POST UTME MOUNTAIN TOP UNIVERSITY 2025 Chemistry | Objective

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Question 1
The reaction between sodium hydroxide and hydrochloric acid is an example of a ______________ reaction.
A. neutralization reaction
B. oxidation-reduction reaction
C. combustion reaction
D. decomposition reaction
Question 2
The polymerization of styrene to form polystyrene is an example of a ______________ reaction.
A. chain reaction
B. addition reaction
C. condensation reaction
D. substitution reaction
Question 3
The half-life of a radioactive subs\tance is 5 years. If the initial amount of the subs\tance is 100 g, what is the amount of the subs\tance remaining after 10 years?
A. 12.5 g
B. 25 g
C. 50 g
D. 100 g
Question 4
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after the addition of 25.0 mL of NaOH.
A. 2.00
B. 3.00
C. 4.00
D. 5.00
Question 5
A 25 mL sample of a solution containing 0.5 M HCl is titrated with 0.5 M NaOH. Calculate the number of moles of HCl that react with NaOH.
A. 0.025
B. 0.05
C. 0.075
D. 0.1
Question 6
A sample of an ideal gas is heated at cons\tant volume. Which of the following statements is true about the change in entropy of the gas?
A. The entropy of the gas increases.
B. The entropy of the gas decreases.
C. The entropy of the gas remains cons\tant.
D. The entropy of the gas cannot be determined.
Question 7
The atomic radius of an element increases as you move down a group in the periodic table. What is the reason for this tr\end?
A. The atomic radius increases due to the addition of new energy levels.
B. The atomic radius increases due to the increase in the number of protons.
C. The atomic radius increases due to the decrease in the effective nuclear charge.
D. The atomic radius increases due to the increase in the number of electrons.
Question 8
The rate cons\tant (k) of a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/mol*K, and the temperature (T) is 300 K, what is the value of A if k = 0.05 s^\( -1 \)?
A. 1.23 x 10^7 s^\( -1 \)
B. 1.23 x 10^6 s^\( -1 \)
C. 1.23 x 10^5 s^\( -1 \)
D. 1.23 x 10^4 s^\( -1 \)
Question 9
The electrolysis of a molten ionic compound, such as sodium chloride, produces sodium metal and chlorine gas. What is the half-reaction at the cathode?
A. Na^+ + e^- → Na
B. Cl^- + e^- → Cl
C. Na^+ + e^- → Na^2+
D. Cl^- + e^- → Cl^2-
Question 10
A 1.0 M solution of HCl is mixed with a 1.0 M solution of NaOH. Calculate the concentration of the resulting solution.
A. 0.50 M
B. 0.75 M
C. 1.0 M
D. 1.25 M
Question 11
The compound with the molecular formula C2H6O is an example of a ______________.
A. aldehyde
B. ketone
C. alcohol
D. ether
Question 12
A sample of gas has a volume of 2.5 L at a pressure of 1.5 atm. What is the temperature of the gas in Kelvin if its volume is increased to 5.0 L?
A. 300 K
B. 400 K
C. 500 K
D. 600 K
Question 13
Determine the pH of a 0.1 M solution of acetic acid (CH3COOH) at 25°C.
A. 4.75
B. 5.75
C. 6.75
D. 7.75
Question 14
A polymer has a molecular weight of 50,000 g/mol and a degree of polymerization of 500. Calculate the molar mass of the repeating unit.
A. 100 g/mol
B. 200 g/mol
C. 50 g/mol
D. 25 g/mol
Question 15
A 25 mL sample of a solution containing 0.5 M HCl is titrated with 0.5 M NaOH. Calculate the number of moles of HCl that react with NaOH.
A. 0.025
B. 0.05
C. 0.075
D. 0.1

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