2021 WASSCE CHEMISTRY OBJECTIVES
1.
The hydrolysis of proteins by dilute mineral acids produces
A. sucrose
B. glucose
C. amino acids
D. fatty acids
2.
Which of the following oxides causes acid rain?
A. CO
B. NO
C. H2O
D. NO2
3.
The ratio of carbon atoms to hydrogen atoms in a hydrocarbon is 1:2. If its molecular mass is 56, what is its
molecular formula?
A. C3H6
B. C4H8
C. C2H4
D. CH2
4.
What is the relative molecular mass of the compound below?
[H= 1.0; C=12.0; O=16.0]
A. 137
B. 136
C. 64
D. 59
5.
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
6.
If humid air is polluted by chlorine discharge, the air can be restored by sprinkling
A.
solid MnO2
B.
acidified KMnO4
C.
acidified FeSO4
D.
saturated NaCl(aq)
7.
The alkanols represented by the structure below is
A. primary and dihydric
B. secondary and monohydric
C. tertiary and dihydric
D. secondary and dihydric
8.
Which of the following pairs of compounds will form a precipitate when their aqueous solutions are mixed?
A. NaCl and KNO3
B. KCl and NaNO3
C. K2SO4 and BaCl2
D. NH4NO3 and Na2CO3
A.
C.
B.
D.
9.
Which of the graphs, in the options, illustrate the variation of the rate of evolution of a gas from a given
length of magnesium ribbon (y-axis) with increase in the concentration of the acid added (x-axis)?
A.
B.
C.
D.
A
B
C
D
10.
Which of the graphs illustrate the variation of the pH of a given volume of strong acid solution (y-axis) with
the volume of strong base titrated against it (x-axis)?
A.
B.
C.
D.
A
B
C
D
11.
Which of the graphs illustrate the variation of the solubility of a salt in water (y-axis) with increase in
temperature (x-axis), if the dissolution process is exothermic?
A.
B.
C.
D.
A
B
C
D
12.
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
13.
Which of the following gasses is highly soluble in water at room temperature?
A. ammonia
B. carbon (IV) oxide
C. chlorine
D. nitrogen
14.
A molecule of phosphorus is
A.
diatomic
B.
triatomic
C.
tetra atomic
D.
monoatomic
15.
The most common method of preparing insoluble salt is by
A.
filtration
B.
decomposition
C.
neutralization
D.
double decomposition
16.
What number of moles of oxygen will exert a pressure of 10 atmosphere at 320K in an 8.2dm 3 cylinder?
[R = 0.082atmdm3/mol/K]
A.
0.32
B.
1.56
C.
3.13
D.
31.25
17.
The basic property of salt used as drying agent is
A.
efflorescence
B.
high melting point
C.
hydroscopy
D.
low solubility
18.
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. white precipitate is formed which is soluble in excess ammonia
D. green precipitate is formed which is insoluble in excess ammonia
19.
When CuSO4(aq) is added to Pb(NO3)2(aq)
A. there will be no visible change
B. a blue precipitate will be formed
C. the resulting solution will become colourless
D. a white precipitate will be formed
20.
Consider the structure below:
How many carbon atoms does the parent chain contain?
A. 5
B. 4
C. 3
D. 2
21.
Under which conditions of pressure (P) and temperature (T) would the volume of an inflated balloon
increase? When
A. both T and P 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
22.
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. the average kinetic energy is variable
D. the distance between them is large compared to their sizes
23.
Elements with high ionization energy would
A. lose electrons easily
B. have large atomic radii
C. have effectively nuclear charges
D. have low atomic number
24.
Which of the following statements about group VII elements is correct?
A. They are present in the same physical state
B. They are strong reducing agent
C. Their reactivity decreases down the group
D. They exist as monoatomic molecule
Consider the diagram and use it to answer the question below
25.
Which of the following cell notations represents the diagram?
A. B2+/B//A/A3+
B. A3+/A//B/B2+
C. B/B2+//A/A3+
D. A/A3+//B2+/B
26.
Which of the following half-reaction equations represent the reaction at the cathode?
A. A3+(aq) + 3e–→ A(s)
B. B2+(aq) + 2e– → B(s)
C. A(s) → A3+(aq) + 3e–
D. B(s) → B2+(aq) + 2e–
27.
The reactivity of fluorine is high because of
A. its high electronegativity
B. the small size of the fluorine atom
C. the availability of d-orbitals
D. the strong F-F bond
28.
