POST UTME RHEMA UNIVERSITY 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 10.0 cm³ sample of a gas at 25.0°C and 1.00 atm is collected over water at 25.0°C. The total pressure of the gas is 1.50 atm. Calculate the partial pressure of the gas.
A. 0.50 atm
B. 1.00 atm
C. 1.25 atm
D. 1.50 atm
Question 2
The diagram below shows the structure of a biomolecule.
A. A is a nucleus and B is a cell
B. A is a cell and B is a nucleus
C. A is a nucleus and B is a cell
D. A is a cell and B is a cell
Question 3
A 2.50 g sample of a non-metallic oxide of nitrogen is dissolved in 50.0 cm³ of water. The resulting solution has a pH of 11.50. Calculate the molar mass of the oxide.
A. 92.00 g/mol
B. 120.00 g/mol
C. 140.00 g/mol
D. 160.00 g/mol
Question 4
A solution of sodium hydroxide (NaOH) is titrated with a solution of hydrochloric acid (HCl). The initial pH of the NaOH solution is 12.00. The pH of the solution after the addition of 25.0 cm³ of HCl is 11.00. Calculate the concentration of the HCl solution.
A. 0.100 M
B. 0.200 M
C. 0.300 M
D. 0.400 M
Question 5
A 0.5 M solution of a weak acid HA is titrated with 0.5 M NaOH. If 25 mL of NaOH is required to reach the equivalence point, what is the initial concentration of HA?
A. 0.25 M
B. 0.5 M
C. 0.75 M
D. 1 M
Question 6
The diagram below shows the structure of a polymer.
A. A is a monomer and B is a polymer
B. A is a polymer and B is a monomer
C. A is a monomer and B is a polymer
D. A is a polymer and B is a polymer
Question 7
A 2.00 M solution of NaCl is prepared by dissolving 0.500 mol of NaCl in 0.250 L of water. What is the concentration of NaCl in the solution?
A. 1.00 M
B. 2.00 M
C. 2.50 M
D. 5.00 M
Question 8
A 2.50 L sample of a gas at 25°C and 1.00 atm is collected over water. If the vapor pressure of water at 25°C is 23.8 mmHg, what is the partial pressure of the gas?
A. 0.97 atm
B. 1.00 atm
C. 1.03 atm
D. 1.05 atm
Question 9
A 5.00 g sample of a metal is heated in a crucible until it decomposes completely. The mass of the metal obtained is 2.50 g. Calculate the percentage yield of the metal.
A. 50.00%
B. 60.00%
C. 70.00%
D. 80.00%
Question 10
A 0.1 M solution of NaOH is prepared by dissolving 0.1 mol of NaOH in enough water to make 1 L of solution. Calculate the mass of NaOH used in preparing the solution.
A. 10 g
B. 20 g
C. 30 g
D. 40 g
Question 11
A 2.50 M solution of HCl is prepared by dissolving 0.500 mol of HCl in 0.250 L of water. What is the concentration of HCl in the solution?
A. 1.00 M
B. 2.00 M
C. 2.50 M
D. 5.00 M
Question 12
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -393.5 kJ/mol
C. 110.5 kJ/mol
D. 393.5 kJ/mol
Question 13
A 10.0g sample of a polymer is dissolved in 100.0mL of a solvent. If the solution has a vis\cosity of 0.500Pa·s at 25°C, what is the molar mass of the polymer?
A. 1000g/mol
B. 5000g/mol
C. 10000g/mol
D. 20000g/mol
Question 14
A 2.00g sample of a compound is mixed with 10.0mL of 0.100M HCl. If the resulting solution requires 5.00mL of 0.100M NaOH for neutralization, what is the molar mass of the compound?
A. 100g/mol
B. 150g/mol
C. 200g/mol
D. 250g/mol
Question 15
A 1.00 L flask contains 0.500 mol of CO2 at 25°C. What is the partial pressure of CO2 in the flask?
A. 0.500 atm
B. 1.00 atm
C. 2.00 atm
D. 5.00 atm

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