POST UTME RSU 2018 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of CO2 is collected over water at a temperature of 25°C and a pressure of 1 atm. What is the partial pressure of CO2 in the gas mixture?
A. \( P_{CO_2} = P_{total} - P_{H_2O} \)
B. \( P_{CO_2} = P_{total} + P_{H_2O} \)
C. \( P_{CO_2} = P_{total} \times P_{H_2O} \)
D. \( P_{CO_2} = P_{total} div P_{H_2O} \)
Question 2
Determine the molar mass of a polymer with the following composition: 60% polyethylene (C2H4), 20% polypropylene (C3H6), and 20% polystyrene (C8H8).
A. 60 g/mol
B. 120 g/mol
C. 180 g/mol
D. 240 g/mol
Question 3
A 2.50-g sample of a metal oxide is heated in a crucible until it decomposes completely. The mass of the metal obtained is 1.25 g. If the metal oxide has a molar mass of 120 g/mol and the metal has a molar mass of 40 g/mol, calculate the percentage yield of the metal.
A. 50%
B. 60%
C. 70%
D. 80%
Question 4
A 0.5 mol sample of CO2 is placed in a 1 L flask at 25°C. Calculate the pressure of the gas u\sing the ideal gas law.
A. 101325 Pa
B. 202650 Pa
C. 303875 Pa
D. 405100 Pa
Question 5
A 2.0 L flask contains 0.5 mol of an ideal gas at 25°C. If the gas is heated to 100°C, what is the new volume of the gas?
A. 4.0 L
B. 6.0 L
C. 8.0 L
D. 10.0 L
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of C(s) + O2(g) → CO2(g).
A. -393.5 kJ/mol
B. -393.5 kJ/mol + 0 kJ/mol
C. -393.5 kJ/mol - 0 kJ/mol
D. 0 kJ/mol
Question 7
A 2.0 M solution of NaOH is titrated with 1.0 M HCl. What is the pH of the solution after 20 mL of HCl has been added?
A. \( pH = \frac{1}{2} \log \frac{[NaOH]}{[HCl]} \)
B. \( pH = \frac{1}{2} \log \frac{[HCl]}{[NaOH]} \)
C. \( pH = \frac{1}{2} \log \frac{[NaOH] + [HCl]}{[NaOH]} \)
D. \( pH = \frac{1}{2} \log \frac{[HCl]}{[NaOH] + [HCl]} \)
Question 8
A 2.50 g sample of a non-metallic oxide is heated in a crucible until it decomposes completely. The mass of the residue is 1.25 g. Calculate the percentage of oxygen in the original sample.
A. 20.0%
B. 30.0%
C. 40.0%
D. 50.0%
Question 9
A catalyst is added to a reaction mixture. The reaction rate increases by a factor of 5. If the initial rate of reaction is 2.5 mol/L·s, what is the new rate of reaction?
A. 1.25 mol/L·s
B. 2.5 mol/L·s
C. 5 mol/L·s
D. 12.5 mol/L·s
Question 10
A 25.0 mL sample of 0.100 M NaOH is titrated with 0.100 M HCl. Calculate the number of moles of HCl required to reach the equivalence point.
A. 0.00250 mol
B. 0.00500 mol
C. 0.00750 mol
D. 0.0100 mol
Question 11
A sample of nitrogen gas occupies a volume of 2.5 L at a pressure of 1.5 atm and a temperature of 298 K. Calculate the number of moles of nitrogen gas present.
A. 0.2 mol
B. 0.5 mol
C. 1.0 mol
D. 2.0 mol
Question 12
A 1.0 M solution of HCl is titrated with 0.5 M NaOH. What is the pH of the solution after 25 mL of NaOH has been added?
A. \( pH = \frac{1}{2} \log \frac{[HCl]}{[NaOH]} \)
B. \( pH = \frac{1}{2} \log \frac{[NaOH]}{[HCl]} \)
C. \( pH = \frac{1}{2} \log \frac{[HCl] + [NaOH]}{[HCl]} \)
D. \( pH = \frac{1}{2} \log \frac{[NaOH]}{[HCl] + [NaOH]} \)
Question 13
The diagram below shows a simple black and white chemistry apparatus showing titration setup. Identify the part labeled A.
A. Burette
B. Beaker
C. Conical flask
D. Pipette
Question 14
A sample of a gas at 25°C and 1 atm is compressed to 5 atm. What is the new volume of the gas?
A. 0.2 L
B. 0.5 L
C. 1 L
D. 2 L
Question 15
The pH of a solution is determined by
A. concentration of hydrogen ions
B. concentration of hydroxide ions
C. concentration of acid
D. concentration of base

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub: