POST UTME GREENFIELD UNIVERSITY 2018 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The s\tandard enthalpy of formation of $\text{CO}_2(g)$ is $\Delta H^\circ_{f}\( \text{CO}_2\( g \ \)) = -393.51 \text{ kJ/mol}$. What is the s\tandard enthalpy of combustion of $\text{CH}_4(g)$?
A. -890.3 kJ/mol
B. -890.3 kJ/mol
C. -890.3 kJ/mol
D. -890.3 kJ/mol
Question 2
A diagram of a simple harmonic motion is shown below. If the amplitude of the motion is 5.00 cm and the period is 2.00 s, what is the angular frequency?
A. 1.00 rad/s
B. 1.00 rad/s
C. 1.00 rad/s
D. 1.00 rad/s
Question 3
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. 1
B. 2
C. 3
D. 4
Question 4
Determine the s\tandard enthalpy of formation of $\text{CaCO}_3(s)$ from the following data: $\Delta H^\circ_{f}\( \text{CaO}\( s \ \)) = -635.09 \text{ kJ/mol}$, $\Delta H^\circ_{f}\( \text{CO}_2\( g \ \)) = -393.51 \text{ kJ/mol}$, and $\Delta H^\circ_{f}\( \text{CaCO}_3\( s \ \)) = -1206.92 \text{ kJ/mol}$.
A. -1785.69 kJ/mol
B. -1785.69 kJ/mol
C. -1785.69 kJ/mol
D. -1785.69 kJ/mol
Question 5
Calculate the s\tandard enthalpy change \( ΔH^circ \) for the reaction: 2Al(s) + Fe_2O_3(s) → 2Fe(s) + Al_2O_3(s). The s\tandard enthalpy of formation \( ΔH^circ_f \) values are: ΔH^circ_f\( Al_2O_3\( s \ \)) = -1675.7 kJ/mol, ΔH^circ_f(Al(s)) = 0 kJ/mol, ΔH^circ_f\( Fe_2O_3\( s \ \)) = -826.4 kJ/mol, ΔH^circ_f(Fe(s)) = 0 kJ/mol.
A. -1451.1 kJ/mol
B. -1451.5 kJ/mol
C. -1451.9 kJ/mol
D. -1452.3 kJ/mol
Question 6
The enthalpy change (ΔH) for the reaction: 2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s) is -853.4 kJ/mol. Calculate the s\tandard enthalpy of formation (ΔHf) of Al2O3(s) in kJ/mol.
A. -853.4 kJ/mol
B. -853.4 kJ/mol + 2 ΔHf(Al2O3(s))
C. -853.4 kJ/mol - 2 ΔHf(Al2O3(s))
D. -853.4 kJ/mol + ΔHf(Al2O3(s))
Question 7
A 0.500 L flask contains 0.250 mol of CO_2 gas at 25.0°C. If 0.250 mol of O_2 gas is added to the flask, what is the total pressure (in atm) of the gas mixture?
A. 1.01 atm
B. 1.02 atm
C. 1.03 atm
D. 1.04 atm
Question 8
A 2.50 L flask contains 0.250 mol of an ideal gas at 25.0°C. Calculate the pressure (in atm) of the gas u\sing the ideal gas law.
A. 1.01 atm
B. 1.02 atm
C. 1.03 atm
D. 1.04 atm
Question 9
A solution contains 2.50 g of NaCl. If 25.0 mL of water is added to the solution, what is the molarity of the resulting solution?
A. 0.100 M
B. 0.200 M
C. 0.300 M
D. 0.400 M
Question 10
A 25.0 mL sample of 0.500 M NaOH is titrated with 0.100 M HCl. What is the pH of the solution after the addition of 25.0 mL of HCl?
A. 1
B. 2
C. 3
D. 4
Question 11
A 2.00 g sample of an unknown hydrocarbon is burned in a bomb calorimeter. The heat of combustion is 12.5 kJ/g. What is the molar mass of the hydrocarbon?
A. 1
B. 2
C. 3
D. 4
Question 12
The s\tandard enthalpy of formation (ΔHf) of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of combustion (ΔHc) of CH4(g)?
A. -890.3 kJ/mol
B. -393.5 kJ/mol
C. -393.5 kJ/mol + 2 ΔHf(CO2(g))
D. -393.5 kJ/mol - 2 ΔHf(CO2(g))
Question 13
A diagram of a titration setup is shown below. If 25.00 mL of 0.1000 M $\text{HCl}$ is required to reach the equivalence point, what is the concentration of the $\text{NaOH}$ solution?
A. 0.1000 M
B. 0.1000 M
C. 0.1000 M
D. 0.1000 M
Question 14
A sample of a non-metallic element has a mass of 2.50 g and a volume of 5.00 mL. What is the density of the element?
A. 1.00 g/mL
B. 2.50 g/mL
C. 5.00 g/mL
D. 10.0 g/mL
Question 15
The diagram below shows a titration setup. If 25.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the concentration of the HCl solution?
A. 0.100 M
B. 0.0500 M
C. 0.200 M
D. 0.0500 M

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