How many coulombs of electricity would liberate 1.08g of Ag from a solution of silver salt?
[Ag = 108.0; F = 96500 C]
A. 96500 C
B. 9650 C
C. 965 C
D. 9.65 C
29.
The Bohr model of the atom proposed the existence of
A. the nucleus
B. electron shells
C. nucleons
D. neutrons
30.
At 25 oC evaporation of a 100cm3 solution of K2CO3 to dryness gave 14g of the salt. What is the solubility of
K2CO3 at 25°C?
[K2CO3 = 138]
A. 0.01 mol/dm3
B. 0.101 mol/dm3
C. 1.01 mol/dm3
D. 10.0 mol/dm3
31.
Student X titrated 25cm3 of Na2CO3 with 0.1 mol/dm3 HCl using methyl orange as indicator. Student Y
carried out the same exercise but he used phenolphthalein as indicator.
Which of the following statements about the titration is true?
A. Hydrogen chloride gas was released in the reaction in both titration
B. The titre values obtained by the titrations are equal
C. The titre value obtained by X is twice that of Y
D. The titre value obtained by Y is twice that of X
32.
What is the concentration of a solution which contains 0.28g of KOH in 100cm3 of solution?
[KOH= 56]
A. 0.01 mol/dm3
B. 0.05 mol/dm3
C. 0.10 mol/dm3
D. 0.50 mol/dm3
33.
What is the empirical formula of a hydrocarbon containing 0.160mol of carbon and 0.640 moles of
hydrogen?
A. CH2
B. CH3
C. CH4
D. C2H4
34.
Which of the following species has the largest ionic radius?
A. S2B. Cl–
C. K+
D. Ca2+
35.
Which of the following statements is correct about ionization energy?
A. Decreases across the period
B. Results in the formation of an anion
C. Causes metallic nuclei to disintegrate
D. Decreases down the group
36.
Potassium trioxonitrate (V) can be obtained from its solution by
A. Distillation
B. Evaporation
C. Crystallization
D. Filtration
37.
An element, Q, contains 69% of 63Q and 31% of 65Q. What is the relative atomic mass of Q?
A. 63.0
B. 63.6
C. 65.0
D. 69.0
38.
The following ions have the same electron configuration except 8O, 12Mg, 13Al, 17Cl.
A. Cl–
B. O2C. Mg2+
D. Al3+
39.
The region around the nucleus where electrons can be located is called
A. spectra
B. an orbital
C. a quanta
D. a field
40.
Protons and electrons are fundamentals particles because they
A. are invisible
B. have different charges
C. are the lightest particles
D. are found in all matter
Consider the following energy profile diagram and use it to answer the question that follows
41.
The activation energy of the reaction is
A. EA
B. EB
C. EC
D. ED
42.
The enthalpy change of the reaction is
A. EA
B. EB
C. EC
D. ED
43.
The energy profile diagram illustrates
A. an endothermic reaction
B. an exothermic reaction
C. a spontaneous reaction
D. a redox reaction
44.
How many molecules of oxygen would occupy a volume of 2.24 cm3 at S.t.p.?
A. 3.01 x 1020
B. 3.01 x 1027
C. 6.02 x 1019
D. 6.02 x 1027
45.
The isotopes of neon are represented by the symbols 20xNe, 21yNe and 22zNe. The relationship between x, y
and z is
A. x > y > z
B. x < y < z
C. x = y = z
D. x < z < y
46.
Which of the following pairs of molecules form hydrogen bond?
A. C2H5OH and CH3OH
B. CH3OH and H2
C. H2S and CH4
D. NH3 and SO2
47.
Which of the following statements about elements in group VII is correct?
A. Br2 will oxidiza Cl–
B. F2 has the least tendency to be reduced
C. Cl2 will oxidize I–
D. I2 is a stronger oxidizing agent than F2
48.
Electrovalent compounds normally
A. have low boiling points
B. have high mobile electrons
C. conduct electricity in solid state
D. dissolve in polar solvents
49.
A coordinate covalent bond could be formed between
A. NH3 and PCl3
B. BCl3 and AlCl3
C. BCl3 and NH3
D. H+ and AlCl3
50.
Which of the following scientists discovered the electron?
A. Joseph J. Thompson
B. James Chadwick
C. Amedeo Avogadro
D. Ernest Rutherford