POST UTME UNN 2018 Chemistry | Objective

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Question 1
A metal (X) reacts with dilute hydrochloric acid to produce a gas (Y). The gas (Y) is used in the manufacture of semiconductors. Identify the metal (X) and the gas (Y).
A. Zinc, Hydrogen
B. Iron, Carbon Dioxide
C. Copper, Oxygen
D. Lead, Nitrogen
Question 2
Determine the pH of a 0.1 M solution of HCl in water at 25°C, given that the dissociation cons\tant of HCl is 10^\( -7 \).
A. 1
B. 2
C. 3
D. 4
Question 3
The graph below shows the relationship between the volume of a gas and its pressure. What is the slope of the graph?
A. 1
B. 2
C. 3
D. 4
Question 4
A sample of air contains 21% oxygen, 78% nitrogen, and 1% other gases. What is the partial pressure of oxygen in the air?
A. 0.21 atm
B. 0.21 kPa
C. 21 kPa
D. 21 atm
Question 5
A 50 mL sample of a 0.1 M solution of NaOH is mixed with 50 mL of a 0.1 M solution of HCl. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 6
A 100.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after the reaction is complete?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 7
The half-life of a radioactive subs\tance is 5 years. If the initial activity is 1000 Bq, what is the activity after 10 years?
A. 100 Bq
B. 500 Bq
C. 1000 Bq
D. 5000 Bq
Question 8
The diagram below shows a circuit. Identify the component labeled A.
A. Resistor
B. Battery
C. Capacitor
D. Inductor
Question 9
The diagram below represents a titration setup. What is the purpose of the burette in this setup?
A. To measure the volume of the solution
B. To measure the concentration of the solution
C. To mix the solutions
D. To separate the solutions
Question 10
Determine the number of unpaired electrons in the ground state of a neutral chromium atom.
A. 0
B. 2
C. 4
D. 6
Question 11
A 25 mL sample of a solution containing 0.5 M NaOH is titrated with 0.5 M HCl. Calculate the volume of HCl required to reach the equivalence point.
A. 12.5 mL
B. 25 mL
C. 37.5 mL
D. 50 mL
Question 12
The reaction of sodium with water is represented by the equation: 2Na + 2H2O → 2NaOH + H2. What is the oxidation state of sodium in the product NaOH?
A. +1
B. +2
C. +3
D. +4
Question 13
A 2.00 M solution of NaOH is mixed with a 1.00 M solution of HCl. What is the resulting concentration of the solution after the reaction is complete?
A. 1.00 M
B. 1.50 M
C. 2.00 M
D. 3.00 M
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 half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is initially present, how much will remain after 10 years?
A. 50 g
B. 25 g
C. 12.5 g
D. 6.25 g

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