POST UTME BABCOCK UNIVERSITY 2020 Chemistry | Objective

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Question 1
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 2
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 3
A sample of sulfur is burned in oxygen to produce sulfur dioxide. If 10 g of sulfur is burned, calculate the volume of oxygen required.
A. 2.5 L
B. 2.6 L
C. 2.7 L
D. 2.8 L
Question 4
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 5
Determine the number of moles of oxygen gas (O2) produced at s\tandard temperature and pressure (STP) when 2.50 g of potassium chlorate (KClO3) is decomposed according to the equation: 2KClO3(s) → 2KCl(s) + 3O2(g).
A. 0.0500 mol
B. 0.100 mol
C. 0.150 mol
D. 0.200 mol
Question 6
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
Question 7
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. Calculate the s\tandard enthalpy of formation of CO2(g) from the following reaction: C(s) + O2(g) → CO2(g).
A. -393.5 kJ/mol
B. -393.2 kJ/mol
C. -393.8 kJ/mol
D. -393.1 kJ/mol
Question 8
The s\tandard electrode potential of the Zn2+/Zn couple is -0.76 V. Calculate the s\tandard electrode potential of the Cu2+/Cu couple if the s\tandard electrode potential of the Cu2+/Cu couple is -0.34 V.
A. -0.10 V
B. -0.20 V
C. -0.30 V
D. -0.40 V
Question 9
A 2.00 L flask contains 0.500 atm of an ideal gas at 298 K. What is the volume of the gas in the flask at 323 K?
A. 1.50 L
B. 1.75 L
C. 2.00 L
D. 2.25 L
Question 10
A 0.100 M solution of Fe2+ is electrolyzed at 298 K. Calculate the number of moles of Fe3+ 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 11
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 12
A 1.00 M solution of acetic acid (CH₃COOH) is titrated with a 1.00 M solution of sodium hydroxide (NaOH). If the equivalence point is reached at 25.0 mL of NaOH, calculate the number of moles of acetic acid present.
A. 0.00500 mol
B. 0.0100 mol
C. 0.0150 mol
D. 0.0200 mol
Question 13
A metal (X) has a density of 8.96 g/cm³ and a volume of 25.0 cm³. If the metal is 92.3% pure, calculate the mass of the impurities present.
A. 0.500 g
B. 1.00 g
C. 1.50 g
D. 2.00 g
Question 14
The reaction of 2.50 g of a hydrocarbon with 50.0 mL of O2(g) at STP produces 3.00 g of CO2(g). What is the empirical formula of the hydrocarbon?
A. C2H4
B. C3H6
C. C4H8
D. C5H10
Question 15
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

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