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Chemistry
UTME / JAMB 2015
Atomic Structure and Periodic Table
Solution
Chlorine consisting of two isotope of mass number 35 and 37 in the ratio 3:1 has an atomic mass of 35.5. Calculate the relative abundance of the isotope of mass number 37
A
20
B
25
C
60
D
75
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Let the relative abundance of the energy with mass 37 be
Total relative abundance of the isotope of mass 359100-k)
Total mass of isotope of mass 37-37x, while that of 35-359(100x)
-37x + 3500 − 35 − 35.5
-37x + 3500 − 35n − 35.5
Mean mass of chlorine atom − (2n + 3500)/ ÷ 100
= 35.5
2x + 3500 − 3550yx = 50/2
Source: Myschool Past Questions Archive (Record #41234)
Chemistry
UTME / JAMB 2015
Matter & Separation Techniques
Solution
The principal constituent of natural gas is
A
methane
B
ethane
C
propane
D
Butane
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Methane CH4.A. is the principal and commercial constituent natural gas. Option B,C,D are also constituent of natural gas but they are not commercial and of economic importance
Source: Myschool Past Questions Archive (Record #41235)
Chemistry
UTME / JAMB 2015
Electrochemistry and Redox
Solution
In the electrolysis of CuSo4(g) using platinum electrode the reaction at the anode is
A
4H+ 4e - 2H2
B
4OH= 4e- + 2H2O + O2
C
2OH - 2e- = 2OH
D
2OH- + 2OH = 2H2O + O2
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
40H − 4e → 2H2O + O2is the reaction of sun at the anode in the electrolysis of CuSO4 (g) using platinum particles. Option A,C,D are not formed as a result of the equation
Source: Myschool Past Questions Archive (Record #41237)
Chemistry
UTME / JAMB 2015
Atomic Structure and Periodic Table
Solution
S block elements of the periodic table one made up of
A
groups 1, 2, 3
B
groups 1, and 2
C
group 3
D
group 3 to 7
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
S block elements only are made up of group 1 and 2 options A,C,D takes place of the other blocks in the periodic table p,d,f etc.
Source: Myschool Past Questions Archive (Record #41238)
Chemistry
UTME / JAMB 2015
Acids, Bases, and Salts
Solution
The oxidation state of sulphur on H2SO4 acid is
A
-4
B
+6
C
4
D
-8
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
In SO4. The state of oxygen oxidation number is -2. Options A,C,D do not belong to the oxidation state in SO4
Source: Myschool Past Questions Archive (Record #41240)
Chemistry
UTME / JAMB 2015
Electrochemistry and Redox
Solution
In the electrolysis of brine the anode is
A
platinum
B
copper
C
zinc
D
carbon
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
In the industrial of brine carbon is the anode while mercury is the cathode. Options of A, B, C are not used in brine solution because they are alloy of mercury
Source: Myschool Past Questions Archive (Record #41241)
Chemistry
UTME / JAMB 2015
Stoichiometry & Mole Concept
Solution
Calculate the relative molecular mass of Limestone CaCO3, (Ca = 40, C =12, O = 16)
A
56
B
100
C
76
D
90
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
One molecule of CaCO has 1Ca, 1C and 30 atom relative molecular mass of CaCO3
1 × Ar of Ca +1 × Ar of C +3 × Ar of O
(1 × 40 + 1 × 12 + 3 × 1)
40 + 12 + 48
=100
Option A,C and D will not give 100
Source: Myschool Past Questions Archive (Record #41243)
Chemistry
UTME / JAMB 2015
Matter & Separation Techniques
Solution
When steam is passed over red hot carbon the substances produced are
A
hydrogen and trioxocarbonate (IV) acid
B
hydrogen, oxygen and carbon (IV) oxide
C
hydrogen and carbon (ii) oxide
D
hydrogen and carbon (IV) oxide
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Hydrogen and carbon (ii) oxide will be formed when red steam is passed ever red-hot carbon. Option A,B,D are not produced through this process
Source: Myschool Past Questions Archive (Record #41245)
Chemistry
WAEC / WASSCE 2015
Matter & Separation Techniques
The negatively charged particle in an atom is the
A
Electron
B
Neutron
C
Positron
D
Proton
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 #45736)
Chemistry
WAEC / WASSCE 2015
Matter & Separation Techniques
How many orbits are contained in an atom with atomic number 13?
A
7
B
6
C
5
D
3
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 #45737)
Chemistry
WAEC / WASSCE 2015
Stoichiometry & Mole Concept
The Van der waals' forces are dominant intermolecular forces in_______?
A
Ammonium chloride
B
Chlorine
C
Sodium chloride
D
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 #45738)
Chemistry
WAEC / WASSCE 2015
Matter & Separation Techniques
The compound formed between 14X and 16Y is _______?
A
XY
B
XY2
C
X2Y
D
X4Y6
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 #45739)
Chemistry
WAEC / WASSCE 2015
Stoichiometry & Mole Concept
The shape of a molecule of water is _______?
A
Non-linear
B
Octahedral
C
Pyramidal
D
Tetrahedral
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 #45740)
Chemistry
WAEC / WASSCE 2015
Atomic Structure and Periodic Table
Solution
A metallic ion Z\(^{2+}\) with an inert gas structure contains 18 electrons. How many protons are contained in this ion?
A
20
B
18
C
16
D
2
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The number of electron would have been equal to number of proton if the atom were a neutral atom or represented as Z without Z\(^{2+}\). But because it is Z\(^{2+}\), carrying +2, meaning 2electrons were given out, therefore number of protons will be more than number electron by 2. i.e number of electron + 2 = 18 + 2 = 20. Therefore, the number of protons will be 20.
Source: Myschool Past Questions Archive (Record #45742)
Chemistry
WAEC / WASSCE 2015
Organic Chemistry
Solution
Which of the following pairs of compounds belongs to the same homologous series?
A
C3H8 and C3H6
B
C4H10 and C5H10
C
C2H4 and C4H10
D
C2H6 and C4H10
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
both ethane and butane are in the same homologous series.( alkanes)
Source: Myschool Past Questions Archive (Record #45744)