POST UTME RHEMA UNIVERSITY 2017 Chemistry | Objective

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Question 1
A 2.0 M solution of HCl is mixed with a 2.0 M solution of NaOH. If the reaction is allowed to go to completion, what is the concentration of the resulting solution?
A. 1.0 M HCl
B. 1.0 M NaOH
C. 2.0 M HCl
D. 2.0 M NaOH
Question 2
A 2.5 g sample of a metal oxide is heated in a stream of hydrogen gas. The reaction is as follows: 2MgO(s) + 4H2(g) → 2Mg(s) + 2H2O(l). If the volume of hydrogen gas consumed is 2.5 L at 25°C and 1 atm, what is the molar mass of the metal oxide?
A. 100 g/mol
B. 150 g/mol
C. 200 g/mol
D. 250 g/mol
Question 3
The rate cons\tant for the reaction 2NO(g) + O2(g) → 2NO2(g) is 0.05 s^-1 at 298 K. Calculate the rate cons\tant at 323 K, given that the activation energy is 80 kJ/mol.
A. 0.08 s^-1
B. 0.10 s^-1
C. 0.12 s^-1
D. 0.15 s^-1
Question 4
A 25.0 mL sample of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after the titration is complete?
A. ( 7.00 )
B. ( 10.00 )
C. ( 12.00 )
D. ( 14.00 )
Question 5
A 1.0 M solution of H2SO4 is mixed with a 1.0 M solution of NaOH. If the reaction is allowed to go to completion, what is the concentration of the resulting solution?
A. 1.0 M H2SO4
B. 1.0 M NaOH
C. 2.0 M H2SO4
D. 2.0 M NaOH
Question 6
A metal alloy is composed of 80% copper and 20% zinc. What is the empirical formula of the alloy?
A. Cu2Zn
B. CuZn
C. Cu3Zn2
D. CuZn2
Question 7
A 1.0 M solution of NaOH is mixed with a 1.0 M solution of HCl. Calculate the number of moles of NaCl formed.
A. 0.5 mol
B. 1.0 mol
C. 1.5 mol
D. 2.0 mol
Question 8
A sample of an ideal gas is heated at cons\tant volume. Which of the following statements is true about the change in entropy?
A. Entropy increases
B. Entropy decreases
C. Entropy remains cons\tant
D. Entropy is undefined
Question 9
A gas is collected over water at a temperature of 25°C and a pressure of 1 atm. What is the partial pressure of the gas?
A. 0.9 atm
B. 0.95 atm
C. 1.0 atm
D. 1.05 atm
Question 10
A 0.1 M solution of a weak base, B, is titrated with 0.1 M HCl. If 25 mL of HCl is required to reach the equivalence point, what is the number of moles of B in 1 L of the solution?
A. 0.005 mol
B. 0.01 mol
C. 0.015 mol
D. 0.02 mol
Question 11
A solution containing 0.1 M glu\cose (C6H12O6) and 0.1 M fructose (C6H12O6) is prepared. If 10 mL of this solution is titrated with 0.1 M NaOH, what is the pH of the solution after the titration?
A. 7
B. 8
C. 9
D. 10
Question 12
The reaction of sulfur with oxygen produces sulfur trioxide. Write the balanced equation for this reaction.
A. \( S + O_2 \rightarrow SO_3 \)
B. \( S + O_2 \rightarrow SO_2 \)
C. \( S + O_2 \rightarrow SO_4 \)
D. \( S + O_2 \rightarrow SO_3 + O_2 \)
Question 13
A 1.0 M solution of H2SO4 is mixed with a 1.0 M solution of Ba(OH)2. Calculate the pH of the resulting solution.
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 14
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 2.5 g of carbon at 298 K.
A. -987.5 kJ
B. -393.5 kJ
C. 393.5 kJ
D. 987.5 kJ
Question 15
A sample of 1.0 g of a polymer is dissolved in 100 mL of a solvent. The solution is then titrated with a 0.1 M NaOH solution until the equivalence point is reached. If the volume of NaOH required to reach the equivalence point is 20 mL, what is the molar mass of the polymer?
A. 100 g/mol
B. 200 g/mol
C. 500 g/mol
D. 1000 g/mol

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