POST UTME BSU 2024 Chemistry | Objective

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Question 1
A 2.5 g sample of a non-metallic oxide is heated in a stream of CO gas. If 1.2 g of CO is consumed, calculate the empirical formula of the oxide.
A. MgO
B. CaO
C. SiO2
D. Al2O3
Question 2
A 1.5 g sample of a colloidal solution is centrifuged at 3000 rpm for 30 minutes. If the superna\tant is 0.5 M in KCl, calculate the mass of the solute particles.
A. 0.1
B. 0.2
C. 0.3
D. 0.4
Question 3
The diagram below shows a titration setup. If the burette contains 0.1 M NaOH and the initial volume is 25 mL, what is the concentration of the HCl solution if 10 mL of NaOH is required to reach the equivalence point?
A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.5 M
Question 4
A 1.0 M solution of a weak base, B, is titrated with 1.0 M HCl. If the initial pH of the base is 10.5, what is the pH at the equivalence point?
A. 3.5
B. 5.5
C. 7.5
D. 9.5
Question 5
A solution of 0.1 M NaCl is prepared by dissolving 6.0 g of NaCl in 100 mL of water. What is the concentration of the solution in g/L?
A. 0.6 g/L
B. 6.0 g/L
C. 60 g/L
D. 600 g/L
Question 6
A metal M reacts with oxygen to form a basic oxide MO. If 2.5 g of M reacts with 1.5 g of O2 to form 3.5 g of MO, what is the percentage of M in MO?
A. 40%
B. 40%
C. 40%
D. 40%
Question 7
A 10 M solution of H2SO4 is mixed with a 1 M solution of NaOH. Calculate the concentration of the resulting solution.
A. \( 5 , \text{M} \)
B. \( 10 , \text{M} \)
C. \( 15 , \text{M} \)
D. \( 20 , \text{M} \)
Question 8
A 2.0 M solution of NH3 is mixed with a 1.0 M solution of HCl. Calculate the pH of the resulting solution.
A. \( \text{pH} = 7 \)
B. \( \text{pH} = 8 \)
C. \( \text{pH} = 9 \)
D. \( \text{pH} = 10 \)
Question 9
A solution of 0.1 M NaCl is prepared by dissolving 6.0 g of NaCl in 100 mL of water. What is the concentration of the solution in g/L?
A. 0.6 g/L
B. 6.0 g/L
C. 60 g/L
D. 600 g/L
Question 10
A 1.0 L sample of a gas at 2.0 atm and 25°C is compressed to 4.0 atm. What is the new volume of the gas?
A. 0.5 L
B. 1.0 L
C. 2.0 L
D. 4.0 L
Question 11
A 25 mL sample of 0.1 M HCl is titrated with 0.1 M NaOH. What is the pH of the solution after the addition of 20 mL of NaOH?
A. 2
B. 7
C. 10
D. 14
Question 12
The half-life of a radioactive subs\tance is 10 years. If 100 g of the subs\tance is initially present, how much of the subs\tance will remain after 20 years?
A. 25 g
B. 50 g
C. 75 g
D. 100 g
Question 13
A 1.0 M solution of a strong acid, HA, is titrated with 1.0 M NaOH. If the initial pH of the acid is 2.5, what is the pH at the equivalence point?
A. 7.5
B. 9.5
C. 11.5
D. 13.5
Question 14
Determine the pH of a 0.1 M solution of HCl at 25°C.
A. 1
B. 2
C. 3
D. 4
Question 15
The rate cons\tant (k) of a second-order reaction is given by the equation: k = 1/t [A]o/[A]t. What is the value of k if the initial concentration of the reac\tant is 0.1 M and the concentration after 10 minutes is 0.01 M?
A. 0.1
B. 0.5
C. 1
D. 2

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