POST UTME REDEEMERS UNIVERSITY 2021 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A metal M has a density of 9.5 g/cm3 and an atomic mass of 65.5 g/mol. What is the volume of 1.5 mol of M in cm3?
A. 0.15 cm3
B. 0.30 cm3
C. 0.45 cm3
D. 0.60 cm3
Question 2
A 2.00 g sample of a polymer is dissolved in 100.0 mL of water. What is the concentration of the solution in g/L?
A. 2.00 g/L
B. 4.00 g/L
C. 6.00 g/L
D. 8.00 g/L
Question 3
A solution contains 0.100 M NH3 and 0.100 M HCl. What is the concentration of NH4Cl in the solution?
A. 0.100 M
B. 0.200 M
C. 0.300 M
D. 0.400 M
Question 4
A 2.5 L flask contains 1.5 atm of N2 and 1.5 atm of O2 at 25°C. What is the partial pressure of O2 in the flask?
A. 0.75 atm
B. 1.0 atm
C. 1.25 atm
D. 1.5 atm
Question 5
A sample of a polymer has a molecular weight of 100,000 g/mol. Calculate the number of monomer units in the polymer.
A. 100
B. 1000
C. 10,000
D. 100,000
Question 6
A 2.50-g sample of a hydrocarbon is burned in excess oxygen to produce 3.75 L of CO2 at 25°C and 1.00 atm. What is the empirical formula of the hydrocarbon?
A. C2H4
B. C3H6
C. C4H8
D. C5H10
Question 7
A solution of sodium chloride (NaCl) is electrolyzed u\sing a current of 5.0 A for 2.0 hours. Calculate the mass of chlorine gas produced at the anode.
A. 10 g
B. 20 g
C. 30 g
D. 40 g
Question 8
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the mass of the metal oxide produced is 2.0 g, calculate the percentage yield of the metal oxide.
A. 40%
B. 50%
C. 60%
D. 70%
Question 9
A colloidal solution of starch in water is treated with a few drops of iodine solution. Describe the change observed.
A. The solution becomes blue.
B. The solution becomes colorless.
C. The solution becomes cloudy.
D. The solution becomes clear.
Question 10
A 0.5 M solution of a strong acid is prepared by dissolving 25 g of the acid in water to make 1 L of solution. What is the molar mass of the acid?
A. 50 g/mol
B. 100 g/mol
C. 200 g/mol
D. 500 g/mol
Question 11
A 2.5 g sample of a non-metallic oxide is heated in a crucible until it decomposes completely. If 1.2 g of the oxide is left after heating, what is the percentage of the oxide that decomposed?
A. 20%
B. 30%
C. 40%
D. 50%
Question 12
A 1.00 L sample of a gas at 25°C and 1.00 atm is compressed to 2.00 atm at cons\tant temperature. What is the new volume of the gas?
A. 0.500 L
B. 1.00 L
C. 1.50 L
D. 2.00 L
Question 13
The diagram below shows a periodic table. Identify the element with atomic number 6.
A. Carbon
B. Oxygen
C. Nitrogen
D. Fluorine
Question 14
A metal M reacts with chlorine gas to form a white solid. The reaction is as follows: M + Cl2 → MX2. If 2.5 g of M reacts with 2.5 g of Cl2, what is the percentage yield of MX2 if the theoretical yield is 5 g?
A. 50%
B. 75%
C. 90%
D. 95%
Question 15
A metal (X) has a s\tandard electrode potential of +0.80 V. What is the s\tandard electrode potential of the metal (Y) that is reduced at the same rate as X?
A. +0.60 V
B. +0.80 V
C. +1.00 V
D. +1.20 V

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