POST UTME REDEEMERS UNIVERSITY 2024 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 0.500 M solution of NaOH is titrated with a 0.500 M solution of HCl. What is the pH of the solution after 25.0 mL of HCl has been added?
A. 8.00
B. 7.00
C. 6.00
D. 9.00
Question 2
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of C(s) + O2(g) -> CO2(g)?
A. -393.5 kJ/mol
B. -393.5 kJ/mol + 0.5 kJ/mol
C. -393.5 kJ/mol - 0.5 kJ/mol
D. -393.5 kJ/mol + 1.0 kJ/mol
Question 3
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. If 20 mL of NaOH is added to 20 mL of HCl, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 4
The s\tandard enthalpy of formation of CO(g) is -110.5 kJ/mol. If 1 mole of CO is formed at 25°C, what is the change in entropy (ΔS) of the system?
A. -34.5 J/K
B. -35.6 J/K
C. -36.7 J/K
D. -37.8 J/K
Question 5
A metal (M) reacts with oxygen to form a metal oxide (MO). If the s\tandard enthalpy of formation of MO is -200 kJ/mol and the s\tandard enthalpy of formation of M is -100 kJ/mol, what is the s\tandard enthalpy of formation of the reaction?
A. -100 kJ/mol
B. -150 kJ/mol
C. -200 kJ/mol
D. -250 kJ/mol
Question 6
A 25 mL sample of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after the addition of 20 mL of NaOH?
A. 1
B. 2
C. 3
D. 4
Question 7
The diagram below shows a setup for the electrolysis of water. What is the purpose of the anode?
A. To produce H2 gas
B. To produce O2 gas
C. To produce H+ ions
D. To produce OH- ions
Question 8
A solution contains 0.500 M NaCl and 0.500 M NaOH. What is the concentration of OH- ions in the solution?
A. 0.250 M
B. 0.500 M
C. 0.750 M
D. 1.000 M
Question 9
A 10 g sample of a polymer is dissolved in 100 mL of a solvent. The solution has a vis\cosity of 0.5 Pa*s. What is the molar mass of the polymer?
A. 100 g/mol
B. 200 g/mol
C. 300 g/mol
D. 400 g/mol
Question 10
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 the rate cons\tant (k) if the pre-exponential factor (A) is 1.0 x 10^10 s^-1?
A. 1.0 x 10^5 s^-1
B. 1.0 x 10^6 s^-1
C. 1.0 x 10^7 s^-1
D. 1.0 x 10^8 s^-1
Question 11
A solution of 0.1 M HCl is titrated with 0.1 M NaOH. If 20 mL of NaOH is added to 20 mL of HCl, what is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 12
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. If 1 mole of CO2 is formed at 25°C, what is the change in entropy (ΔS) of the system?
A. -123.4 J/K
B. -124.5 J/K
C. -125.6 J/K
D. -126.7 J/K
Question 13
Determine the s\tandard enthalpy of formation of CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol, ΔHf(C(s)) = 0 kJ/mol.
A. -1206.60 kJ/mol
B. -1206.61 kJ/mol
C. -1206.59 kJ/mol
D. -1206.62 kJ/mol
Question 14
A sample of CO2 gas is collected over water at a temperature of 25°C and a pressure of 1.00 atm. What is the partial pressure of CO2 in the gas mixture?
A. 0.90 atm
B. 0.95 atm
C. 0.99 atm
D. 1.00 atm
Question 15
The half-life of a radioactive subs\tance is 5.00 days. If 100.0 g of the subs\tance initially exists, what is the mass of the subs\tance remaining after 20.0 days?
A. 25.0 g
B. 50.0 g
C. 75.0 g
D. 100.0 g

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: