POST UTME AL-HIKMAH UNIVERSITY 2021 Chemistry | Objective

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Question 1
A 2.0 L flask contains 0.5 mol of CO2 at 298 K. What is the partial pressure of CO2 in the flask?
A. 0.1 atm
B. 0.2 atm
C. 0.3 atm
D. 0.4 atm
Question 2
The s\tandard electrode potential for the reaction Zn2+ + 2e- → Zn is -0.76 V. What is the s\tandard electrode potential for the reaction Zn → Zn2+ + 2e-?
A. 0.76 V
B. -0.76 V
C. 1.52 V
D. -1.52 V
Question 3
A 0.5 M solution of HCl is mixed with a 0.5 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 4
A 2.0 L flask contains 0.5 mol of an ideal gas at 300 K. Calculate the work done by the gas when it expands from 2.0 L to 4.0 L against a cons\tant external pressure of 1.0 atm.
A. 2.0 J
B. 4.0 J
C. 6.0 J
D. 8.0 J
Question 5
A solution contains 2.5 g of $\text{NaCl}$ per 100 mL of solution. What is the molarity of the solution?
A. 0.1 M
B. 0.2 M
C. 0.5 M
D. 1 M
Question 6
Determine the rate cons\tant (k) for the reaction: 2NO(g) + O2(g) → 2NO2(g), given that the initial concentrations of NO and O2 are 0.1 M and 0.2 M, respectively, and the rate of disappearance of NO is 0.05 M/s after 10 minutes.
A. 0.05 min^-1
B. 0.1 min^-1
C. 0.2 min^-1
D. 0.3 min^-1
Question 7
A 2.0 g sample of a polymer is dissolved in 100 mL of a solvent. If the density of the solution is 1.2 g/mL, what is the molar mass of the polymer?
A. 100 g/mol
B. 200 g/mol
C. 500 g/mol
D. 1000 g/mol
Question 8
A 2.5 L flask contains 0.25 mol of an ideal gas at 298 K. Calculate the pressure of the gas u\sing the ideal gas law.
A. 1.01 × 10^5 Pa
B. 2.02 × 10^5 Pa
C. 3.03 × 10^5 Pa
D. 4.04 × 10^5 Pa
Question 9
A 2.5 L flask contains 0.5 mol of $\text{O}_2$ at 25°C. What is the partial pressure of $\text{O}_2$ in the flask?
A. 0.5 atm
B. 1 atm
C. 2 atm
D. 5 atm
Question 10
A 50 mL sample of a 0.2 M solution of sodium carbonate (Na2CO3) is titrated with a 0.5 M solution of hydrochloric acid (HCl). Calculate the pH of the resulting solution after the addition of 20 mL of the acid.
A. 1
B. 2
C. 3
D. 4
Question 11
Determine the number of moles of acetic acid (CH3COOH) that can be obtained from 250 mL of a 0.5 M solution of sodium acetate (CH3COONa) when it is mixed with 100 mL of 1 M hydrochloric acid (HCl).
A. 0.125 mol
B. 0.25 mol
C. 0.5 mol
D. 1 mol
Question 12
The half-reaction Zn → Zn2+ + 2e- has a s\tandard electrode potential of -0.76 V. What is the s\tandard electrode potential for the reaction Zn2+ + 2e- → Zn?
A. 0.76 V
B. -0.76 V
C. 1.52 V
D. -1.52 V
Question 13
The s\tandard electrode potential for the reaction Zn2+ + 2e- → Zn is -0.76 V. What is the s\tandard electrode potential for the reaction Zn → Zn2+ + 2e-?
A. 0.76 V
B. -0.76 V
C. 1.52 V
D. -1.52 V
Question 14
The half-reaction Zn → Zn2+ + 2e- has a s\tandard electrode potential of -0.76 V. What is the s\tandard electrode potential for the reaction Zn2+ + 2e- → Zn?
A. 0.76 V
B. -0.76 V
C. 1.52 V
D. -1.52 V
Question 15
Determine the number of moles of $\text{CO}_2$ produced when 2.5 moles of $\text{CaC}_2$ react with excess $\text{H}_2\text{O}$ according to the equation $\text{CaC}_2 + 2\text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2 + \text{C} + \text{CO}_2$.
A. 1.25
B. 2.5
C. 5
D. 10

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