Waec Gce First Series 2022/23 Chemistry Questions with Answers

The hydrolysis of proteins by diluting mineral acids produces

A. sucrose
B. glucose
C. amino acids
D. fatty acids
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Olive.ng exam
Correct Answer: Option C
Which of the following oxide causes acid rain?

A. CO
B. NO
C. H2
O2
D. NO2
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Correct Answer: Option D
Explanation
Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the atmosphere and transported by wind and air currents.

The SO2 and NOX react with water, oxygen and other chemicals to form sulfuric and nitric acids.

The ratio of carbon atoms of hydrogen atoms in a hydrocarbon is 1:2. If its molecular mass is 56, what is its molecular formula?

A. C3
H6
B. C4
H8
C. C2
H4
D. CH2
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Correct Answer: Option B

What is the relative molecular mass of the compound below?

 

What is the relative molecular mass of the compound below [H = 1.0; C = 12.0; O = 16.0] – SchoolNGR

 

[H = 1.0; C = 12.0; O = 16.0]

A. 137
B. 136
C. 64
D. 59
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Correct Answer: Option B

Cathodic protection of metals is based on

A. standard electrode potential of hydrogen
B. its electrical conductivity
C. nature of oxides formed
D. relative tendencies of oxidation
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Correct Answer: Option D

If humid air is polluted by chlorine discharged, the air can be restored by sprinkling

A. solid MnO2
B. acidified KMnO4
C. acidified FeSO4
D. saturated NaCl(aq)
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Olive.ng exam
Correct Answer: Option B
Explanation
l(aq)

The alkanol represented by the structure below is?

Open photo

A. primary and dihydric
B. secondary and monohydric
C. tertiary and dihydric
D. secondary and dihydric
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Olive.ng exam
Correct Answer: Option A

Which of the following pairs of compounds would form a precipitate when their aqueous solutions are mixed?

A. NaCl and KNO3
B. KCL and NaNO3
C. K2
SO4
and BaCl2
D. NH4
NO3
and CO3
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Olive.ng exam
Correct Answer: Option B

Study the graphs below and use them to answer the question below

Open photo

Which of the following illustrates the variation of the rate of evolution of gas from a given length of magnesium ribbon (y-axis) with an increase in the concentration of the added (x-axis)?

A. I
B. II
C. III
D. IV
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Correct Answer: Option A

Study the graphs below and use them to answer the question below

Open photo

Which of the graphs illustrates the variation of the pH of a given volume of strong acid solution (y-axis) with the volume of strong base titrated against its (x-axis)?

A. I
B. II
C. III
D. IV
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Correct Answer: Option A

Study the graphs below and use them to answer the question below

Open photo

Which of the graphs illustrates the variation of the solubility of a salt in water (y-axis), with an increase in temperature (x-axis) if the dissolution process is exothermic?

A. I
B. II
C. III
D. IV
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Correct Answer: Option D

The formation of ethene from dehydration of ethanol can be described as——-

A. an addition reaction
B. an elimination reaction
C. an oxidation reaction
D. a substitution reaction
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Correct Answer: Option B

Which of the following gasses is highly soluble in water at room temperature

A. ammonia
B. carbon (IV) oxide
C. chlorine
D. nitrogen
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Correct Answer: Option A

A molecular of phosphorus is

A. diatomic
B. triatomic
C. tetraatomic
D. monoatomic
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Correct Answer: Option C

The most common method of preparing insoluble salts is by

A. filtration
B. decomposition
C. neutralization
D. double decomposition
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Olive.ng exam
Correct Answer: Option D

What number of moles of oxygen would exert a pressure of 10 atm at 320 K in an 8.2 dm2
cylinder?

[R = 0.082 atm dm3
mol−1
K−1
]

 

A. 0.32
B. 1.56
C. 3.13
D. 31.25
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Correct Answer: Option C

The basic property of salts used as drying agents is by?

A. efforescence
B. high melting point
C. hygroscopy
D. low solubility
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Correct Answer: Option C
Explanation
Hygroscopic substances are used to keep products dry or to remove water from an area. They are commonly used in desiccators
Some common examples of hygroscopic substances include: Sodium chloride. Zinc chloride. Calcium chloride

What would be observed when aqueous ammonia is added in drops and then in excess to a solution of copper(II) ions?

A. blue precipitate is formed which is soluble in excess ammonia
B. brick red precipitate is produced which is insoluble in excess ammonia
C. which precipitate is formed which is excess in ammonia
D. green precipitate is formed which is insoluble in excess ammonia
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Olive.ng exam
Correct Answer: Option A

When CuSO4(aq)
is added to Pb(NO3

)2(aq)

A. there would be no visible change
B. a blue precipitate would be formed
C. the resulting solution would become colourless
D. a white precipitate would be formed
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Correct Answer: Option D

Consider the structure below

Open photo

How many carbon atoms does the parent chain contain?

A. 5
B. 4
C. 3
D. 2
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Correct Answer: Option A

Under which conditions of pressure (p) and temperature (T) would the volume of an inflated ballon increase? When

A. P and T are increased
B. both T and P are decreased
C. T is increased and P is decreased
D. T is decreased and P is increased
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Correct Answer: Option C

The collision between ideal gas molecules are considered to be perfectly elastic because

A. they collide without losing energy
B. they move randomly in a straight line
C. their average kinetic energy is variable
D. the distance between them is large compared to their size
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Correct Answer: Option A

Elements with high ionization energies would——-

A. lose electrons easily
B. have large atomic radii
C. have high effective nuclear charges
D. have low atomic numbers

Correct Answer: Option C

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