POST UTME UNILAG 2017 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1 mole of methane (CH4) at 298 K.
A. -891 kJ/mol
B. -891.5 kJ/mol
C. -892 kJ/mol
D. -892.5 kJ/mol
Question 2
A 2.0 L flask contains 1.0 mol of an ideal gas at 298 K. What is the pressure of the gas?
A. 101.3 kPa
B. 202.6 kPa
C. 303.9 kPa
D. 405.2 kPa
Question 3
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the mass of the metal oxide produced is 2.1 g, calculate the percentage yield of the metal oxide.
A. 65%
B. 70%
C. 75%
D. 80%
Question 4
The reaction between sodium hydroxide and hydrochloric acid is represented by the equation: NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l). What is the type of reaction?
A. Synthesis reaction
B. Decomposition reaction
C. Single displacement reaction
D. Double displacement reaction
Question 5
A diagram of a redox reaction is shown below. What is the role of the catalyst in this reaction?
A. To speed up the reaction.
B. To slow down the reaction.
C. To change the direction of the reaction.
D. To change the products of the reaction.
Question 6
A 10.0 g sample of a metal is heated in air to produce a metal oxide. The mass of the metal oxide produced is 12.0 g. What is the percentage yield of the reaction?
A. 80%
B. 90%
C. 92%
D. 96%
Question 7
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. If the mass of the metal oxide produced is 2.1 g, calculate the percentage yield of the metal oxide.
A. 65%
B. 70%
C. 75%
D. 80%
Question 8
A redox reaction involves the transfer of 2 electrons. If the s\tandard reduction potential of the oxidizing agent is +0.5 V, what is the s\tandard reduction potential of the reducing agent?
A. -0.5 V
B. -0.6 V
C. -0.7 V
D. -0.8 V
Question 9
The s\tandard enthalpy of formation of CO2 is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1 mole of methane (CH4) at 298 K.
A. -891 kJ/mol
B. -891.5 kJ/mol
C. -892 kJ/mol
D. -892.5 kJ/mol
Question 10
A sample of benzene (C6H6) has a mass of 12.0 g. Calculate the number of moles of benzene present in the sample.
A. 0.154 mol
B. 0.1545 mol
C. 0.1541 mol
D. 0.1549 mol
Question 11
The atomic radius of an element in the periodic table increases down a group and decreases across a period. What is the reason for this tr\end?
A. The atomic radius increases down a group due to the addition of new energy levels, while it decreases across a period due to the increase in effective nuclear charge.
B. The atomic radius decreases down a group due to the increase in effective nuclear charge, while it increases across a period due to the addition of new energy levels.
C. The atomic radius remains cons\tant down a group and across a period due to the equal number of protons and electrons.
D. The atomic radius increases down a group and across a period due to the increase in the number of protons.
Question 12
A 2.5 g sample of a polymer is dissolved in 50 mL of a solvent. If the density of the solution is 1.2 g/mL, what is the molarity of the solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 13
A 1.0 M solution of H2SO4 is mixed with 1.0 M solution of NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 14
A solution containing 0.1 M NaCl is electrolyzed u\sing a platinum electrode. If the current is 2 A, what is the mass of Cl2 produced after 10 minutes?
A. 0.1 g
B. 0.2 g
C. 0.3 g
D. 0.4 g
Question 15
A 2.5 g sample of a metal carbonate is heated to produce a metal oxide and carbon dioxide gas. The mass of the metal oxide produced is 1.8 g. What is the percentage yield of the reaction?
A. 72%
B. 80%
C. 88%
D. 96%

Master the Exam!

You've seen a preview, but there are thousands more questions plus AI tutor to break down complex solutions.

Unlock Full Access Available for Android & Windows
Help others prepare! Share this practice hub: