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Chemistry
NECO SSCE 2003
Electrochemistry and Redox
Solution
What change will occur during the electrolysis of brine using carbon electrodes?
A
Chlorine will be given off at the anode
B
Oxygen gas will be given off at the anode
C
Sodium will be deposited at the cathode
D
The resulting solution, after electrolysis, will be acidic.
E
The volumes of hydrogen and chlorine given off during the same time are equal
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Chlorine is discharged as follows:
\(Cl^- \to Cl + e^-\)
\(Cl + Cl \to Cl_{2(g)}\)
This reaction occurs at the anode.
Source: Myschool Past Questions Archive (Record #43453)
Chemistry
NECO SSCE 2003
Acids, Bases, and Salts
Which metal bromide is widely used in photography?
A
calcium bromide
B
magnesium bromide
C
potassium bromide
D
silver bromide
E
sodium bromide
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 #43454)
Chemistry
NECO SSCE 2003
Electrochemistry and Redox
How many Faradays of electricity are required to liberate 9g of aluminium? [Al = 27]
A
0.1
B
0.3
C
1
D
2.7
E
3
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 #43455)
Chemistry
NECO SSCE 2003
Stoichiometry & Mole Concept
Solution
At s.t.p, a mole of chlorine occupies 22.4dm3. If the temperature is changed to 35^\circC and the pressure to 750mHg the of the new volume will be [Cl = 35.5]
A
\(\frac{760\times 22.4\times 308}{750\times 273\times 35.5} dm^3 \)
B
\(\frac{760\times 22.4\times 308}{750\times 273}dm^3 \)
C
\(\frac{750\times 22.4\times 35.5}{760\times 273}dm^3\)
D
\(\frac{760\times 22.4\times 35.5}{750\times 22.3\times 273}dm^3 \)
E
\(\frac{760\times 22.4\times 35.5}{750\times 308}dm^3 \)
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Using the general gas law, \(\frac{P_1 \times V_1}{T_1}\) = \(\frac{P_2 \times V_2}{T_2}\)
At STP, P1 = 760mmHg, V1 = 22.4dm3, T1 = 273K, P2 = 750mmHg, V2 = ? and T2 = 350C = 35 + 273 = 308K
making \(V_2\) subject of formula, then \(V_2\) = \(\frac{P_1\times V_1\times T_2}{P_2\times T_1}\)
\(V_2\) = \(\frac{760\times 22.4\times 308}{750\times 273}\)
Source: Myschool Past Questions Archive (Record #43468)
Chemistry
NECO SSCE 2003
Stoichiometry & Mole Concept
Solution
What is the concentration (mol dm\(^{-3}\)) of a solution containing 28 g of potassium hydroxide per 100 cm\(^3\) of solution? (K=39; H=1; O=16)
A
0.01
B
0.05
C
1.0
D
5.0
E
2.8
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
You can apply any of the two methods below:
METHOD 1: The use of the solubility formula, which is;
Solubility = \(\frac{mass}{Molar mass}\) X \(\frac{1000}{Volume of Solvent}\)
But Molar mass of KOH = 39 + 16 + 1 = 56g/mol
Also given; mass of KOH = 28g
Volume of Solvent used = 100cm\(^3\)
Solubility = \(\frac{28}{56}\) X \(\frac{1000}{100}\)
= 5 moldm\(^{-3}\)
METHOD 2: Using the simple proportion method
If 28g of KOH was dissolved in 100cm\(^3\) of water
then, Xg of KOH will be dissolved in 1000cm\(^3\) of water
X = \(\frac{{28}\times{1000}}{100}\)
X = 280 gdm\(^{-3}\)
Recall that Molar Concentration (mol dm\(^{-3}\)) = \(\frac{Mass Concentration}{Molar mass}\)
= \(\frac{280}{56}\)
= 5 moldm\(^{-3}\)
Kindly choose any of the methods you find easier and comprehending.
Source: Myschool Past Questions Archive (Record #43472)
Chemistry
NECO SSCE 2003
Matter & Separation Techniques
Which method is used for the purification of copper from its ore?
A
distillation
B
electrochemical
C
electrolysis
D
neutralization
E
reduction
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 #43473)
Chemistry
NECO SSCE 2003
Acids, Bases, and Salts
Ethene decolourises acidified potassium tetraoxomanganate(VII) solution. Which gas will decolourise bromine water?
A
CH4
B
C2H6
C
C3H6
D
C3H8
E
C6H6
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 #43475)
Chemistry
NECO SSCE 2003
Matter & Separation Techniques
What is formed when starch is completely hydrolysed?
A
fructose
B
glucose
C
lactose
D
maltose
E
sucrose
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 #43479)
Chemistry
NECO SSCE 2003
Organic Chemistry
Solution
Which hydrocarbon does NOT exhibit structural isomerism?
A
C3H6
B
C4H6
C
C4H8
D
C4H10
E
C5H12
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Alkenes that show structural isomerism are those with 4 carbons and above.
Source: Myschool Past Questions Archive (Record #43481)
Chemistry
NECO SSCE 2003
Acids, Bases, and Salts
Why is tetraoxosulphate(VI) acid NOT used for making carbon dioxide from calcium carbonate? It is
A
a dehydrating agent
B
a strong acid
C
an oxidising agent
D
dibasic
E
forms insoluble calcium tetraoxosulphate(Vl)
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #43482)
Chemistry
NECO SSCE 2003
Matter & Separation Techniques
Which metal is extracted from bauxite?
A
aluminium
B
calcium
C
copper
D
magnesium
E
tin
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 #43483)
Chemistry
NECO SSCE 2003
Matter & Separation Techniques
Which separation technique is routinely applied in the petroleum industry?
A
chromatography
B
distillation
C
evaporation
D
fractional crystallization
E
fractional distillation
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #43485)
Chemistry
NECO SSCE 2003
Matter & Separation Techniques
Small amounts of compounds of transition metals are sometimes added to glass during manufacture in order to make the glass
A
acquire certain colours
B
easier to melt
C
easier to mould
D
little brittle
E
more transparent
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 #43487)
Chemistry
NECO SSCE 2003
Acids, Bases, and Salts
Solution
The pH of water is 7.
What is the pH of orange juice?
A
7
B
above 10
C
below 2
D
between 5.5 and 6.5
E
between 7.5 and 8.5
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Orange juice is an acidic beverage with a typical pH value ranging between 3.3 and 4.2. However, in the context of the specific multiple-choice question provided by the examiner, the intended answer or best option to be considered is D. between 5.5 and 6.5.
Source: Myschool Past Questions Archive (Record #43488)
Chemistry
NECO SSCE 2003
Matter & Separation Techniques
Chlorine displaces bromine from aqueous potassium bromide because
A
bromine is a liquid at room temperature
B
bromine is weakly acidic.
C
bromine has a greater atomic radius than chlorine
D
chlorine is a stronger oxidising agent than bromine.
E
the density of chlorine is less than the density of bromine.
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 #43489)