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JAMB - Chemistry (2020)

1
The electronic configuration of an element is 1S\(^2\) 2S\(^2\) 2P\(^6\) 3S\(^2\) 3P\(^3\). How many unpaired electrons are there in the element?
Answer
(C)
3
2
Which of the following can be obtained by fractional distillation? 
Answer
(A)
Nitrogen from liquid air
3
Duralumin consists of aluminum, copper?
Answer
(D)
Manganese and Magnesium
4
An example of a polysaccharide is?
Answer
(D)
Starch
5
8g of CH\(_4\) occupies 11.2 at S.T.P. What volume would 22g of CH\(_3\)CH\(_2\)CH\(_3\) occupy under the same condition?
Answer
(B)
11.2dm\(^3\)
6
The best treatment for a student who accidentally poured conc tetraoxosulphate(vi) on his skin in the laboratory is to wash his skin with?
Answer
(A)
with cool running water
7

Which of the gas laws does this graph illustrate?

Answer
(B)
Charles
8
What are the possible oxidation numbers of an element if its atomic number is 17?
Answer
(A)
-1 and 7
9
What process would coal undergo to give coal gas, coal tar, ammoniacal liquor and coke?
Answer
(B)
Destructive distillation
10
Liquid black soap is made by boiling palm oil with liquid extract of ash. The function of the ash is to provide the ?
Answer
(C)
Alkali
11
When water drops are added to calcium carbide in a container and the gas produced is passed through a jet and lighted, the resultant flame is called an?
Answer
(C)
Oxyacetylene flame
12
Which of the following substances is a mixture?
Answer
(B)
Seawater
13
If the quantity of oxygen occupying 2.76L container at a pressure of 0.825 atm and 300k is reduced by one-half, what is the pressure exerted by the remaining gas?
Answer
(A)
1.650atm
14
Four elements P, Q, R and S have atomic numbers of 4, 10, 12 and 14 respectively. Which of these elements is noble gas? 
Answer
(B)
Q
15
The products of the thermal decomposition of ammonium trioxonitrate(v) are?
Answer
(A)
Nitrogen (I) Oxide and Water
16
How many valence electrons are contained in the element \(^{31}_{15}P\)?
Answer
(A)
3
17

The number of molecules of Carbon(iv)Oxide produced when 10.0g of CaCO\(_3\) is treated with 0.2dm\(^3\) of 1 Mole of HCL in the equation

CaCO\(_3\) + 2HCL ⇒ CaCl\(_2\)  + H\(_2\) O + CO\(_2\)  , is?

Answer
(C)
6.02 X 10\(^{22}\)
18
The volume occupied by 1.58g of a gas at S.T.P is 500cm\(^3\). What is the relative molecular mass of the gas?  [ G.M.V at S.T.P = 22.4dm\(^{3}\) ]
Answer
(D)
71
19
Which of the following gases will rekindle a brightly splint?
Answer
(C)
N\(_2\)O
20
The shape of ammonia molecule is?
Answer
(A)
Trigonal planar
21
A few drop of conc HCL are added to about 10cm\(^3\) of a solution of PH 3.4. The PH of the resulting mixture is?
Answer
(A)
less than 3.4
22
Chromatography is used to separate components of mixture which differ in their rates of ?
Answer
(B)
migration
23
Deliquescent substances are also?
Answer
(C)
hygroscopic
24
Helium is used in observation of ballons because it is?
Answer
(B)
light and non-combustible
25
32g of anhydrous copper(ii)tetraoxosulphate(vi) dissolved in 1dm\(^3\) of water generated 13.0kj of heat. The heat solution is?
Answer
(B)
65.0kj/mol
26

A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?

[ M = 27, Cl = 35.5]

Answer
(C)
MCl\(_3\)
27
What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
Answer
(B)
48,250 C
28
Which of the following types of bonding does not involve the formation of new substances?
Answer
(A)
Metallic
29
An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?
Answer
(A)
Alkene
30
The substance often used for vulcanization of rubber is?
Answer
(C)
Sulphur
31
The chlorinated alkane often used industrially to remove grease is?
Answer
(A)
Tetrachloromethane
32
What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?
Answer
(D)
72.0g
33
Proteins in acid solution undergo?
Answer
(C)
Hydrolysis
34
The general formula for the Alkanals is?
Answer
(B)
RCHO
35
When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes?
Answer
(B)
Negatively charged