POST UTME OAU 2017 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 0.1 M solution of HCl is titrated with a 0.1 M solution of NaOH. Calculate the pH of the solution after 25 mL of NaOH has been added.
A. 1
B. 2
C. 3
D. 4
Question 2
A 0.1 M solution of sodium chloride (NaCl) is prepared by dissolving 5.0 g of NaCl in 100 mL of water. What is the molarity of the resulting solution?
A. 0.05 M
B. 0.1 M
C. 0.5 M
D. 1.0 M
Question 3
The s\tandard enthalpy of formation (ΔHf) for the reaction 2H2(g) + O2(g) → 2H2O(l) is -572 kJ/mol. If 2.5 mol of H2 gas is burned in a bomb calorimeter, what is the heat released?
A. -1430 kJ
B. -1435 kJ
C. -1440 kJ
D. -1445 kJ
Question 4
A 25 mL sample of 0.5 M NaOH is mixed with 25 mL of 0.5 M HCl. What is the concentration of the resulting solution?
A. 0.5 M
B. 1 M
C. 1.5 M
D. 2 M
Question 5
A sample of a metal is found to have a mass of 10.0 g and a volume of 2.0 cm^3. If the density of the metal is 5.0 g/cm^3, what is the molar mass of the metal?
A. 50 g/mol
B. 100 g/mol
C. 150 g/mol
D. 200 g/mol
Question 6
A metal (X) has a density of 8.0 g/cm3 and a molar mass of 120 g/mol. What is the volume of 2.5 g of X in cm3?
A. 0.5 cm3
B. 1.0 cm3
C. 2.0 cm3
D. 4.0 cm3
Question 7
A 2.5 M solution of sulfuric acid (H2SO4) is prepared by dissolving 125 g of H2SO4 in water to make 1 L of solution. What is the concentration of the solution in units of molarity?
A. 2.5 M
B. 5.0 M
C. 1.25 M
D. 0.5 M
Question 8
A solution of sodium chloride (NaCl) is prepared by dissolving 35.5 g of NaCl in 100 g of water at 25°C. Calculate the molality of the solution.
A. 0.5 m
B. 1.0 m
C. 1.5 m
D. 2.0 m
Question 9
A sample of CO2 gas occupies a volume of 2.5 L at a pressure of 1.0 atm and a temperature of 20°C. What is the volume of the gas at a pressure of 2.0 atm and a temperature of 30°C?
A. 1.0 L
B. 2.0 L
C. 3.0 L
D. 4.0 L
Question 10
Determine the s\tandard electrode potential of the cell represented by the following reaction: MnO4- + 8H+ + 5e- → Mn2+ + 4H2O. Given that the s\tandard electrode potential of the MnO4-/Mn2+ couple is +1.23 V.
A. +1.23 V
B. +1.48 V
C. +1.93 V
D. +2.38 V
Question 11
A 0.500 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 torr, what is the partial pressure of the gas?
A. 0.980 atm
B. 1.00 atm
C. 1.02 atm
D. 1.05 atm
Question 12
A 0.1 M solution of HCl is titrated with a 0.1 M solution of NaOH. Calculate the pH of the solution after 50 mL of NaOH has been added.
A. 2
B. 3
C. 4
D. 5
Question 13
A solution of glu\cose (C6H12O6) is prepared by dissolving 10 g of glu\cose in 100 g of water at 25°C. Calculate the freezing point of the solution.
A. -0.5°C
B. -1.0°C
C. -1.5°C
D. -2.0°C
Question 14
A 2.5 g sample of a non-metallic element (X) is found to have a mass of 2.0 g after being heated in a stream of oxygen gas. If the molar mass of X is 40 g/mol, what is the empirical formula of the oxide formed?
A. X2O3
B. X2O5
C. XO2
D. XO3
Question 15
A 0.500 L sample of a solution containing 0.100 M $\text{NaOH}$ is mixed with 0.500 L of a solution containing 0.100 M $\text{HCl}$. What is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M

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