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Chemistry
UTME / JAMB 2022
Water, Solutions & Solubility
Solution
Addition of charcoal to the filter bed of sand during water treatment for township supply is to?
A
prevent goiter
B
prevent tooth decay
C
remove odour
D
kill germs
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Activated Carbon filters are excellent at removing chlorine and related poor taste and odor.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64922)
Chemistry
UTME / JAMB 2022
Water, Solutions & Solubility
Solution
What volume of (dm\(^3\)) of water will be added to 10dm\(^3\) of 2.0 mol/dm\(^3\) HCL acid solution to give a final solution of 0.5 mol/dm\(^3\)?
A
30
B
40
C
20
D
50
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
To make a fixed amount of a dilute solution from a stock solution,
use the formula: C\(_1\)V\(_1\) = C\(_2\)V\(_2\)
where: V\(_1\) = Volume of stock solution needed to make the new solution.
C\(_1\) = Concentration of stock solution.
V\(_2\) = Final volume of new solution.
C\(_2\)= Final concentration of stock solution
2 * 10 = 0.5 * V2
20 = 0.5V2
\(\frac{20}{0.5}\) = V2
V\(_2\)= 40dm\(^3\)
What would be added = V\(_2\) - V\(_1\)
= 40 - 10 = 30dm\(^3\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #65039)
Chemistry
UTME / JAMB 2022
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
2H\(_2\) + O\(_2\) → 2H\(_2\)O
From the equation above, calculate the volume of unreacted oxygen gas if a mixture of 50cm\(^3\) of hydroden and 75cm\(^3\) of oxygen are involved
A
85cm\(^3\)
B
50cm\(^3\)
C
125cm\(^3\)
D
55cm\(^3\)
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Since 2 mol H\(_2\) reacted with 1 mol of O\(_2\)
: 50cm\(^3\) of hydrogen reacted with 25cm\(^3\) of oxygen
Remainder oxygen = Supplied amount - Reacted amount → 75cm\(^3\) - 25cm\(^3\)
= 50cm\(^3\)
Source: WAEC / JAMB / NECO Classroom Archive (Record #64961)
Chemistry
UTME / JAMB 2022
Electrolysis & Electrochemical Cells
Solution
On the basis of the electrochemical series, which of these ions will show the greater tendency to be discharged at the cathode in an electrolytic cell
A
cu\(^{2+}\)
B
sn\(^{2+}\)
C
fe\(^{2+}\)
D
zn\(^{2+}\)
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The arrangement of elements in order of increasing electrode potential values is called electrochemical series.
K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Ag > Au.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64917)
Chemistry
UTME / JAMB 2022
Electrolysis & Electrochemical Cells
Solution
In order to electroplate spoon with silver, the arrangement of the electrolytic cell is?
A
the anode is a silver rod and the cathode is the spoon
B
the anode is the spoon and the cathode is a silver rod
C
the electrolyte is silver trioxonitrate(v)( solution and the cathode is a silver rod.
D
the electrolyte is silver trioxonitrate(v) solution and the anode is the spoon
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The steel spoon to be coated with silver is the cathode of the electrolytic cell and the anode of the electrolytic cell is made of a silver metal
Source: WAEC / JAMB / NECO Classroom Archive (Record #64950)
Chemistry
UTME / JAMB 2022
Reaction Rates & Chemical Equilibrium
Solution
N\(_2\)O\(_4\) ⇔ 2NO\(_2\) (Δ = -ve)
From the reaction above, which of these conditions would produce the highest equilibrium yield for N\(_2\)O\(_4\)?
A
Low temperature and high pressure
B
Low temperature and low pressure
C
high temperature and low pressure
D
high temperature and high pressure
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
high temperature and high pressure favor the highest yield for N\(_2\)O\(_4\)
high temperature favours the production of the reactant since it is endothermic, while high pressure favours the side involving a decrease in volume.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64936)
Chemistry
UTME / JAMB 2022
Reaction Rates & Chemical Equilibrium
Solution
The reactions below represent neutralization reaction, in which of them is the value of ΔH highest?
A
CH\(_3\)CH\(_2\)COOH + KOH → CH\(_3\)CH\(_2\)COOK + H\(_2\)O
B
NH\(_4\)OH + HCL → NH\(_4\) + H\(_2\)O
C
NaOH + HCL → NaCL + H\(_2\)O
D
CH\(_3\)COOH + NaOH → CH\(_3\)COONa + H\(_2\)O
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
The enthalpy change of neutralisation involving weak acids are smaller in magnitude compared to that between strong acids and strong bases. This is because weak acids/bases are partially dissociated, which means not all hydrogen ions are free to react with hydroxide ions.
For strong acids and bases, the enthalpy of neutralisation values are always closely similar with the values -57 and -58 KJ/mol. We know that strong acids completely ionize in water. In case of weak acids, only partial dissociation of its ions occurs.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64973)
Chemistry
UTME / JAMB 2022
Reaction Rates & Chemical Equilibrium
Solution
When heat is absorbed during a chemical reaction, the reaction is said to be
A
thermodynamic
B
exothermic
C
isothermal
D
endothermic
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
An endothermic reaction is any chemical reaction that absorbs heat from its environment.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64988)
Chemistry
UTME / JAMB 2022
Non-Metals & Their Compounds
Solution
In which of the following will hydrogen form ionic compound?
A
HCL
B
NaH
C
NH\(_3\)
D
CH\(_4\)
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
NaH is a saline (salt-like) hydride, composed of Na+ and H− ions.
NaH (sodium hydride) is considered an ionic compound because it is composed of a metal (sodium) and a non-metal (hydrogen), where sodium readily loses an electron to form a positive ion (Na+) and hydrogen gains an electron to form a negative ion (H-) creating an ionic bond between them.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64962)
Chemistry
UTME / JAMB 2022
Non-Metals & Their Compounds
Solution
The following non-metal form acidic oxides with oxygen except?
A
phosphorus
B
sulphur
C
carbon
D
chlorine
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
The oxides which neither react with acids nor react with bases are known as neutral oxides.
Carbon monoxide neither reacts with acids nor reacts with bases.
Thus, carbon monoxide is a neutral oxide, produced when combustion reactions are not fully completed, either through lack of oxygen or due to low mixing
Source: WAEC / JAMB / NECO Classroom Archive (Record #64904)
Chemistry
UTME / JAMB 2022
Non-Metals & Their Compounds
Solution
A colored gas that is known to be poisonous and can readily damage the mucous lining of the lungs is?
A
hydrogen sulphide
B
carbon(ii)oxide
C
chlorine
D
sulphur(iv)oxide
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Chlorine is a yellow-green gas at room temperature. Chlorine has a pungent, irritating odor similar to bleach that is detectable at low concentrations.
Exposure to low concentrations of chlorine (1 to 10 ppm) may cause eye and nasal irritation, sore throat, and coughing. Inhalation of higher concentrations of chlorine gas (>15 ppm) can rapidly lead to respiratory distress with airway constriction and accumulation of fluid in the lungs (pulmonary edema).
Source: WAEC / JAMB / NECO Classroom Archive (Record #64944)
Chemistry
UTME / JAMB 2022
Non-Metals & Their Compounds
Solution
The pollutant usually presents in a city which generates its electricity from coal?
A
fog
B
carbon(ii)oxide
C
smog
D
sulphur(iv)oxide
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
In the majority of power plants, sulfur appears due to coal burning which is used to generate electricity.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64978)
Chemistry
UTME / JAMB 2022
Non-Metals & Their Compounds
Solution
How many bonding pair are present in carbon(iv)oxide?
A
4
B
3
C
2
D
1
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
There are 4 bond pairs in COâ‚‚ and no lone pairs are there.
Source: WAEC / JAMB / NECO Classroom Archive (Record #65005)
Chemistry
UTME / JAMB 2022
Non-Metals & Their Compounds
Solution
SO\(_2\) + O\(_2\) → 2SO\(_3\)
In the reaction above, the most suitable catalyst is?
A
chromium(vi)oxide
B
iron(iii)oxide
C
copper(i)oxide
D
vanadium(v)oxide
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
During the Contact Process for manufacturing sulfuric acid, sulfur dioxide has to be converted into sulfur trioxide, which is done by passing sulfur dioxide and oxygen over a solid vanadium(V) oxide catalyst.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64902)
Chemistry
UTME / JAMB 2022
Non-Metals & Their Compounds
Solution
The sulphide that is commonly used in coating electric fluorescent tubes is?
A
iron(ii)Sulphide
B
tin(ii)sulphide
C
Zinc Sulphide
D
lead(iv) Sulphide
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
ZnS (Zinc Sulfide) screen was used because it emits a flash of light when struck by an alpha particle.
This is a phenomenon called Radio luminescence in which a flash of light is observed on the screen when acted upon by a radioactive substance.
Source: WAEC / JAMB / NECO Classroom Archive (Record #64907)