POST UTME BABCOCK UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A gas at 300 K and 1 atm is compressed to 5 atm. If the initial volume is 10 L, calculate the final volume of the gas.
A. 1 L
B. 2 L
C. 3 L
D. 4 L
Question 2
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 3
A 1.00 M solution of HCl is mixed with a 0.500 M solution of NaOH. Calculate the pH of the resulting solution after the reaction is complete.
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 4
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CH4(g) from the following reaction: C(s) + 2H2(g) → CH4(g).
A. -74.8 kJ/mol
B. -74.5 kJ/mol
C. -74.2 kJ/mol
D. -75.1 kJ/mol
Question 5
The half-life of a radioactive subs\tance is 10 years. If the initial activity is 1000 Bq, calculate the activity after 20 years.
A. 100 Bq
B. 500 Bq
C. 1000 Bq
D. 2000 Bq
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -130.5 kJ/mol
C. -150.5 kJ/mol
D. -170.5 kJ/mol
Question 7
A 2.00 M solution of sodium hydroxide (NaOH) is electrolyzed u\sing a platinum electrode. If the cell potential is 2.50 V, calculate the number of moles of oxygen gas produced at the anode.
A. 0.0100 mol
B. 0.0200 mol
C. 0.0300 mol
D. 0.0400 mol
Question 8
A 1.00 M solution of H2O is electrolyzed at 298 K. Calculate the number of moles of O2 gas produced at the anode after 2.50 hours, given that the cell potential is 2.00 V.
A. 0.0125 mol
B. 0.0250 mol
C. 0.0500 mol
D. 0.100 mol
Question 9
A polymer (A) has a molecular weight of 50,000 g/mol and a degree of polymerization of 200. If the polymer is 80% crystalline, calculate the number of moles of the repeating unit.
A. 0.00250 mol
B. 0.00500 mol
C. 0.00750 mol
D. 0.0100 mol
Question 10
A 2.50 g sample of magnesium metal is heated in air to produce a compound with the formula MgO. If the molar mass of magnesium is 24.31 g/mol and the molar mass of oxygen is 16.00 g/mol, calculate the number of moles of oxygen that react with the magnesium.
A. 0.0625 mol
B. 0.125 mol
C. 0.250 mol
D. 0.500 mol
Question 11
A 2.0 M solution of H2SO4 is prepared by dissolving 80 g of H2SO4 in 1000 mL of water. Calculate the number of moles of H2SO4 in the solution.
A. 0.4 mol
B. 0.8 mol
C. 1.2 mol
D. 1.6 mol
Question 12
A solution of 0.100 M NaOH is titrated with 0.100 M HCl. What is the pH of the solution after 25.0 mL of HCl has been added?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 13
A polymer is formed by the condensation reaction between a diol and a diisocyanate. The molecular weight of the polymer is 50000 g/mol. If the molecular weight of the diol is 62 g/mol and that of the diisocyanate is 168 g/mol, calculate the number-average degree of polymerization (DPn) of the polymer.
A. 217
B. 218
C. 219
D. 220
Question 14
A 0.500 M solution of NaOH is mixed with a 0.250 M solution of HCl. Calculate the concentration of the resulting solution after the reaction is complete.
A. 0.125 M
B. 0.250 M
C. 0.375 M
D. 0.500 M
Question 15
Calculate the molar mass of a compound that contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. The atomic masses of carbon, hydrogen, and oxygen are 12.01 g/mol, 1.008 g/mol, and 16.00 g/mol, respectively.
A. 48.0 g/mol
B. 52.0 g/mol
C. 56.0 g/mol
D. 60.0 g/mol

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