POST UTME CRAWFORD UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A solution contains 25.0 g of NaCl in 250.0 mL of water. Calculate the molarity of the solution.
A. 0.100 M
B. 0.100 M
C. 0.100 M
D. 0.100 M
Question 2
A 10.0 mL sample of 0.100 M sulfuric acid is mixed with 20.0 mL of 0.0500 M sodium hydroxide. What is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 3
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 becomes undefined
Question 4
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, and the reaction produces 2 moles of water per mole of polymer formed, what is the molecular weight of the polymer formed?
A. 360 g/mol
B. 420 g/mol
C. 480 g/mol
D. 540 g/mol
Question 5
A 2.0 L flask contains 1.0 mol of an ideal gas at 298 K. If the gas is heated to 373 K at cons\tant volume, what is the new pressure?
A. 2.5 atm
B. 3.0 atm
C. 3.5 atm
D. 4.0 atm
Question 6
A 5.00 g sample of a nonmetal is heated in a crucible until it is completely vaporized. If the vapor pressure of the nonmetal at 25°C is 1.00 atm, what is the molar mass of the nonmetal?
A. 20.0 g/mol
B. 30.0 g/mol
C. 40.0 g/mol
D. 50.0 g/mol
Question 7
A 2.50 L flask contains 0.250 mol of an ideal gas at 298 K. Calculate the pressure of the gas u\sing the ideal gas law.
A. 1.01 × 10^5 Pa
B. 1.01 × 10^5 Pa
C. 1.01 × 10^5 Pa
D. 1.01 × 10^5 Pa
Question 8
A sample of a metal has a density of 8.0 g/cm^3 and a volume of 2.0 cm^3. What is the mass of the sample?
A. 16 g
B. 32 g
C. 48 g
D. 64 g
Question 9
A 1.00 M solution of CaCl2 is mixed with a 1.00 M solution of Na2CO3. What is the molarity of the resulting solution?
A. 0.500 M
B. 1.00 M
C. 1.50 M
D. 2.00 M
Question 10
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. What is the s\tandard enthalpy of formation of CH4(g)?
A. -74.8 kJ/mol
B. -74.8 kJ/mol
C. -74.8 kJ/mol
D. -74.8 kJ/mol
Question 11
A solution contains 0.100 M HCl and 0.100 M NaOH. What is the pH of the solution after the addition of 25.0 mL of 0.100 M HCl?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 12
A solution of 0.1 M NaCl is electrolyzed u\sing a platinum electrode. If the current is 0.5 A, calculate the mass of chlorine gas liberated at the anode after 2 hours.
A. 0.05 g
B. 0.10 g
C. 0.15 g
D. 0.20 g
Question 13
A mixture of 2.0 g of sodium hydroxide (NaOH) and 3.0 g of hydrochloric acid (HCl) is prepared. What is the limiting reac\tant?
A. NaOH
B. HCl
C. Neither
D. Both
Question 14
A sample of $\text{Na}_2\text{SO}_4$ has a molar mass of 142 g/mol. What is the mass of 2.50 mol of $\text{Na}_2\text{SO}_4$?
A. 355 g
B. 355.5 g
C. 356 g
D. 356.5 g
Question 15
A 2.50 g sample of nitrogen gas is collected over water at 25°C and 1.00 atm. What is the volume of the gas, in liters, if the vapor pressure of water at 25°C is 23.8 torr?
A. 0.500 L
B. 0.750 L
C. 1.00 L
D. 1.25 L

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