2019 - JAMB Chemistry Past Questions and Answers - page 4
31
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\(^{-1}\))
A
2.0 moldm\(^{-3}\)
B
0.25 moldm\(^{-3}\)
C
1.0 moldm\(^{-3}\)
D
0.5 moldm\(^{-3}\)
32
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
A
ii and iii only
B
ii and iv only
C
iii and iv only
D
i and ii only
33
The molecular shape and bond angle of water are respectively
A
linear, 180°
B
bent, 109.5°
C
tetrahedral, 109.5°
D
bent, 105°
34
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
A
5
B
7
C
3
D
9
35
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
A
75,000 particles
B
35,000 particles
C
25,000 particles
D
50,000 particles
36
Which two gases can be used for the demonstration of the fountain experiment?
A
SO\(_3\) and NH\(_3\)
B
SO\(_2\) and NH\(_3\)
C
HCl and NH\(_3\)
D
SO\(_2\) and HCl
37
Which of the following pollutants will lead to the depletion of ozone layer?
A
chlorofluorocarbon
B
carbon (ii) oxide
C
hydrogen sulphide
D
sulphur (iv) oxide
38
Which of the following describes the chemical property of acids?
A
None of the above
B
Acid + XCO\(_3\) \(\to\) Salt + H\(_2\)O + NH\(_3\)
C
Acid + NaOH \(\to\) Normal salt + CO\(_2\)
D
Acid + X\(_n\)CO\(_3\) \(\to\) Salt + H\(_2\)O + CO\(_2\)
39
Which of the following pairs cannot be represented with a chemical formula?
A
air and bronze
B
bronze and sodium chloride
C
copper and sodium chloride
D
caustic soda and washing soda
40
Consider the equation below:
Cr\(_2\)O\(_7 ^{2-}\) + 6Fe\(^{2+}\) + 14H\(^{+}\) \(\to\) 2Cr\(^{3+}\) + 6Fe\(^{3+}\) + 7H\(_2\)O.
The oxidation number of chromium changes from
A
+5 to +3
B
+6 to +3
C
-2 to +3
D
+7 to +3
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