2015 - JAMB Chemistry Past Questions and Answers - page 5
41
When sugar is dissolve in ten, the reaction is accomplished by
A
positive change
B
negative entropy change
C
no entropy change
D
a minimum entropy change
correct option: c
No entropy change because the sugar will not change the chemical equivalent of the tea. Options A,B,D are not appropriate because they will change the chemical combination of the tea
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NH3(g) + HCl(s) → NH 4Cl (s)
The entropy change in the system above is
The entropy change in the system above is
A
positive
B
zero
C
negative
D
intermediate
correct option: c
Entropy s is a measure of the degree of disorder or randomness of a substance. The entropy charge in the system is negative. Options B, C, D will not give negative but the result into positive
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Detergents are manufacture with strength hydrocarbon chains is to make them
A
soluble
B
biodegradable
C
cheaper
D
foamy
correct option: b
Biodegradable because the straight hydrocarbons are natural and slightly soluble in water. Options A,C,D do not have strength hydrocarbon chains and they could harm the environment if they are made with the detergent
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Which of the following results in the fall of acid rain
A
oxide of lead
B
particulate matter
C
oxides of carbon
D
gaseous hydrocarbon
correct option: c
Oxide of sulphur is formed as a result of acid rain. Options A,B, D are not formed as a result of the pressure of acid
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The fuming of kettles is caused by the presence in the water of
A
calcium tetraoxosulphate (IV)
B
calcium hydrogentrionocarbonate (IV)
C
calcium hydroxide
D
calcium trioxocarbonate (IV)
correct option: b
Calcium hydrogen trionocarbonate (iv) will cause the forming of kettles whenever water is present. Options A, C, D will not react under the presence of water
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A difference between chemical and physical change is that in a chemical change
A
oxygen is consumed
B
heat is supplied
C
the reversible process occurs
D
a new substance is formed
correct option: d
In chemical change a new substance is formed while in physical change no new substance is formed. Options A,B,C are all properties of a physical change
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According to the kinetic theory an absence in temperature causes the kinetic energy of particles to
A
decrease
B
increase
C
remain constant
D
be zero
correct option: d
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PCL5(g)= PCL3(g) + Cl2(g)
In the reaction above, a decrease in pressure will
In the reaction above, a decrease in pressure will
A
Decelerate the reaction
B
Increase yield of Pcl3
C
Increase the yield of Pcl5
D
Accurate the reaction
correct option: b
If we decrease the pressure in the reaction, there will be rapid breakage spilling of pcl5. And these follows a principle that molecule of gases tends to move from a region of higher pressure to low pressure. Option A,C,D will not be affected by pressure decrease
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Which of the following gives a precipitation when treated with NaOH Solution?
A
AlCl3
B
NH4Cl
C
Na2CO3
D
CH3COONa
correct option: a
AlCl3 will give a precipitate when treated with solution. Option B,C,D will not give a precipitate when treated with NaOH solution
Users' Answers & Comments50
Electronic configuration of an elements 13x in the subsidiary energy level is
A
\( 1s^2 2s^2 2p^6 3s^2 3p^1 \)
B
\( 1s^22s^2 2p^4 3p^1 3s^1 \)
C
\( 1s^2 2s^2 2p^6 3s^2 3p^3 \)
D
\( 1s^1 2s^2 2p^6 3s^2 3p^4 \)
correct option: a
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