JAMB UTME - Chemistry - 2019

Tazama Jibu

Swali 3 Ripoti

Which of the following reactions is an oxidation process?

2H

^{+}

+ 2e

^{-}

\to

H

_{2}

2O

^{2 -}

+ 4e

^{-}

\to

O

_{2}

OCl

^{-}

+ H

_{2}

O + 2e

^{-}

\to

2OH

^{-}

+ Cl

^{-}

Cl + e

^{-}

\to

Cl

^{-}

Oxidation And Reduction

Tazama Jibu

Swali 4 Ripoti

The electronic configuration of element Z is 1s $^{2}$ 2s $^{2}$ 2p $^{6}$ 3s $^{2}$ 3p $^{1}$ . What is the formula of the compound formed between Z and tetraoxosulphate (VI) ion.

Z

_{3}

(SO

_{4}

)

_{2}

ZSO

_{4}

Z

_{2}

SO

_{4}

Z

_{2}

(SO

_{4}

)

_{3}

Maelezo ya Majibu

Z = 1s $^{2}$ 2s $^{2}$ 2p $^{6}$ 3s $^{2}$ 3p $^{1}$
$∴$ We have Z $^{3 +}$ and SO $_{4}^{2 -}$
The reaction : Z $^{3 +}$ + SO $_{4}^{2 -}$ $\to$ Z $_{2}$ (SO $_{4}$ ) $_{3}$ .

Soma maelezo ya somo kwenye Atomic Structure And Bonding (JAMB)

Tazama Jibu

Swali 5 Ripoti

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)

Tazama Jibu

Swali 6 Ripoti

Which of the following metals is the most essential in the regulation of blood volume, blood pressure and osmotic equilibrium?

Zinc

Manganese

Sodium

Iron

Metals And Their Compounds

Tazama Jibu

Swali 7 Ripoti

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

Tazama Jibu

Swali 8 Ripoti

A radioactive nucleus has a half-life of 20 years, starting with 100,000 particles, how many particles will be left exactly at the end of 40 years

75,000 particles

35,000 particles

25,000 particles

50,000 particles

Tazama Jibu

Swali 9 Ripoti

The IUPAC name for CH $_{3}$ CH $_{2}$ COOCH $_{2}$ CH $_{3}$ is

methylpropanoate

ethylethanoate

ethylpropanoate

methylethanoate

Tazama Jibu

Swali 10 Ripoti

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)

Tazama Jibu

Swali 11 Ripoti

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

Tazama Jibu

Swali 12 Ripoti

The heat of formation of ethene, C $_{2}$ H $_{4}$ is 50 kJmol $^{- 1}$ , and that of ethane, C $_{2}$ H $_{6}$ is -82kJmol $^{- 1}$ . Calculate the heat evolved in the process:

C $_{2}$ H $_{4}$ + H $_{2}$ $\to$ C $_{2}$ H $_{6}$

-122kJ

-132kJ

-88kJ

-60kJ

Energy Changes

Tazama Jibu

Swali 13 Ripoti

The two ions responsible for hardness in water are

Ca

^{2 +}

and / or Mg

^{2 +}

K

^{+}

and / or Mg

^{2 +}

Ca

^{2 +}

and / or Li

^{+}

Ca

^{2 +}

and / or Na

^{+}

Solubility

Water

Tazama Jibu

Swali 14 Ripoti

The following are isoelectronic ions except

Na

^{+}

Mg

^{2 +}

Si

^{2 +}

O

^{2 +}

Maelezo ya Majibu

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.

Soma maelezo ya somo kwenye Acids, Bases And Salts (Nigeria Only) (WAEC)

Soma maelezo ya somo kwenye Atomic Structure And Bonding (JAMB)

Acids, Bases And Salts (Nigeria Only)

Tazama Jibu

Swali 15 Ripoti

Which of the following statements does not show Rutherford's account of Nuclear Theory? An atom contains a region

which contains protons and neutrons

which is positively charged

which is massive and can cause deflection of a few projectiles

which is very large and in which close to 98% of projectiles pass undeflected

Tazama Jibu

Swali 16 Ripoti

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

propylmethanoate

ethylpropanoate

methyl ethanoate

methyl propanoate

Tazama Jibu

Swali 17 Ripoti

A synthetic rubber is obtained from the polymerization of

neoprene

isoprene

butandiene

propylene

Basic Biochemistry And Synthetic Polymers

Tazama Jibu

Swali 18 Ripoti

Hydrocarbons which will react with Tollen's reagent conform to the general formula

C

_{n}

H

_{2 n}

C

_{n}

H

_{2 n + 2}

C

_{n}

H

_{2 n - 2}

C

_{n}

H

_{2 n + 1}

OH

Tazama Jibu

Swali 19 Ripoti

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

Tazama Jibu

Swali 20 Ripoti

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

Tazama Jibu

Swali 21 Ripoti

Which of the following conditions will most enhance the spontaneity of a reaction?

