POST UTME UNN 2017 Chemistry | Objective

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Question 1
A 1 L solution of 0.5 M HCl is prepared by dissolving 250 g of HCl in water. What is the mass of HCl in the solution?
A. 125 g
B. 250 g
C. 375 g
D. 500 g
Question 2
A solution of 2 M HCl is titrated with 1 M NaOH. If 25 mL of NaOH is added, what is the pH of the resulting solution?
A. 2
B. 3
C. 4
D. 5
Question 3
The rate cons\tant (k) for a first-order reaction is given by the equation \( k = Ae^{-E_a/RT} \). If the activation energy \( E_a \) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/mol*K, and the temperature (T) is 298 K, what is the value of A?
A. 1.0 x 10^10
B. 1.0 x 10^5
C. 1.0 x 10^2
D. 1.0 x 10^-5
Question 4
The half-life \( t_1/2 \) of a radioactive subs\tance is given by the equation \( t_{1/2} = \frac{ln 2}{k} \). If the decay cons\tant (k) is 0.05 min^-1, what is the half-life of the subs\tance?
A. 14 min
B. 28 min
C. 42 min
D. 56 min
Question 5
A 0.1 M solution of NaOH is prepared by dissolving 4 g of NaOH in water and diluting to 1 L. What is the molarity of the resulting solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of CO(g)?
A. 117.2 kJ/mol
B. -117.2 kJ/mol
C. 117.2 kJ/mol
D. -393.5 kJ/mol
Question 7
The s\tandard enthalpy of formation of H2O(l) is -285.8 kJ/mol. What is the s\tandard enthalpy of formation of H(g)?
A. 0 kJ/mol
B. 285.8 kJ/mol
C. -285.8 kJ/mol
D. 117.2 kJ/mol
Question 8
The s\tandard enthalpy of formation of CH4(g) is -74.8 kJ/mol. What is the s\tandard enthalpy of formation of C(s)?
A. 0 kJ/mol
B. 74.8 kJ/mol
C. -74.8 kJ/mol
D. 117.2 kJ/mol
Question 9
A 0.05 M solution of H2SO4 is titrated with 0.05 M NaOH. If 50 mL of NaOH is required to reach the equivalence point, what is the volume of H2SO4 used?
A. 50 mL
B. 75 mL
C. 100 mL
D. 125 mL
Question 10
A diagram of a chemical apparatus is shown below. If 25.0 mL of 0.100 M sodium hydroxide (NaOH) is used to titrate 25.0 mL of 0.100 M hydrochloric acid (HCl), what is the resulting concentration of sodium chloride (NaCl) in the solution?
A. 0.500 M
B. 0.750 M
C. 1.000 M
D. 1.250 M
Question 11
A 0.1 M solution of HCl is titrated with 0.1 M NaOH. If 25 mL of NaOH is required to reach the equivalence point, what is the volume of HCl used?
A. 25 mL
B. 50 mL
C. 75 mL
D. 100 mL
Question 12
A 2 L solution of 0.2 M NaOH is prepared by dissolving 40 g of NaOH in water. What is the molarity of the resulting solution?
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 13
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. What is the s\tandard enthalpy of formation of O2(g)?
A. 0 kJ/mol
B. 393.5 kJ/mol
C. -393.5 kJ/mol
D. 117.2 kJ/mol
Question 14
A sample of a gas at 27°C and 1 atm is heated to 127°C at cons\tant pressure. What is the new volume of the gas, given that the initial volume is 2.5 L?
A. 6.5 L
B. 8.5 L
C. 10.5 L
D. 12.5 L
Question 15
A 1.00 M solution of sodium hydroxide (NaOH) is titrated with a 1.00 M solution of hydrochloric acid (HCl). If 25.0 mL of NaOH is titrated with 25.0 mL of HCl, what is the pH of the resulting solution?
A. 7.00
B. 7.50
C. 8.00
D. 8.50

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