POST UTME LEAD CITY UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A metal M reacts with chlorine gas to form a compound MCl_2. The molar mass of MCl_2 is 142.6 g/mol. If the molar mass of chlorine is 35.5 g/mol, what is the molar mass of metal M?
A. 60.6 g/mol
B. 61.6 g/mol
C. 62.6 g/mol
D. 63.6 g/mol
Question 2
Determine the number of moles of oxygen gas (O2) produced at s\tandard temperature and pressure (STP) when 2.5 moles of hydrogen gas (H2) react with oxygen gas according to the balanced equation: 2H2 + O2 → 2H2O.
A. 1.25 moles
B. 2.5 moles
C. 5 moles
D. 10 moles
Question 3
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 4
A 10 mL sample of 0.5 M NaOH is titrated with 0.1 M HCl. Calculate the pH of the solution after 20 mL of HCl has been added.
A. 1
B. 2
C. 3
D. 4
Question 5
A 50.0 mL sample of 0.500 M H2SO4 is titrated with 0.500 M NaOH. Calculate the number of moles of NaOH required to reach the equivalence point.
A. 0.0250 mol
B. 0.0500 mol
C. 0.0750 mol
D. 0.100 mol
Question 6
A 2.00 L flask contains 0.500 mol of CO and 0.250 mol of O2 at 25°C. If the reaction CO(g) + 1/2O2(g) → CO2(g) is allowed to proceed until equilibrium is reached, what is the concentration of CO2 in the flask?
A. 0.125 M
B. 0.250 M
C. 0.375 M
D. 0.500 M
Question 7
A 1.00 L flask contains 0.500 mol of H2 and 0.250 mol of I2 at 25°C. If the reaction 2H2(g) + I2(g) → 2HI(g) is allowed to proceed until equilibrium is reached, what is the concentration of HI in the flask?
A. 0.125 M
B. 0.250 M
C. 0.375 M
D. 0.500 M
Question 8
A solution of 0.1 M HCl is prepared by dissolving 0.1 mol of HCl in 1 L of water. Calculate the concentration of Cl- ions in the solution.
A. 0.01
B. 0.1
C. 1
D. 10
Question 9
A 2.50 g sample of a hydrocarbon, C_xH_y, is burned in a combustion apparatus. The volume of CO2 produced is 2.00 L at STP. If the molar mass of the hydrocarbon is 42.0 g/mol, what is the empirical formula of the hydrocarbon?
A. C2H6
B. C3H8
C. C4H10
D. C5H12
Question 10
A solution contains 0.1 M NaOH and 0.2 M HCl. What is the pH of the solution?
A. 0.5
B. 1.0
C. 1.5
D. 2.0
Question 11
A 25.0 mL sample of a 0.100 M solution of sodium hydroxide (NaOH) is titrated with a 0.100 M solution of hydrochloric acid (HCl). Calculate the number of moles of HCl required to neutralize the NaOH.
A. 0.0025 moles
B. 0.0050 moles
C. 0.0075 moles
D. 0.0100 moles
Question 12
A 2.5 L flask contains 0.5 mol of an ideal gas at 27°C. Calculate the pressure of the gas u\sing the ideal gas law: PV = nRT. Given that R = 0.0821 L atm/mol K.
A. 1.7 atm
B. 2.1 atm
C. 2.5 atm
D. 3.1 atm
Question 13
A solution contains 0.1 M NaCl and 0.2 M CaCl2. What is the concentration of Cl- ions in the solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 14
A sample of gas occupies a volume of 2.5 L at a pressure of 1.5 atm and a temperature of 300 K. What is the new volume of the gas if the pressure is increased to 3.5 atm and the temperature is decreased to 200 K?
A. 1.2 L
B. 1.5 L
C. 1.8 L
D. 2.0 L
Question 15
A 10 mL sample of a 0.5 M solution of H2SO4 is titrated with 0.5 M NaOH. What is the pH of the solution after the addition of 10 mL of NaOH?
A. 1.0
B. 2.0
C. 3.0
D. 4.0

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