POST UTME MOUNTAIN TOP UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The atomic radius of an element increases down a group in the periodic table due to the addition of new energy levels. However, the atomic radius of an element decreases across a period due to the increase in effective nuclear charge. Which of the following elements has the largest atomic radius?
A. Rb
B. Cs
C. Fr
D. Ba
Question 2
A gas at 300 K and 1 atm expands to occupy a volume of 2 L. What is the new pressure?
A. 0.5 atm
B. 1 atm
C. 1.5 atm
D. 2 atm
Question 3
The diagram below shows a chemical apparatus setup. What is the purpose of the condenser?
A. To cool the gas
B. To heat the gas
C. To mix the gas and liquid
D. To measure the pressure of the gas
Question 4
The half-life of a radioactive subs\tance is 5 years. If the initial activity is 1000 Bq, calculate the activity after 10 years.
A. 125 Bq
B. 250 Bq
C. 500 Bq
D. 1000 Bq
Question 5
A 1.0 M solution of acetic acid (CH3COOH) is titrated with a 1.0 M solution of sodium hydroxide (NaOH). If 20 mL of NaOH is required to reach the equivalence point, what is the pH of the solution at the equivalence point?
A. 7
B. 8
C. 9
D. 10
Question 6
A diagram of a simple black and white chemistry apparatus showing a titration setup is shown below.
A. The burette contains the acid.
B. The beaker contains the acid.
C. The burette contains the base.
D. The beaker contains the base.
Question 7
The s\tandard electrode potential of a metal is a measure of its t\endency to lose electrons. Which of the following metals has the highest s\tandard electrode potential?
A. Li
B. Na
C. K
D. Ca
Question 8
The s\tandard enthalpy of formation \( ΔH^circ_f \) of CO_2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of formation of H_2O(l) if the s\tandard enthalpy of formation of H_2(g) is 0 kJ/mol and the s\tandard enthalpy of formation of O_2(g) is 0 kJ/mol.
A. -285.8 kJ/mol
B. -285.8 kJ/mol
C. -285.8 kJ/mol
D. -285.8 kJ/mol
Question 9
A 2.5 M solution of sodium hydroxide (NaOH) is mixed with a 1.8 M solution of hydrochloric acid (HCl). What is the resulting concentration of the sodium chloride (NaCl) solution?
A. 1.65 M
B. 2.15 M
C. 2.65 M
D. 3.15 M
Question 10
A solution of HCl is titrated with a solution of NaOH. If 25 cm3 of the HCl solution requires 35 cm3 of the NaOH solution for neutralization, calculate the concentration of the HCl solution.
A. 0.1 M
B. 0.2 M
C. 0.5 M
D. 1 M
Question 11
In a reaction between hydrochloric acid and sodium hydroxide, the products are water and sodium chloride. What is the type of reaction?
A. Endothermic reaction
B. Exothermic reaction
C. Neutralization reaction
D. Oxidation reaction
Question 12
A sample of a gas at 25°C and 1.00 atm is compressed to 2.00 atm. What is the new temperature?
A. 37.5°C
B. 50.0°C
C. 62.5°C
D. 75.0°C
Question 13
The reaction of hydrogen gas with oxygen gas is a classic example of a combustion reaction. Write the balanced chemical equation for this reaction.
A. 2H2 + O2 → 2H2O
B. H2 + O2 → H2O
C. 2H2 + O2 → H2O2
D. H2 + O2 → H2O2
Question 14
In a redox reaction, the oxidation state of the metal ion in the reac\tant is +2, and it is reduced to a metal with an oxidation state of 0. If the reaction is carried out in a solution with a pH of 7, what is the s\tandard electrode potential (E°) of the metal?
A. 0.5 V
B. -0.5 V
C. 1.0 V
D. -1.0 V
Question 15
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. -110.5 kJ/mol
B. -137.3 kJ/mol
C. -393.5 kJ/mol
D. -74.8 kJ/mol

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