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Chemistry
UTME / JAMB 2018
Atomic Structure and Periodic Table
The number of electrons in the valence shell of an element of atomic number 14 is?
A
1
B
2
C
3
D
4
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #47329)
Chemistry
UTME / JAMB 2018
Stoichiometry & Mole Concept
Solution
What volume of oxygen will remain after reacting 8cm\(^3\) of hydrogen gas with 20cm\(^3\) of oxygen gas?
A
10cm\(^3\)
B
12cm\(^3\)
C
14cm\(^3\)
D
16cm\(^3\)
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
First we need to write the balanced chemical equation:
2H\(_2\) + O\(_2\) → 2H\(_2\)O
Reacting moles: 2 moles : 1 moles 2 moles
Expected reacting Volume: 8 cm\(^3\): 20 cm\(^3\)
Actual reacted Volume: 8 cm\(^3\): 4cm\(^3\) (Based on the balanced equation)
Residual Volume(Expected - Actual): 0cm\(^3\) : 16cm\(^3\)
Therefore, 16cm\(^3\) of Oxygen will remain after reacting 8cm\(^3\) of hydrogen gas with 20cm\(^3\) of oxygen gas.
Source: Myschool Past Questions Archive (Record #47330)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
Solution
If one of the following oxides is heated with hydrogen or carbon using a bunsen burner. it is not reduced to the metal, Which one is it?
A
lead oxide
B
Magnesium oxide
C
Copper oxide
D
Tin oxide
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
The oxides of Potassium, Sodium, Calcium, and Magnesium are not reduced when they react with carbon and hydrogen.
Source: Myschool Past Questions Archive (Record #47331)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
Diagram
Solution
The lUPAC name for
Attached Figure / Diagram
A
1-methyl pentane
B
3-methylbutane
C
2-methylbutane
D
1-dimethyl propane
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
The longest carbon chain is butane, with one substituent attached at carbon number 2
therefore the compound is named 2-methyl butane
Source: Myschool Past Questions Archive (Record #47332)
Chemistry
UTME / JAMB 2018
Kinetics, Energetics and Equilibrium
mE + nF -----> pG + qH
In the equation shown, the equilibrium constant is given by?
A
\(\frac{[E]^m[F]}{[G]^p[H]^q}\)
B
\(\frac{[E][F]}{[G][H]}\)
C
\(\frac{[G]^p[H]^q}{[E]^m[F]^n}\)
D
\(\frac{[G][H]}{[E][F]}\)
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #47339)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
(I). 3CuO(s) + 2NH3(g) -----> 3Cu(s) + 3H2O(l) + N2(g)
(II). 2NH3(g) + 3Cl2(g) -----> 6HCl(g) + N2(g)
(III). 4NH3(g) + 3O2(g) -----> 6H2O(l) + N2(g)
The reactions represented by the equations above demonstrate the
A
basic properties of ammonia
B
acidic properties of ammonia
C
reducing properties of ammonia
D
oxidizing properties of ammonia
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #47340)
Chemistry
UTME / JAMB 2018
Acids, Bases, and Salts
Solution
The salt that reacts with dilute hydrochloric acid to produce a pungent smelling gas which decolourizes acidified purple potassium tetraoxomanganate (VII) solution is
A
Na\(_2\)SO\(_4\)
B
Na\(_2\)SO\(_3\)
C
Na\(_2\)S
D
Na\(_2\)CO\(_3\)
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
When sodium sulphite (Na₂SO₃) reacts with hydrochloric acid (HCl), it produces sulphur dioxide gas (SO₂), which readily decolourises acidified potassium permanganate (KMnO₄) solution.
Reaction: Na₂SO₃(aq) + 2HCl(aq) → 2NaCl(aq) + H₂O(l) + SO₂(g)
The reaction produces sodium chloride (NaCl), water (H₂O), and sulphur dioxide gas (SO₂). Sulphur dioxide gas (SO₂) is a reducing agent, and when it reacts with acidified potassium permanganate (KMnO₄), it decolourises the purple solution.
Source: Myschool Past Questions Archive (Record #47341)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
The refreshing and characteristic taste of soda water and other soft drinks is as a result of the presence of
A
carbon(IV)oxide
B
carbon(ll)oxide
C
soda
D
glucose
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #47342)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
Which of the following are mixtures?
I. Petroleum
II. Rubber latex
III. Vulcanizer's solution
IV. Carbon sulphide
A
I, II and III
B
I, II and IV
C
I and II only
D
I and IV
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #47343)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
A balanced chemical equation obeys the law of
A
conservation of mass
B
definite proportions
C
multiple proportions
D
conservation of energy
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #47344)
Chemistry
UTME / JAMB 2018
Atomic Structure and Periodic Table
Solution
When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;
A
nitrogen and carbondioxide
B
the rare gases
C
nitrogen and oxygen
D
nitrogen and the rare gases
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The quick-lime is a drying agent that can dry most gases except ammonia. Hence it removes the water vapour. Quick-lime which is calcium oxide reacts with the carbon dioxide forming calcium carbonate. Hence carbon dioxide and monoxide is eliminated leaving nitrogen, and the rare gases
Source: Myschool Past Questions Archive (Record #47628)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
Solution
In the laboratory preparation of oxygen, the gas cannot be collected by downward displacement of air because
A
the density of oxygen is greater than that of air
B
the density of air is nearly the same as that of oxygen
C
oxygen is a component of air
D
air is an impure substance
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Oxygen is collected in downward displacement of water because:-
Oxygen is only slightly soluble in water. Therefore, it can be collected over water without the fear of excessive dilution.
Oxygen is slightly heavier than air, so it cannot be collected over air.
Source: Myschool Past Questions Archive (Record #47629)
Chemistry
UTME / JAMB 2018
Kinetics, Energetics and Equilibrium
Solution
2KClO\(_3\)(s) → 2KCl(s) + 3O\(_2\)(g)
The importance of the catalyst in the reaction above is that
A
heating may not be required before the reaction takes place
B
the reaction is controllable even at a high temperature
C
the reaction produces large quantity of oxygen
D
the reaction takes place more rapidly at a lower temperature
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
A catalyst is a substance that enables a chemical reaction to proceed at a usually faster rate or under different conditions (as at a lower temperature) than otherwise possible.
Source: Myschool Past Questions Archive (Record #47630)
Chemistry
UTME / JAMB 2018
Atomic Structure and Periodic Table
Solution
Which of the following is used to power steam engines?
A
lubricating oil
B
coal
C
bitumen
D
diesel oil
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
When we burn coal on a fire, the bonds break apart and the energy is released in the form of heat. Coal contains about half as much energy per kilogram as cleaner fossil fuels such as gasoline, diesel, and kerosene—and that's one reason why steam engines have to burn so much of it.
Coal is the fuel used to power steam engines.
Source: Myschool Past Questions Archive (Record #47631)
Chemistry
UTME / JAMB 2018
Stoichiometry & Mole Concept
Solution
In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?
A
5cm\(^3\)
B
10cm\(^3\)
C
20cm\(^3\)
D
50cm\(^3\)
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
2NaOH + H\(_2\) SO\(_4\)↔Na\(_2\)SO\(_4\) + 2H\(_2\)O
V x 0.5M = 2(10 x 1.25)
0.5V = 2 x 12.5
0.5V = 25
V = 250.5 = 50cm\(^2\)
Correct computation as it follows the equation specified.
Source: Myschool Past Questions Archive (Record #47633)