Chemistry Exam Past Questions and Answers | JAMB, WAEC and NECO

Chemistry is the study of the substances that make up matter. It looks at their properties, how they react with each other, and how these reactions can create new substances.

Question 1281: Iron galvanized with zinc is cathodically protected from corrosion. This is because? Options:
A) zinc has a more positive oxidation potential than iron
B) zinc has less positive oxidation potential than iron
C) bith have the same oxidation potential
D) zinc is harder than iron
Show Answer
The correct answer is B .
Question 1282: Which of the following represent hybridization in ethyne? Options:
A) Sp²
B) Sp²d
C) Sp³
D) Sp
Show Answer
The correct answer is D .
Question 1283: The number of atoms in one mole of a substance is equal to? Options:
A) the atomic number
B) the avogadro number
C) the gas constant
D) the number of neutrons
E) the number of electrons
Show Answer
The correct answer is B .
Question 1284:
When 10g of sodium hydroxide is dissolved in 1000cm³ of water, the sodium formed is approximately
[Na = 23, H = 1, O = 16]
Options:
A) 0.01 mol dm^-3
B) 0.10 mol dm^-3
C) 0.25 mol dm^-3
D) 0.50 mol dm^-3
Show Answer
The correct answer is C .
Question 1285:
A given amount of gas occupies 10.0dm5 at 4atm and 273°C. The number of moles of the gas present is [Molar volume of gas at s.t.p = 22.4dm $^{3}$ ]
Options:
A) 0.89 mol
B) 1.90 mol
C) 3.80 mol
D) 5.70 mol
Show Answer
The correct answer is A .
Question 1286:
What technique is suitable for separating a binary solution of potassium chloride and potassium trioxochlorate (V)?
Options:
A) Fractional crystallization
B) Fractional distillation
C) Filtration
D) Evaporation
Show Answer
The correct answer is A .
Question 1287:
GAS CO $_{2}$ N $_{2}$
O $_{2}$
% BY VOLUME 4 72 24
The above table shows the compositions of the atmosphere of planet X. Which of these gases are present inhigherpercentages on earth?
Options:
A) CO $_{2}$ and O $_{2}$
B) N $_{2}$ and CO $_{2}$
C) CO $_{2}$ , O $_{2}$ and N $_{2}$
D) O $_{2}$ and N $_{2}$
Show Answer
The correct answer is D .
Question 1288:
The reactions below represent neutralization reaction, in which of them is the value of H highest?
Options:
A) CH $_{3}$ CH $_{2}$ COOH + KOH → CH $_{3}$ CH $_{2}$ COOK + H $_{2}$ O
B) NH $_{4}$ OH + HCL → NH $_{4}$ + H $_{2}$ O
C) NaOH + HCL → NaCL + H $_{2}$ O
D) CH $_{3}$ COOH + NaOH → CH $_{3}$ COONa + H $_{2}$ O
Show Answer
The correct answer is C .
Question 1289:
The diagram above best illustrates the effect of decrease in
Options:
A) concentration
B) temperature
C) surface area
D) pressure
Show Answer
The correct answer is A .
Question 1290: Which of the following CANNOT be obtained by fractional distillation of petroleum? Options:
A) Ether
B) Methane
C) Butane
D) Ethene
E) Hydrogen
Show Answer
The correct answer is E .

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GAS	CO $_{2}$	N $_{2}$	O $_{2}$
% BY VOLUME	4	72	24