POST UTME LAUTECH 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of sulfur (S8) is heated in a stream of oxygen gas (O2). What is the product formed when the sulfur is completely oxidized?
A. SO2
B. SO3
C. SO4^2-
D. S2O3^2-
Question 2
The s\tandard Gibbs free energy of formation of a metal oxide is -200 kJ/mol. What is the s\tandard Gibbs free energy of formation of the metal?
A. -200 kJ/mol
B. -300 kJ/mol
C. -400 kJ/mol
D. -500 kJ/mol
Question 3
A 2.5 g sample of a non-metallic element is heated in a stream of oxygen gas to produce 3.5 g of the oxide. What is the empirical formula of the oxide?
A. SO2
B. SO3
C. SO4
D. SO5
Question 4
Determine the number of unpaired electrons in the ground state of a neutral nitrogen atom (atomic number 7).
A. 1
B. 2
C. 3
D. 4
Question 5
A 2.5 M solution of sodium hydroxide (NaOH) is electrolyzed u\sing a platinum electrode. What is the mass of oxygen gas (O2) collected at the anode after 2 hours of electrolysis?
A. 0.15 g
B. 0.30 g
C. 0.45 g
D. 0.60 g
Question 6
A sample of a metal oxide has a mass of 25.0 g and a volume of 5.00 mL. If the density of the metal oxide is 4.50 g/mL, what is the mass of the metal in the sample?
A. 10.0 g
B. 12.5 g
C. 15.0 g
D. 17.5 g
Question 7
A 2.50 g sample of a metal is dissolved in 50.0 mL of 0.100 M HCl. If the reaction is complete, what is the number of moles of the metal?
A. 0.0100 mol
B. 0.0200 mol
C. 0.0300 mol
D. 0.0400 mol
Question 8
A 1.0 M solution of HCl is prepared by dissolving 36.5 g of HCl in 1000 mL of water. What is the pH of the solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 9
A metal (M) reacts with chlorine gas to form a metal chloride (MCl2). The s\tandard enthalpy of formation of MCl2(s) is -395.5 kJ/mol. Calculate the s\tandard enthalpy of formation of the metal (M).
A. -395.5 kJ/mol
B. -395.9 kJ/mol
C. -396.1 kJ/mol
D. -396.3 kJ/mol
Question 10
A sample of a gas has a volume of 2.50 L at a pressure of 1.00 atm and a temperature of 298 K. What is the volume of the gas at a pressure of 2.00 atm and a temperature of 298 K?
A. 1.00 L
B. 1.00 L
C. 1.00 L
D. 1.00 L
Question 11
A metal (M) reacts with oxygen gas to form a metal oxide (MO). The s\tandard enthalpy of formation of MO(s) is -400 kJ/mol. Calculate the s\tandard enthalpy of formation of the metal (M).
A. -400 kJ/mol
B. -400.5 kJ/mol
C. -401 kJ/mol
D. -401.5 kJ/mol
Question 12
A 0.500 M solution of NaCl is prepared by dissolving 25.0 g of NaCl in 500 mL of water. What is the concentration of Cl- ions in the solution?
A. 0.250 M
B. 0.500 M
C. 0.750 M
D. 1.00 M
Question 13
A 1.0 M solution of hydrochloric acid (HCl) is titrated with a 1.0 M solution of sodium hydroxide (NaOH). What is the pH of the solution after 25 mL of NaOH has been added?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 14
The s\tandard Gibbs free energy of formation of a metal sulfide is -100 kJ/mol. What is the s\tandard Gibbs free energy of formation of the metal?
A. -100 kJ/mol
B. -200 kJ/mol
C. -300 kJ/mol
D. -400 kJ/mol
Question 15
At 273 K, 1 mole of an ideal gas occupies a volume of 22.4 L. What is the molar volume of the gas at 300 K?
A. 22.4 L
B. 24.5 L
C. 26.8 L
D. 28.9 L

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