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Chemistry
UTME / JAMB 2020
Stoichiometry & Mole Concept
Solution
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\(^{3}\) ]
A
28
B
32
C
44
D
71
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
500cm\(^3\) of the gas weighed 1.58
: 22400cm\(^3\) of the gas weight
[22400 X 1.58g] \div [ 500 ]
= 71
Source: Myschool Past Questions Archive (Record #56771)
Chemistry
UTME / JAMB 2020
Matter & Separation Techniques
Solution
Which of the following gases will rekindle a brightly splint?
B
NO\(_2\)
C
N\(_2\)O
D
CL\(_2\)
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Nitrogen(I)Oxide rekindles a brightly glowing splinter but extinguishes a feebly glowing one which is not hot enough to decompose the gas to liberate oxygen
Source: Myschool Past Questions Archive (Record #56772)
Chemistry
UTME / JAMB 2020
Atomic Structure and Periodic Table
Solution
The shape of ammonia molecule is?
A
Trigonal planar
B
Octahedral
C
Square planar
D
Tetrahedral
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The ammonia molecule has a trigonal pyramidal shape with the three hydrogen atoms and an unshared pair of electrons attached to the nitrogen atom.
Source: Myschool Past Questions Archive (Record #56774)
Chemistry
UTME / JAMB 2020
Matter & Separation Techniques
Solution
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?
A
less than 3.4
B
greater than 3.4
C
unaltered
D
the same as that of the pure water
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The addition of conc HCL makes the solution more acidic and the solution falls below the original value
Source: Myschool Past Questions Archive (Record #56781)
Chemistry
UTME / JAMB 2020
Matter & Separation Techniques
Solution
Chromatography is used to separate components of mixture which differ in their rates of ?
A
diffusion
B
migration
C
reaction
D
sedimentation
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Chromatography is a method of separating mixtures by using a moving solvent on filter paper.
The rate at which each solute moves up the paper depends on how strongly it is absorbed by the paper, and how soluble it is in the solvent.
Source: Myschool Past Questions Archive (Record #56784)
Chemistry
UTME / JAMB 2020
Acids, Bases, and Salts
Solution
Deliquescent substances are also?
A
efflorescent
B
anhydrous
C
hygroscopic
D
insoluble
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Deliquescence, the process by which a substance absorbs moisture from the atmosphere until it dissolves in the absorbed water and forms a solution. Deliquescence occurs when the vapour pressure of the solution that is formed is less than the partial pressure of water vapour in the air. A particular example of hygroscopic behavior is deliquescence which is exhibited by many water-soluble solids, including inorganic salts (e.g., calcium chloride).
Source: Myschool Past Questions Archive (Record #56787)
Chemistry
UTME / JAMB 2020
Stoichiometry & Mole Concept
Solution
Helium is used in observation of ballons because it is?
A
Light and combustible
B
light and non-combustible
C
heavy and combustible
D
heavy and non-combustible
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Helium floats because it is buoyant; its molecules are lighter than the nitrogen and oxygen molecules of our atmosphere and so they rise above it
Source: Myschool Past Questions Archive (Record #56791)
Chemistry
UTME / JAMB 2020
Stoichiometry & Mole Concept
Solution
32g of anhydrous copper(ii)tetraoxosulphate(vi) dissolved in 1dm\(^3\) of water generated 13.0kj of heat. The heat solution is?
A
26.0kj/mol
B
65.0kj/mol
C
130.0kj/mol
D
260.0kj/mol
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
32g of CUSO\(_4\) liberate 13.0kj of heat
Molar mass of CUSO\(_4\) = 160g
No. of moles of CUSO\(_4\) = 32g
No. of moles = 32(mass) / 160(molar mass)
= 0.2 moles
i.e 0.2 = 13kj
1 moles = xkj
: 65KJ
Source: Myschool Past Questions Archive (Record #56798)
Chemistry
UTME / JAMB 2020
Stoichiometry & Mole Concept
Solution
A gaseous metallic chloride MCl consists of 20.22% of M by mass. The formula of the chloride is?
[ M = 27, Cl = 35.5]
A
MCl
B
MCl\(_2\)
C
MCl\(_3\)
D
M\(_2\)Cl\(_6\)
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
M
Cl
% composition
20.22
79.78
Atomic mass
27
35.5
Mole ratio
20.22
79.78
27
35.5
0.75
2.25
Divided
0.75
0.75
1
3
The formula of the Chloride = MCl\(_3\)
Source: Myschool Past Questions Archive (Record #56803)
Chemistry
UTME / JAMB 2020
Stoichiometry & Mole Concept
Solution
What quantity of electricity will liberate 0.125 mole of oxygen molecules during the electrolysis of dilute sodium chloride solution?
A
24,125 C
B
48,250 C
C
72,375 C
D
96,500 C
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
4OH ⇒ 2H\(_2\)O + O\(_2\) + 4e-
From the equation:
1 mole of Oxygen requires 4e
i.e 1 mole of Oxygen requires 4F,
where 1F = 96,500 C
[ 4 X 96,500 X 0.125 ] \div 1
= 48,250 C
Source: Myschool Past Questions Archive (Record #56811)
Chemistry
UTME / JAMB 2020
Atomic Structure and Periodic Table
Solution
Which of the following types of bonding does not involve the formation of new substances?
A
Metallic
B
Covalent
C
Co-ordinate
D
Electrovalent
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
metallic bond does not involve the formation of a new substance. It is responsible for several characteristic properties of metals such as their shiny lustre, their malleability, and their conductivities for heat and electricity
Source: Myschool Past Questions Archive (Record #56812)
Chemistry
UTME / JAMB 2020
Matter & Separation Techniques
Solution
An organic compound that does not undergo a reaction with both hydrogen cyanide and hydroxylamine can be?
A
Alkene
B
Alkanal
C
Alkanone
D
Alkanoic Acid
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
alkanone & alkanal react with HCN to form compounds known as cyanohyderins. They also react with hydroxylamine to form oximes.
Source: Myschool Past Questions Archive (Record #56813)
Chemistry
UTME / JAMB 2020
Matter & Separation Techniques
Solution
The substance often used for vulcanization of rubber is?
A
Chlorine
B
Hydrogen peroxide
C
Sulphur
D
Tetraoxosulphate(vi) acid
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
One of the several uses of sulfur is for the vulcanization of rubber.
Source: Myschool Past Questions Archive (Record #56814)
Chemistry
UTME / JAMB 2020
Organic Chemistry
Solution
The chlorinated alkane often used industrially to remove grease is?
A
Tetrachloromethane
B
Chloromethane
C
Trichloromethane
D
Dichloromethane
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Tetrachloromethane ( carbon tetrachloride) is an effective solvent within the chemical industry and is used to clean machinery and electrical equipment.
I.e as a solvent for oils, fats, lacquers, varnishes, rubber waxes, and resins, and as a grain fumigant.
Source: Myschool Past Questions Archive (Record #56815)
Chemistry
UTME / JAMB 2020
Stoichiometry & Mole Concept
Solution
What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen?
A
8.0g
B
16.0g
C
36.0g
D
72.0g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
2H\(_2\) + O\(_2\) ⇒ 2H\(_2\)O
From the equation:
4g of Hydrogen produces 36g of water
: 8g of Hydrogen will produce 72g of water
Source: Myschool Past Questions Archive (Record #56816)