POST UTME RHEMA UNIVERSITY 2019 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 1.00 L sample of a 0.500 M solution of KNO3 is electrolyzed for 2.00 hours. What is the mass of oxygen gas collected at the anode?
A. 0.500 g
B. 1.00 g
C. 1.50 g
D. 2.00 g
Question 2
A solution contains 0.5 M NaCl and 0.2 M CaCl2. Calculate the total concentration of chloride ions in the solution.
A. 0.5 M
B. 1.0 M
C. 1.2 M
D. 1.5 M
Question 3
A solution of 0.1 M NaOH is prepared by dissolving 0.1 g of NaOH in 100 mL of water. What is the concentration of the solution in g/L?
A. 0.1 g/L
B. 0.5 g/L
C. 1.0 g/L
D. 5.0 g/L
Question 4
A 0.500 M solution of $\text{H}_2\text{SO}_4$ is mixed with 100. mL of 0.100 M $\text{Ba}\( \text{OH} \)_2$. What is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.200 M
D. 0.500 M
Question 5
A reaction is said to be at equilibrium when the rates of forward and reverse reactions are equal. What is the name of the mathematical expression that describes the equilibrium cons\tant (Kc) in terms of the concentrations of reac\tants and products?
A. The Law of Mass Action
B. The Law of Conservation of Energy
C. The Law of Equilibrium Cons\tant
D. The Law of Chemical Kinetics
Question 6
A 1.0 L flask contains 0.50 M HCl. If 0.20 mol of NaOH is added to the flask, what is the resulting concentration of the solution?
A. 0.25 M
B. 0.50 M
C. 0.75 M
D. 1.0 M
Question 7
A 2.00 M solution of $\text{HCl}$ is mixed with 100. mL of 0.100 M $\text{NaOH}$. What is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.200 M
D. 0.500 M
Question 8
A sample of a hydrocarbon has a density of 0.8 g/mL and a molar mass of 42 g/mol. What is the empirical formula of the hydrocarbon?
A. C2H6
B. C3H8
C. C4H10
D. C5H12
Question 9
A metal (X) reacts with chlorine gas to form a white solid. The reaction is as follows: X + Cl2 → XCl2. If 2.50 g of X reacts with 1.00 g of Cl2, what is the molar mass of X?
A. 50.0 g/mol
B. 75.0 g/mol
C. 100 g/mol
D. 125 g/mol
Question 10
In a typical industrial process, a mixture of 2.5 g of NaOH and 2.5 g of Na2CO3 is heated to produce sodium carbonate and water. Assuming the reaction is complete, calculate the mass of sodium carbonate produced. The molar masses of NaOH and Na2CO3 are 40 g/mol and 106 g/mol, respectively.
A. 1.5 g
B. 2.5 g
C. 3.5 g
D. 4.5 g
Question 11
A metal is said to be 'noble' if it does not readily react with other elements. Which of the following metals is an example of a noble metal?
A. Gold (Au)
B. Silver (Ag)
C. Copper (Cu)
D. Zinc (Zn)
Question 12
A 2.00 L sample of a gas at 25°C and 1.00 atm is compressed to 0.500 L at the same temperature. What is the new pressure?
A. 2.00 atm
B. 4.00 atm
C. 6.00 atm
D. 8.00 atm
Question 13
A diagram of a titration setup is shown below. What is the purpose of the burette in this setup?
A. To measure the volume of the solution
B. To measure the pH of the solution
C. To mix the solution with the titrant
D. To add the titrant to the solution
Question 14
Determine the s\tandard Gibbs free energy change for the reaction: 2Ag+(aq) + 2Cl-(aq) → 2AgCl(s) at 298 K and 1 atm, given that ΔH° = -127.5 kJ/mol and ΔS° = -173.5 J/mol·K.
A. -129.5 kJ/mol
B. -127.5 kJ/mol
C. -125.5 kJ/mol
D. -123.5 kJ/mol
Question 15
A reaction is said to be exothermic if it releases heat energy. What is the sign of the enthalpy change (ΔH) for an exothermic reaction?
A. +ve
B. -ve
C. 0
D. ΔH is not related to heat energy

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