ethylpropanoate

methyl ethanoate

methyl propanoate

Wo Idahun

Ajụjụ 34 Ripọtì

The combustion of carbon(ii)oxide in oxygen can be represented by equation.

$2\mathrm{CO} + \mathrm{O}_2\ ?\ 2\mathrm{CO}_2$

Calculate the volume of the resulting mixture at the end of the reaction if $50\mathrm{cm}^3$ of carbon(ii)oxide was exploded in $100\mathrm{cm}^3$ of oxygen

75cm

^{3}

125cm

^{3}

100cm

^{3}

50cm

^{3}

Stoichiometry And Chemical Reactions

Wo Idahun

Ajụjụ 35 Ripọtì

$200\text{cm}^3$ of $0.50\text{mol}/\text{dm}^3$ solution of calcium hydrogen trioxocarbonate (IV) is heated. The maximum weight of solid precipitated is

10g

25g

20g

15g

Akọwa Nkọwa

To solve this problem, we need to use the concept of stoichiometry and the solubility product constant (Ksp) of calcium hydrogen trioxocarbonate (IV). First, we need to write the balanced equation for the reaction that occurs when the solution of calcium hydrogen trioxocarbonate (IV) is heated: Ca(HCO3)2(s) → CaCO3(s) + H2O(g) + CO2(g) From the balanced equation, we can see that 1 mole of calcium hydrogen trioxocarbonate (IV) produces 1 mole of calcium carbonate. Therefore, we need to determine the number of moles of calcium hydrogen trioxocarbonate (IV) in the solution: Number of moles = concentration x volume Number of moles = 0.50 mol/dm³ x 0.2 dm³ Number of moles = 0.1 mol Since 1 mole of calcium hydrogen trioxocarbonate (IV) produces 1 mole of calcium carbonate, the number of moles of calcium carbonate produced will also be 0.1 mol. Next, we need to use the solubility product constant (Ksp) of calcium carbonate to determine the maximum amount of solid that can be precipitated: Ksp = [Ca²⁺][CO3²⁻] Ksp = 3.3 x 10⁻⁹ (at 25°C) At the maximum amount of solid precipitated, all the calcium carbonate formed will have precipitated, and the concentration of calcium ions and carbonate ions will be equal. Therefore, we can assume that the concentration of calcium ions and carbonate ions is both x. Substituting into the Ksp expression: Ksp = x² 3.3 x 10⁻⁹ = x² x = 5.74 x 10⁻⁵ mol/dm³ The mass of calcium carbonate precipitated can now be calculated: Mass = number of moles x molar mass Mass = 0.1 mol x 100.1 g/mol Mass = 10.01 g Therefore, the maximum weight of solid precipitated is approximately 10 g. Note that this calculation assumes that all the calcium carbonate precipitated as a solid, which may not always be the case in a real-world experiment. Additionally, this calculation does not take into account any losses due to filtration or other experimental errors.

Gụọ akwụkwọ nkuzi na Kinetic Theory Of Matter And Gas Laws (JAMB)

Wo Idahun

Ajụjụ 36 Ripọtì

Which quantum divides shells into orbitals?

Spin

Principal

Azimuthal

Magnetic

Wo Idahun

Ajụjụ 37 Ripọtì

The oxidation state(s) of nitrogen in ammonium nitrite is/are

-3, +3

+5

-3, +5

-3

Akọwa Nkọwa

Ammonium nitrite = NH $_{4}$ NO $_{2}$
NH $_{4}^{+}$ : Let the oxidation number of Nitrogen = x
x + 4 = 1 $⟹$ x = 1 - 4
x = -3
NO $_{2}^{-}$ : x - 4 = -1
x = -1 + 4 $⟹$ x = +3.
The oxidation numbers for Nitrogen in Ammonium Nitrite = -3, +3.

Gụọ akwụkwọ nkuzi na Oxidation And Reduction (JAMB)

Oxidation And Reduction

Wo Idahun

Ajụjụ 38 Ripọtì

The heat of formation of ethene, $ \mathrm{C_2H_4} $ is 50 $ \mathrm{kJmol^{-1}} $, and that of ethane, $ \mathrm{C_2H_6} $ is -82$ \mathrm{kJmol^{-1}} $. Calculate the heat evolved in the process:

\[ \mathrm{C_2H_4 + H_2 \rightarrow C_2H_6} \]

-122kJ

-132kJ

-88kJ

-60kJ

Energy Changes

Stoichiometry And Chemical Reactions

Wo Idahun

Ajụjụ 39 Ripọtì

If the cost of electricity required to discharge 10g of an ion $X^{3+}$ is N20.00, how much would it cost to discharge 6g of ion $Y^{2+}$?

[1 faraday = 96,500C, atomic masses are X = 27, Y = 24]

N10.00

N6.00

N20.00

N9.00

Akọwa Nkọwa

X $^{3 +}$ + 3e $^{-}$ $\to$ X
3F = 27g
xF = 10g
$\frac{x}{3} = \frac{10}{27} ⟹ x = \frac{10}{9} F$
$\frac{10}{9}$ F $\equiv$ N20.00
1F is equivalent to x
$\frac{1}{\frac{10}{9}} = \frac{x}{20}$
$\frac{9}{10} = \frac{x}{20} ⟹ x = N 18.00$
1F is equivalent to N18.00.
Y $^{2 +}$ + 2e $^{-}$ $\to$ Y
2F = 24g
xF = 6g
x = $\frac{6 \times 2}{24} = \frac{1}{2} F$
1F = N18.00
$\frac{1}{2}$ F = $\frac{1}{2} \times N 18.00$
= N9.00

Wo Idahun

Ajụjụ 40 Ripọtì

Which of the following factors will speed up the rate of evolution of carbon (iv) oxide in the reaction below?

$2HCl + CaCO_3 \rightarrow CaCl_2 + H_2O + CO_2$

Increasing the concentration of the acid

Increasing the surface area of CaCO

_{3}

A and B

Reducing the concentration of the acid