POST UTME CRAWFORD UNIVERSITY 2022 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A reaction has a rate cons\tant of 2.0 s^-1. If the initial concentration of the reac\tant is 1.0 M, what is the concentration after 10 minutes?
A. 0.1 M
B. 0.5 M
C. 1.0 M
D. 2.0 M
Question 2
A 1.0 M solution of HCl is titrated with 1.0 M NaOH. If 20 mL of NaOH is added, what is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 3
A metal M reacts with oxygen to form a basic oxide MO. If 2.5 g of M reacts with 1.5 g of O2, what is the mass of MO formed?
A. 3.5 g
B. 4.5 g
C. 5.5 g
D. 6.5 g
Question 4
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after 50 mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 5
A solution of 0.1 M NaOH is slowly added to 50 mL of 0.1 M HCl. What is the pH of the resulting solution after 10 mL of NaOH has been added?
A. 7
B. 8
C. 9
D. 10
Question 6
A diagram of a titration setup is shown below. What is the purpose of the burette?
A. To measure the volume of the solution
B. To measure the pH of the solution
C. To measure the concentration of the solution
D. To measure the temperature of the solution
Question 7
A 2.5 g sample of a metal carbonate is heated strongly. If 1.2 g of CO2 is produced, calculate the percentage purity of the carbonate.
A. 80%
B. 85%
C. 90%
D. 95%
Question 8
A 0.1 M solution of a weak acid HA is mixed with a 0.1 M solution of a strong base NaOH. If the initial pH of the acid solution is 4.5, what is the pH of the resulting solution after the reaction is complete?
A. 4.5
B. 5.5
C. 6.5
D. 7.5
Question 9
Determine the pH of a 0.1 M solution of HCl. The dissociation cons\tant (Ka) for HCl is 10^\( -7 \).
A. 1
B. 2
C. 3
D. 4
Question 10
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 11
Determine the pH of a 0.1 M solution of HCl, given that the solubility product cons\tant (Ksp) of CaF2 is 3.9 x 10^-11.
A. 1
B. 2
C. 3
D. 4
Question 12
A metal M reacts with oxygen to form a white solid. The reaction is as follows: 4M + 3O2 → 2M2O3. If 2.5 g of M2O3 is obtained from 2.5 g of M, calculate the percentage yield of M2O3.
A. 50%
B. 60%
C. 70%
D. 80%
Question 13
Determine the s\tandard enthalpy of formation of CO2(g) from the following data: ΔH°(C(s) + O2(g) → CO2(g)) = -393.5 kJ/mol and ΔH°(H2(g) + 1/2O2(g) → H2O(l)) = -285.8 kJ/mol.
A. -677.3 kJ/mol
B. -677.3 kJ/mol
C. -677.3 kJ/mol
D. -677.3 kJ/mol
Question 14
A 0.1 M solution of H2SO4 is titrated with 0.1 M NaOH. What is the pH of the solution after 20 mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 15
The reaction 2NO(g) + O2(g) → 2NO2(g) has a rate cons\tant of 1.5 × 10^\( -3 \) s^\( -1 \) at 298 K. What is the rate of reaction if the initial concentrations of NO(g) and O2(g) are 0.10 M and 0.20 M, respectively?
A. 1.8 × 10^\( -4 \) M s^\( -1 \)
B. 1.8 × 10^\( -4 \) M s^\( -1 \)
C. 1.8 × 10^\( -4 \) M s^\( -1 \)
D. 1.8 × 10^\( -4 \) M s^\( -1 \)

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