POST UTME CRAWFORD UNIVERSITY 2020 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A metal (M) reacts with oxygen to form a basic oxide. If the reaction is: 4M + 3O2 → 2M2O3, what is the oxidation state of M in the product?
A. +3
B. +2
C. +1
D. -1
Question 2
A solution of 2 M NaOH is mixed with a solution of 1 M HCl. Calculate the pH of the resulting solution.
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 3
A 1.0 M solution of HCl is titrated with 1.0 M NaOH. Calculate the pH of the solution after 20 mL of NaOH has been added.
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 4
The reaction of sodium with water to form sodium hydroxide and hydrogen gas is represented by the equation: \( 2Na + 2H_2O \rightarrow 2NaOH + H_2 \). If 10 g of sodium is allowed to react with excess water, what is the mass of hydrogen gas produced?
A. 2.0 g
B. 4.0 g
C. 6.0 g
D. 8.0 g
Question 5
The reaction of aluminum with copper(II) sulfate to form aluminum sulfate and copper is represented by the equation: \( 2Al + 3CuSO_4 \rightarrow Al_2\( SO_4 \ \)_3 + 3Cu ). If 25 g of aluminum is allowed to react with excess copper(II) sulfate, what is the mass of copper produced?
A. 50 g
B. 75 g
C. 100 g
D. 125 g
Question 6
A 2.0 M solution of HCl is prepared by dissolving 40 g of HCl in 100 mL of water. What is the pH of the solution?
A. 0
B. 1
C. 2
D. 3
Question 7
A diagram of a titration setup is shown below. If the burette contains 0.1 M NaOH and the flask contains 20 mL of 0.1 M HCl, what is the pH of the solution after 10 mL of NaOH has been added?
A. 1
B. 2
C. 3
D. 4
Question 8
A 1.0 M solution of hydrochloric acid is mixed with a 1.5 M solution of sodium hydroxide. If 50 mL of each solution is used, what is the concentration of the resulting solution?
A. 0.75 M
B. 1.0 M
C. 1.25 M
D. 1.5 M
Question 9
A metal oxide has the formula M2O3. If the molar mass of the metal is 50 g/mol and the molar mass of oxygen is 16 g/mol, calculate the mass of the metal oxide in grams per mole.
A. 196 g/mol
B. 198 g/mol
C. 200 g/mol
D. 202 g/mol
Question 10
A sample of a gas at 25°C and 1 atm is found to have a volume of 2.5 L. Calculate the number of moles of the gas present.
A. 0.05 mol
B. 0.10 mol
C. 0.15 mol
D. 0.20 mol
Question 11
A 1.0 M solution of NaOH is prepared by dissolving 40 g of NaOH in 100 mL of water. What is the concentration of OH^- ions in the solution?
A. 0.1 M
B. 0.5 M
C. 1.0 M
D. 2.0 M
Question 12
The graph below represents the relationship between temperature and the volume of a gas at cons\tant pressure.
A. Charles' Law
B. Gay-Lussac's Law
C. Avogadro's Law
D. Boyle's Law
Question 13
A sample of 1.0 g of a metal is heated to 1000°C. If the specific heat capacity of the metal is 0.1 J/g°C, calculate the energy required to heat the metal.
A. 100 J
B. 200 J
C. 300 J
D. 400 J
Question 14
A 0.1 M solution of NaOH is titrated with 0.1 M HCl. If 20 mL of HCl is added, what is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 15
A diagram of a titration setup is shown below. If the burette contains 0.1 M HCl and the flask contains 20 mL of 0.1 M NaOH, what is the pH of the solution after 10 mL of HCl has been added?
A. 1
B. 2
C. 3
D. 4

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