POST UTME WELLSPRING UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A solution contains 0.1 M HCl and 0.2 M NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 2
A solution of 0.0500 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after 50.0 mL of NaOH has been added?
A. 2.00
B. 3.00
C. 4.00
D. 5.00
Question 3
A solution contains 0.1 M NH3 and 0.1 M NH4Cl. What is the concentration of OH- ions in the solution?
A. 1.0 x 10^\( -4 \) M
B. 1.0 x 10^\( -3 \) M
C. 1.0 x 10^\( -2 \) M
D. 1.0 x 10^\( -1 \) M
Question 4
A sample of a gas has a volume of 2.0 L at a temperature of 300 K and a pressure of 1.0 atm. What is the volume of the gas at a temperature of 400 K and a pressure of 2.0 atm?
A. 1.0 L
B. 2.0 L
C. 3.0 L
D. 4.0 L
Question 5
A solution contains 0.1 M HCl and 0.1 M NaOH. What is the pH of the solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 6
A 2.50 g sample of a compound containing only carbon and hydrogen is analyzed by combustion. The resulting CO2 and H2O are collected and weighed. If the mass of CO2 is 1.25 g and the mass of H2O is 0.750 g, what is the empirical formula of the compound?
A. CH2
B. C2H4
C. C3H6
D. C4H8
Question 7
A 10 mL sample of a solution containing 0.5 M NaCl is added to a 20 mL sample of a solution containing 0.2 M AgNO3. What is the concentration of the resulting solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 8
A 2.0 M solution of HCl is mixed with a 1.0 M solution of NaOH. What is the pH of the resulting solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 9
A sample of a non-metallic element has a mass of 2.5 g and a volume of 5 mL. If the density of the element is 2.5 g/mL, what is the molar mass of the element?
A. 10 g/mol
B. 20 g/mol
C. 30 g/mol
D. 40 g/mol
Question 10
A polymer is made up of repeating units of the following structure: H2C=CH-COOH. What is the name of this polymer?
A. Polyethylene
B. Polypropylene
C. Polyvinyl chloride
D. Polyacrylonitrile
Question 11
A 1.00 g sample of a metal is heated in a crucible until it decomposes completely. The mass of the metal oxide obtained is 1.50 g. If the metal has a molar mass of 20.0 g/mol, calculate the percentage yield of the metal oxide.
A. 50%
B. 60%
C. 70%
D. 80%
Question 12
A sample of oxygen gas is collected over water at a temperature of 25°C and a pressure of 1 atm. If the partial pressure of water vapor is 0.02 atm, what is the mole \fraction of oxygen gas?
A. 0.98
B. 0.99
C. 0.995
D. 0.999
Question 13
The reaction between sodium hydroxide (NaOH) and acetic acid (CH3COOH) is a classic example of a neutralization reaction. If 25.0 mL of 0.100 M NaOH is added to 25.0 mL of 0.100 M CH3COOH, what is the concentration of the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 14
The equilibrium cons\tant (Kc) for the reaction N2(g) + 3H2(g) ⇌ 2NH3(g) is 0.0500 at 25°C. If the initial concentrations of N2 and H2 are 0.100 M and 0.300 M, respectively, what is the concentration of NH3 after 10 minutes?
A. 0.0200 M
B. 0.0400 M
C. 0.0600 M
D. 0.0800 M
Question 15
A 2.0 L sample of a solution containing 0.2 M NaOH is titrated with 0.2 M HCl. Calculate the pH of the solution after the addition of 10 mL of HCl.
A. 1.0
B. 2.0
C. 3.0
D. 4.0

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