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Chemistry
UTME / JAMB 2009
Reaction Rates & Chemical Equilibrium
Diagram
Solution
In the diagram above, which of the curves represents the evolution of oxygen with time in the equation 2KClO3(s) → 2KCl(s) + 3O2(g)?
Attached Figure / Diagram
A
X
B
Y
C
Z
D
R
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The curve that represents the evolution of oxygen over time for the reaction 2KClO\(_3\)(s) → 2KCl(s)+3O\(_2\)\(_g\) would start at a concentration of zero and then increase, with the rate of increase slowing down over time until it reaches a constant, maximum value.
At the beginning of the reaction (t=0), no oxygen has been produced. As the reaction proceeds, the amount of oxygen gas increases. The reaction rate is fastest at the start when the concentration of the reactant,KClO\(_3\), is highest. As the reactant is consumed, the rate of the reaction slows down, which is reflected in the curve's slope becoming less steep. Once all of the KClO\(_3\) has reacted, the amount of oxygen produced will no longer increase, and the curve will flatten out.
Source: Myschool Past Questions Archive (Record #4323)
Chemistry
UTME / JAMB 2009
Non-Metals & Their Compounds
Solution
The gasification of coke is used for the manufacturing of?
A
producer gas
B
natural gas
C
synthetic gas
D
industrial gas
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Producer gas is manufactured by the partial combustion or gasification of coke (or coal) in a furnace where a limited supply of air and steam is passed through a red-hot bed of coke. This process yields a gaseous fuel consisting primarily of carbon monoxide (CO), hydrogen (H\(_2\)), and a high concentration of nitrogen (N\(_2\)) from the injected air.
Source: Myschool Past Questions Archive (Record #4329)
Chemistry
UTME / JAMB 2009
Metals, Transition Elements & Extraction
In the electrolytic extraction of aluminum, the function of the molten cryolite is to
A
precipitate aluminium hdroxide
B
lower the melting point of aluminium oxide
C
act as a raw materials
D
act as a solvent
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #4345)
Chemistry
UTME / JAMB 2009
Organic Chemistry I: Hydrocarbons & Crude Oil
A cracking process in petroleum refining can be represented by
A
heptane to heptene
B
heptane to 3-methylhexane
C
heptane to propene and butane
D
heptane to 2,3,3-trimethybutane
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 #4347)
Chemistry
UTME / JAMB 2009
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Which of the following class of compounds can exist as dipolar ions in solution?
A
Alkanoic acid
B
Fatty acids
C
Dialkanoic acids
D
Amino acids
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 #4349)
Chemistry
UTME / JAMB 2009
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Solution
Lucas reagent is used to test for?
A
alkanes
B
alkanoic acids
C
alkanols
D
amines
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Lucas' reagent is a solution of anhydrous zinc chloride in concentrated hydrochloric acid. This solution is used to classify alcohols.
Source: Myschool Past Questions Archive (Record #4456)
Chemistry
UTME / JAMB 2009
Organic Chemistry I: Hydrocarbons & Crude Oil
A compound commonly used for sterilization and preservation of specimens and food is
A
ethanol
B
benzene
C
ether
D
ammonia
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 #4457)
Chemistry
UTME / JAMB 2009
Organic Chemistry I: Hydrocarbons & Crude Oil
Which of the following hydrocarbons is mainly used as fuel?
A
Methylene
B
Ethylene
C
Methane
D
Ethyne
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 #4459)
Chemistry
UTME / JAMB 2009
Stoichiometry, Mole Concept & Volumetric Analysis
The molecular formula of a common organic laboratory anaesthetic is
A
CHCl3
B
CHI3
C
CCl4
D
CHF3
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 #4460)
Chemistry
UTME / JAMB 2009
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
The simplest branched-chain hydrocarbon is
A
ethane
B
ethene
C
propane
D
butane
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The smallest branched alkane is isobutane. Notice that isobutane has the same molecular formula, C4H10, as n-butane but has a different structural formula.
Source: Myschool Past Questions Archive (Record #4461)
Chemistry
UTME / JAMB 2009
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
If the relative atomic mass of an element is not a whole number, it can be deduced that the element is?
A
Naturally radioactive
B
abundant in nature
C
a transition metal
D
an isotopic mixture
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
This happens because the relative atomic mass is the average of all an element’s isotopes, weighted by how common each isotope is. If the isotopes have different masses, the average won’t be a whole number.
Source: Official Exam / Past Question Archive
Chemistry
WAEC / WASSCE 2009
Atomic Structure, Orbitals & Nuclear Chemistry
Which of the following scientists discovered the neutron?
A
Ernest Rutherford
B
J.J Thompson
C
James Chadwick
D
R. A. M illikan
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 #37308)
Chemistry
WAEC / WASSCE 2009
Atomic Structure, Orbitals & Nuclear Chemistry
How many protons does 4020Ca contain?
A
20
B
30
C
40
D
60
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 #37309)
Chemistry
WAEC / WASSCE 2009
Particulate Nature of Matter, Laws & Formulae
If 100 atoms of element X contains 70 atoms of 9X and 30 atoms of 11X, calculate the relative atomic mass of X
A
9.6
B
10.6
C
11.6
D
20.0
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 #37313)
Chemistry
WAEC / WASSCE 2009
Atomic Structure, Orbitals & Nuclear Chemistry
Consider the reaction represented by the equation: 23892U + 10 → 139 56Ba + 94 36Kr + 31 0n. The reaction represents a
A
nuclear fission
B
nuclear fusion
C
radioactive decay
D
spontaneous disintegration
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 #37317)