POST UTME GREENFIELD UNIVERSITY 2017 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A metal alloy contains 80% copper and 20% zinc. If 100 g of the alloy is melted and cast into a ingot, what is the mass of copper in the ingot?
A. 50 g
B. 60 g
C. 70 g
D. 80 g
Question 2
A 1.0 M solution of hydrochloric acid is prepared by dissolving 36.5 g of hydrochloric acid in 250 mL of water. What is the concentration of the solution in moles per liter?
A. 0.1 M
B. 0.5 M
C. 1.0 M
D. 2.5 M
Question 3
A 1.00 L sample of a gas at 25°C and 1 atm is collected over water at 25°C. If the partial pressure of water vapor is 0.031 atm, what is the volume of the gas at STP?
A. 1.00 L
B. 1.00 L - 0.031 L
C. 1.00 L + 0.031 L
D. 1.00 L x \( 1 atm / 1 atm \)
Question 4
The reaction between chlorine gas and potassium iodide is represented by the equation: 2KI(s) + Cl2(g) → 2KCl(s) + I2(s). If 2.5 g of KI is reacted with an excess of Cl2, calculate the number of moles of I2 produced.
A. 0.25 mol
B. 0.5 mol
C. 0.75 mol
D. 1.0 mol
Question 5
A 10.0 mL sample of a 0.100 M solution of a strong acid is titrated with 0.100 M NaOH. Calculate the number of moles of NaOH required to reach the equivalence point.
A. 0.0050 mol
B. 0.010 mol
C. 0.015 mol
D. 0.020 mol
Question 6
The reaction of an alkene with a strong acid, such as sulfuric acid, results in the formation of an alkyl hydrogen sulfate. Which of the following alkenes will react with sulfuric acid to form the corresponding alkyl hydrogen sulfate?
A. CH2=CH2
B. CH3CH=CH2
C. CH3CH2CH=CH2
D. CH3CH2CH2CH=CH2
Question 7
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1.5 g of carbon at 298 K.
A. -589.25 kJ
B. -589.75 kJ
C. -590.25 kJ
D. -590.75 kJ
Question 8
The electrolysis of a solution of sulfuric acid produces hydrogen gas at the cathode and oxygen gas at the anode. If the electrolysis is carried out u\sing a current of 1.5 A for 1.5 hours, calculate the volume of oxygen gas produced at STP.
A. 0.5 L
B. 1.0 L
C. 2.0 L
D. 4.0 L
Question 9
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is initially present, how much will remain after 20 years?
A. 12.5 g
B. 25.0 g
C. 37.5 g
D. 50.0 g
Question 10
Determine the s\tandard enthalpy of formation of the compound CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol, ΔHf(C(s)) = 0 kJ/mol.
A. -178.18 kJ/mol
B. -178.18 kJ/mol
C. -178.18 kJ/mol
D. -178.18 kJ/mol
Question 11
The reaction between chlorine gas and sodium hydroxide solution is a classic example of a redox reaction. Write the balanced chemical equation for this reaction.
A. \text{Cl}_2 + 2\text{NaOH} \rightarrow 2\text{NaCl} + \text{H}_2\text{O}
B. \text{Cl}_2 + 2\text{NaOH} \rightarrow \text{NaCl} + \text{NaOCl} + \text{H}_2\text{O}
C. \text{Cl}_2 + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}
D. \text{Cl}_2 + 2\text{NaOH} \rightarrow \text{NaCl} + \text{NaOCl}
Question 12
A 2.0 M solution of H2SO4 is mixed with a 1.0 M solution of NaOH. Calculate the number of moles of NaHSO4 produced.
A. 0.5 mol
B. 1.0 mol
C. 1.5 mol
D. 2.0 mol
Question 13
A solution of HCl is prepared by dissolving 25 g of HCl in 100 mL of water. What is the concentration of the solution in M?
A. 0.25 M
B. 0.50 M
C. 0.75 M
D. 1.00 M
Question 14
Determine the s\tandard enthalpy of formation of CO2(g) from the following data: ΔH°f(CO2(g)) = -393.5 kJ/mol, ΔH°f(C) = 0 kJ/mol, ΔH°f(O2(g)) = 0 kJ/mol.
A. -393.5 kJ/mol
B. -393.5 kJ/mol + 0 kJ/mol
C. -393.5 kJ/mol - 0 kJ/mol
D. -393.5 kJ/mol + 0 kJ/mol + 0 kJ/mol
Question 15
A solution contains 0.0500 M H2SO4 and 0.0500 M NaOH. Calculate the pH of the solution.
A. 1.00
B. 1.00
C. 1.00
D. 1.00

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