POST UTME BABCOCK UNIVERSITY 2023 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The rate cons\tant (k) for 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 the rate cons\tant (k) if the pre-exponential factor (A) is 1.0 x 10^10 s^\( -1 \)?
A. 1.0 x 10^\( -10 \) s^\( -1 \)
B. 1.0 x 10^\( -9 \) s^\( -1 \)
C. 1.0 x 10^\( -8 \) s^\( -1 \)
D. 1.0 x 10^\( -7 \) s^\( -1 \)
Question 2
A 25.0 mL sample of a 0.100 M solution of NaOH is mixed with 25.0 mL of a 0.100 M solution of HCl. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 3
A 2.00 g sample of a metal \( atomic mass = 50.0 g/mol \) is dissolved in 25.0 mL of 0.100 M HCl. If the reaction is complete, what is the concentration of the metal ion in the solution?
A. 0.0300 M
B. 0.0400 M
C. 0.0500 M
D. 0.0600 M
Question 4
A 0.500 L sample of a 0.100 M solution of NaOH is mixed with 0.500 L of a 0.100 M solution of HCl. What is the pH of the resulting solution?
A. 7.00
B. 7.50
C. 8.00
D. 9.00
Question 5
A polymer is a large molecule composed of many repeated subunits called monomers. Which of the following is a characteristic of a polymer?
A. It has a high melting point.
B. It has a low melting point.
C. It is soluble in water.
D. It is insoluble in water.
Question 6
The half-life of a radioactive isotope is 5.00 days. If 100.0 mg of the isotope is present initially, what is the mass remaining after 20.0 days?
A. 25.0 mg
B. 50.0 mg
C. 75.0 mg
D. 100 mg
Question 7
The half-life of a radioactive isotope is 3.00 days. If 50.0 mg of the isotope is present initially, what is the mass remaining after 9.00 days?
A. 12.5 mg
B. 25.0 mg
C. 37.5 mg
D. 50.0 mg
Question 8
A 2.0 M solution of HCl is mixed with a 1.0 M solution of NaOH. What is the concentration of the resulting solution?
A. 1.0 M
B. 1.5 M
C. 2.0 M
D. 3.0 M
Question 9
A 2.0 M solution of HCl is mixed with a 1.0 M solution of NaOH. What is the concentration of the resulting solution?
A. 1.0 M
B. 1.5 M
C. 2.0 M
D. 3.0 M
Question 10
A solution contains 0.500 M NaCl. What is the concentration of Cl^- ions in the solution?
A. ( 0.250 )
B. ( 0.500 )
C. ( 0.750 )
D. ( 1.00 )
Question 11
A 1.0 M solution of H2SO4 is mixed with a 2.0 M solution of NaOH. What is the concentration of the resulting solution?
A. 1.0 M
B. 1.5 M
C. 2.0 M
D. 3.0 M
Question 12
The pH of a solution is 4.5. What is the concentration of hydrogen ions in the solution?
A. 1.0 \times 10^{-5} M
B. 1.0 \times 10^{-4} M
C. 1.0 \times 10^{-3} M
D. 1.0 \times 10^{-2} M
Question 13
A sample of nitrogen gas (N2) has a volume of 2.5 L at a pressure of 1.0 atm and a temperature of 300 K. What is the number of moles of N2 present in the sample?
A. 0.01 mol
B. 0.05 mol
C. 0.1 mol
D. 0.5 mol
Question 14
A sample of water has a pH of 7.0. What is the concentration of hydrogen ions in the sample?
A. 1.0 \times 10^{-7} M
B. 1.0 \times 10^{-6} M
C. 1.0 \times 10^{-5} M
D. 1.0 \times 10^{-4} M
Question 15
A polymer is formed by the condensation reaction between a diol and a diacid. If the molecular weight of the diol is 180 g/mol and the molecular weight of the diacid is 150 g/mol, what is the molecular weight of the polymer formed?
A. 210 g/mol
B. 220 g/mol
C. 230 g/mol
D. 240 g/mol

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