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Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
Solution
Which of the following methods can be used to obtain pure water from a mixture of sand, water and methanoic acid?
A
netralization with NaOHfoolowed by filtration
B
neutralization with NaOH followed by distillation
C
fractional distillation
D
filtration followed by distillation
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
To obtain pure water from a mixture of sand, water, and methanoic acid, we need to consider the properties of each component:
- Sand is insoluble in water and can be removed by filtration.
- Methanoic acid (formic acid) is a volatile liquid that can be separated from water by distillation.
- Water is the desired product.
Considering these properties, the correct answer is: Option D. (Filtration followed by distillation)
Here's the step-by-step process:
1. Filtration: Remove the sand from the mixture by passing it through a filter paper.
2. Distillation: Distill the resulting liquid mixture to separate the methanoic acid from the water. Since water has a lower boiling point than methanoic acid, it will vapourize and condense first, allowing you to collect the pure water.
Source: Myschool Past Questions Archive (Record #27464)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
How many atoms are present in 6.0g of magnesium?
[Mg = 24, NA = 6.02 x 1023 mol-1]
A
1.20 x 1022
B
2.41 x 1022
C
1.51 x 1023
D
3.02 x 1023
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 #27465)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
An increase in the pressure exerted on gas at a constant temperature results in
A
a decrease in the number of effective collisions
B
a decrease in volume
C
an increase in the average intermolecular distance
D
an increase in volume
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 #27467)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
2H2(g) + O2(g) → 2H2 O(g)
In the reaction above, what volume of hydrogen would be left over when 300 cm3 of oxygen and 1000 cm3 of hydrogen are exploded in a sealed tube?
A
200 cm3
B
400 cm3
C
600 cm3
D
700 cm3
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 #27468)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
l . Evaporation. ll. Sublimation. lll. Diffusion. IV. Brownian motion.
Which of the above can correctly be listed as evidences for the particulate nature of matter?
A
I and lll only
B
ll and lV only
C
l, ll and lll only
D
l, ll, lll and lV
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 #27469)
Chemistry
UTME / JAMB 2012
Atomic Structure and Periodic Table
If the elements X and Y have atomic numbers 11 and 17 respectively, what type of bond can they form?
A
Dative
B
Covalent
C
Ionic
D
Metallic
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 #27470)
Chemistry
UTME / JAMB 2012
Atomic Structure and Periodic Table
A hydrogen atom which has lost an electron contains
A
one proton only
B
one neutron only
C
one proton and one neutron
D
one proton, one electron and one neutron
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 #27471)
Chemistry
UTME / JAMB 2012
Atomic Structure and Periodic Table
The electronic configuration of Mg 2+ is
A
ls 22s 22P 63s23P2
B
Is22s22P6
C
ls22s22p63s2
D
ls22s22P4
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 #27472)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
Group VII elements are
A
monoatmic
B
good oxidizing agents
C
highly electropositive
D
electron donors
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 #27473)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
Which of the following is used to study the arrangement of particles in crystal lattices?
A
Alpha-particles
B
Beta-particles
C
Gamma-rays
D
X-rays
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 #27474)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
I. It has a varied composition from one place to another. ll. it constituents can be separated by physical means
lll. It contains unreactive noble gases
which of the above shows that air is a mixture?
A
I and ll only
B
ll and lll only
C
l and lll only
D
l,ll and lll
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 #27475)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
The chemicals used to soften hard water involves the addition of
A
insoluble sodium compounds which from soluble solutions of calcium and magesium
B
solube soudium compounds which from soluble solutions of calcium and magnesium ions
C
solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
D
insoluble precipitates of calcium and magnesium ions
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 #27476)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
Chlorination of water for town supply is carried out to
A
make the water colourless
B
remove germs from the water
C
make the water tastedful
D
remove odour from the water
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 #27477)
Chemistry
UTME / JAMB 2012
Matter & Separation Techniques
The solubilites of different solutes in a given solvent can be compared by
A
plotting their solubility curves on separete axes
B
plotting their solubility curves on the same axes
C
plotting some of the solubility curves on the x-axis and others on the y-axis
D
plotting their solubility curves on the x-axis only
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 #27478)
Chemistry
UTME / JAMB 2012
Stoichiometry & Mole Concept
Solution
Potassium trioxochlorate (V)has a solubility of 1.5 mol dm -3 at 45 oC.On cooling this solution to a temperature of 20 oC, the solubility was found to be 0.5 mol dm -3. What mass of KCIO 3 was crystalized out?
[K = 39, Cl = 35.5 O =16]
A
1.00g
B
10.00g
C
12.25g
D
122.50g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Given:
Solubility of KClO\(_3\) @ 45\(^0\)C = 1.5 moldm\(^{-3}\)
Solubility of KClO\(_3\) @ 20\(^0\)C = 0.5 moldm\(^{-3}\)
Difference in Solubility = 1.5 moldm\(^{-3}\) - 0.5 moldm\(^{-3}\) = 1.0 moldm\(^{-3}\)
Recall that Solubility = \(\frac{mass}{Molar mass}\times 1 dm^3\)
Also, Molar mass of KClO\(_3\) = 39 + 35.5 + (16 x 3) = 122.5g
Solubility = \(\frac{mass}{Molar mass}\times 1 dm^3\)
1.0 = \(\frac{mass}{122.5}\times 1 dm^3\)
Mass = 1.0 x 122.5 = 122.5g
Source: Myschool Past Questions Archive (Record #27479)