Δ

H is negative and greater than T

Δ

S

Δ

H is negative and

Δ

S = 0

Δ

H is positive and less than T

Δ

S

Δ

H is positive and equal to T

Δ

S

Tazama Jibu

Swali 22 Ripoti

The IUPAC nomenclature of the compound

H $_{3}$ C - CH(CH $_{3}$ ) - CH(CH $_{3}$ ) - CH $_{2}$ - CH $_{3}$

3,4- dimethylhexane

2,3- dimethyl pentane

2- ethyl hexane

2,3- dimethylhexane

Tazama Jibu

Swali 23 Ripoti

The reaction $2 H_{2} S + S O_{2} \to 3 S + 2 H_{2} O$ is

not a redox reaction because there is no oxidant in the reaction

not a redox reaction because there is no reductant in the reaction

a redox reaction in which H

_{2}

S is the oxidant and SO

_{2}

is the reductant

a redox reaction in which SO

_{2}

is the oxidant and H

_{2}

S is the reductant

Tazama Jibu

Swali 24 Ripoti

What volume of 0.100M sodium trioxonitrate (V) solution contains 5g of solute.

[Na = 23, N = 14, O = 16]

1.7 litres

0.420 litres

0.588 litres

2.35 litres

Tazama Jibu

Swali 25 Ripoti

Na $_{2}$ CO $_{3}$ + 2HCl $\to$ 2NaCl + H $_{2}$ O + CO $_{2}$

The indicator most suitable for this reaction should have a pH equal to

5

7

3

9

Acids, Bases And Salts

Tazama Jibu

Swali 26 Ripoti

In the reaction:

M + N → P

ΔH = +Q kJWhich of the following would increase the concentration of the product?

Adding a suitable catalyst

Increasing the concentration of P

Increasing the temperature

Decreasing the temperature

Tazama Jibu

Swali 27 Ripoti

Which of the following describes the chemical property of acids?

None of the above

Acid + XCO

_{3}

\to

Salt + H

_{2}

O + NH

_{3}

Acid + NaOH

\to

Normal salt + CO

_{2}

Acid + X

_{n}

CO

_{3}

\to

Salt + H

_{2}

O + CO

_{2}

Acids, Bases And Salts

Tazama Jibu

Swali 28 Ripoti

If acidified Potassium Dichromate(VI) (K $_{2}$ Cr $_{2}$ O $_{7}$ ) acts as oxidizing agent, color changes from

yellow to green

orange to green

yellow to red

orange to red

Oxidation And Reduction

Tazama Jibu

Swali 29 Ripoti

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

atomic numbers

metallic character

mass number

relative atomic mass

Tazama Jibu

Swali 30 Ripoti

An element Z contains 80% of $_{8}^{16}$ Z and 20% of $_{8}^{18}$ Z. Its relative atomic mass is

16.2

17.6

16.0

16.4

Maelezo ya Majibu

R.A.M of Z = $16 (\frac{80}{100}) + 18 (\frac{20}{100})$
= $12.8 + 3.6$
= 16.4

Soma maelezo ya somo kwenye Separation Of Mixtures And Purification Of Chemical Substances (JAMB)

Soma maelezo ya somo kwenye Atomic Structure And Bonding (JAMB)

Separation Of Mixtures And Purification Of Chemical Substances

Tazama Jibu

Swali 31 Ripoti

SO $_{3}$ is not directly dissolved in water in the industrial preparation of H $_{2}$ SO $_{4}$ by the contact process because

SO

_{3}

is an acidic gas

Acid is usually added to water and not water to acid

The reaction between SO

_{3}

and water is violently exothermic

SO

_{3}

does not dissolve readily in water

Acids, Bases And Salts

Tazama Jibu

Swali 32 Ripoti

Which of the following pollutants will lead to the depletion of ozone layer?

chlorofluorocarbon

carbon (ii) oxide

hydrogen sulphide

sulphur (iv) oxide

Environmental Pollution

Tazama Jibu

Swali 33 Ripoti

In the reaction between sodium hydroxide and tetraoxosulphate (VI) solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralize 10cm $^{3}$ of 1.25 molar tetraoxosulphate (vi) acid?

25cm

^{3}

10cm

^{3}

20cm

^{3}

50cm

^{3}

Maelezo ya Majibu

Equation of reaction : 2NaOH + H $_{2}$ SO $_{4}$ → Na $_{2}$ SO $_{4}$ + 2H $_{2}$ O

Concentration of a base, CB = 0.5M

Volume of acid, V $_{A}$ = 10cm $^{3}$

Concentration of an acid, C $_{A}$ = 1.25M

Volume of base, V $_{B}$ = ?

Recall:
$\frac{C_{A} V_{A}}{C_{B} V_{B}} = \frac{n_{A}}{n_{B}}$ ... (1)
N.B: From the equation,
$\frac{n_{A}}{n_{B}} = \frac{1}{2}$

From (1)
$\frac{1.25 \times 10}{0.5 \times V_{B}} = \frac{1}{2}$
$\frac{12.5}{0.5 V_{B}} = \frac{1}{2}$
25 = 0.5V $_{B}$

VB = 50.0 cm $^{3}$

Soma maelezo ya somo kwenye Stoichiometry And Chemical Reactions (WAEC)

Tazama Jibu

Swali 34 Ripoti

A secondary alkanol can be oxidized to give an

alkanone

alkyne

alkanoic acid

alkanal

Tazama Jibu

Swali 35 Ripoti

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

-3, +3

+5

-3, +5

-3

Maelezo ya Majibu

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.

Soma maelezo ya somo kwenye Oxidation And Reduction (JAMB)

Oxidation And Reduction

Tazama Jibu

Swali 36 Ripoti

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}}

Maelezo ya Majibu

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

Soma maelezo ya somo kwenye Kinetic Theory Of Matter And Gas Laws (JAMB)