POST UTME EKSU 2017 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A 2.50 M solution of HCl is mixed with a 1.00 M solution of NaOH. Calculate the pH of the resulting solution.
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 2
A sample of air contains 20% oxygen, 70% nitrogen, and 10% carbon dioxide by volume. If the total volume of the air sample is 1000 cm^3, calculate the volume of oxygen present in the sample.
A. 100 cm^3
B. 200 cm^3
C. 300 cm^3
D. 400 cm^3
Question 3
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. Calculate the pH of the solution after the addition of 25.0 mL of NaOH.
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 4
A 2.0 M solution of ammonia (NH3) is titrated with a 1.0 M solution of hydrochloric acid (HCl). If 20 cm^3 of the acid is required to reach the equivalence point, calculate the number of moles of NH3 present in 100 cm^3 of the solution.
A. 0.01 moles
B. 0.02 moles
C. 0.03 moles
D. 0.04 moles
Question 5
The atomic radius of an element increases down a group in the periodic table. Explain why this is the case.
A. Due to the increase in the number of energy levels
B. Due to the decrease in the effective nuclear charge
C. Due to the increase in the atomic mass
D. Due to the decrease in the atomic number
Question 6
The diagram below shows a simple black and white chemistry apparatus showing a titration setup. Identify the part labeled A.
A. The burette
B. The beaker
C. The pipette
D. The flask
Question 7
A 1.00 M solution of HCl is mixed with a 1.00 M solution of NaOH. Calculate the number of moles of HCl that react with NaOH.
A. 1.00 mol
B. 2.00 mol
C. 3.00 mol
D. 4.00 mol
Question 8
The solubility of a gas in a liquid is given by the equation: \( S = \frac{P}{k} \), where S is the solubility, P is the partial pressure of the gas, and k is a cons\tant. If the partial pressure of a gas is 2 atm and the cons\tant k is 0.5 atm, what is the solubility of the gas in the liquid?
A. 4 atm
B. 2 atm
C. 1 atm
D. 0.5 atm
Question 9
A 1.5 M solution of H2SO4 is prepared by dissolving 49 g of H2SO4 in 1000 mL of water. What is the concentration of H+ ions in the solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 10
A sample of a non-metallic element has a mass of 25.0 g and a volume of 5.00 mL. If the density of the element is 3.00 g/mL, what is the expected boiling point of the element?
A. 100°C
B. 200°C
C. 300°C
D. 400°C
Question 11
A 2.0 M solution of NaOH is prepared by dissolving 40 g of NaOH in 1000 mL of water. What is the concentration of OH- ions in the solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 12
The diagram below shows a titration setup. Identify the part labeled A.
A. The burette
B. The beaker
C. The pipette
D. The flask
Question 13
A 1.0 M solution of HCl is prepared by dissolving 36.5 g of HCl in 1000 mL of water. What is the concentration of H+ ions in the solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 14
The half-life of a radioactive subs\tance is 5.0 days. If 100 mg of the subs\tance is present initially, how much will remain after 15 days?
A. 12.5 mg
B. 25.0 mg
C. 50.0 mg
D. 100 mg
Question 15
A 2.50 g sample of a non-metallic element is heated in a crucible until it reaches a temperature of 2500°C. If the element has a molar mass of 40.0 g/mol, what is the number of moles of the element present?
A. 0.0625 mol
B. 0.125 mol
C. 0.250 mol
D. 0.500 mol

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