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?
Trả lời
(C)
3
2
Which of the following can be obtained by fractional distillation?
Trả lời
(A)
Nitrogen from liquid air
3
Duralumin consists of aluminum, copper?
Trả lời
(D)
Manganese and Magnesium
4
An example of a polysaccharide is?
Trả lời
(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?
Trả lời
(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?
Trả lời
(A)
with cool running water
7
Which of the gas laws does this graph illustrate?
Trả lời
(B)
Charles
8
What are the possible oxidation numbers of an element if its atomic number is 17?
Trả lời
(A)
-1 and 7
9
What process would coal undergo to give coal gas, coal tar, ammoniacal liquor and coke?
Trả lời
(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 ?
Trả lời
(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?
Trả lời
(C)
Oxyacetylene flame
12
Which of the following substances is a mixture?
Trả lời
(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?
Trả lời
(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?
Trả lời
(B)
Q
15
The products of the thermal decomposition of ammonium trioxonitrate(v) are?
Trả lời
(A)
Nitrogen (I) Oxide and Water
16
How many valence electrons are contained in the element \(^{31}_{15}P\)?
Trả lời
(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?
Trả lời
(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\(^{3}\) ]
Trả lời
(D)
71
19
Which of the following gases will rekindle a brightly splint?
Trả lời
(C)
N\(_2\)O
20
The shape of ammonia molecule is?
Trả lời
(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?
Trả lời
(A)
less than 3.4
22
Chromatography is used to separate components of mixture which differ in their rates of ?
Trả lời
(B)
migration
23
Deliquescent substances are also?
Trả lời
(C)
hygroscopic
24
Helium is used in observation of ballons because it is?
Trả lời
(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?
Trả lời
(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]
Trả lời
(C)
MCl\(_3\)
27
What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
Trả lời
(B)
48,250 C
28
Which of the following types of bonding does not involve the formation of new substances?
Trả lời
(A)
Metallic
29
An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?
Trả lời
(A)
Alkene
30
The substance often used for vulcanization of rubber is?
Trả lời
(C)
Sulphur
31
The chlorinated alkane often used industrially to remove grease is?
Trả lời
(A)
Tetrachloromethane
32
What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?
Trả lời
(D)
72.0g
33
Proteins in acid solution undergo?
Trả lời
(C)
Hydrolysis
34
The general formula for the Alkanals is?
Trả lời
(B)
RCHO
35
When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes?
Trả lời
(B)
Negatively charged