POST UTME UI 2021 Chemistry | Objective

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Question 1
A reaction has a s\tandard enthalpy change of -200 kJ/mol. What is the s\tandard entropy change of the reaction?
A. -200 J/K/mol
B. -400 J/K/mol
C. -600 J/K/mol
D. -800 J/K/mol
Question 2
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of CaCO3(s) from the following reaction: CaO(s) + CO2(g) → CaCO3(s).
A. -1792.5 kJ/mol
B. -1792.8 kJ/mol
C. -1792.2 kJ/mol
D. -1792.1 kJ/mol
Question 3
A 1.0 L flask contains 0.1 mol of N2 and 0.2 mol of O2 at 298 K. Calculate the partial pressure of N2 u\sing the ideal gas law.
A. 1.01 x 10^3 Pa
B. 2.02 x 10^3 Pa
C. 3.03 x 10^3 Pa
D. 4.04 x 10^3 Pa
Question 4
A 2.00 M solution of H2SO4 is mixed with a 2.00 M solution of NaOH. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 5
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 x 10^3 Pa
B. 2.02 x 10^3 Pa
C. 3.03 x 10^3 Pa
D. 4.04 x 10^3 Pa
Question 6
A solution of 0.1 M NaOH is mixed with a solution of 0.1 M HCl. What is the pH of the resulting solution?
A. 7
B. 10
C. 14
D. 0
Question 7
The atomic radius of an element is 100 pm. If the element is in its ground state, what is the expected value of its atomic radius in the excited state?
A. 120 pm
B. 80 pm
C. 90 pm
D. 110 pm
Question 8
A 2.00 M solution of H2SO4 is mixed with a 2.00 M solution of NaOH. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 9
A 1.00 L solution of 0.100 M NaCl is mixed with a 1.00 L solution of 0.100 M NaOH. What is the concentration of Cl- ions in the resulting solution?
A. 0.0500 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 10
Determine the s\tandard enthalpy change for the reaction: 2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s). Given that ΔH°(Al2O3(s)) = -1675 kJ/mol, ΔH°(Al(s)) = 0 kJ/mol, and ΔH°(Fe2O3(s)) = -825 kJ/mol.
A. -2750 kJ/mol
B. -1750 kJ/mol
C. -1275 kJ/mol
D. -2250 kJ/mol
Question 11
A sample of a hydrocarbon (CnH2n) has a molecular weight of 42.0 g/mol. What is the value of n?
A. 3
B. 4
C. 5
D. 6
Question 12
A 2.00 L flask contains 1.00 mol of an ideal gas at 298 K. Calculate the work done by the gas when it expands to 4.00 L against an external pressure of 1.00 atm.
A. 10.0 J
B. 20.0 J
C. 30.0 J
D. 40.0 J
Question 13
A sample of gas has a volume of 1.5 L at 300 K. If the pressure is increased to 2 atm, what is the new volume of the gas?
A. 1.2 L
B. 1.5 L
C. 1.8 L
D. 2.0 L
Question 14
A catalyst is added to a reaction mixture containing 1.00 M H2(g) and 1.00 M I2(g). The reaction is: H2(g) + I2(g) → 2HI(g). If the rate cons\tant (k) for the reaction is 0.100 s^-1, what is the rate of reaction after 10.0 s?
A. 0.100 M/s
B. 0.200 M/s
C. 0.300 M/s
D. 0.400 M/s
Question 15
Calculate the s\tandard enthalpy change \( ΔH^circ \) for the reaction: 2NO(g) + O2(g) → 2NO2(g) at 298 K, given that ΔH^circ_f = -180.5 kJ/mol for NO(g), ΔH^circ_f = 0 kJ/mol for O2(g), and ΔH^circ_f = -99.6 kJ/mol for NO2(g).
A. -359.4 kJ/mol
B. -359.6 kJ/mol
C. -359.2 kJ/mol
D. -359.8 kJ/mol

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