POST UTME LASU 2018 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The reaction: 2A + B → C + D is a first-order reaction with respect to A. If the initial concentration of A is 0.1 M and the rate cons\tant is 0.05 min^-1, what is the concentration of A after 10 minutes?
A. 0.05 M
B. 0.1 M
C. 0.15 M
D. 0.2 M
Question 2
The reaction 2SO2(g) + O2(g) → 2SO3(g) has a s\tandard enthalpy change of -198 kJ/mol. If 2.5 mol of SO2 and 1.5 mol of O2 are mixed, calculate the total enthalpy change.
A. -495 kJ
B. -520 kJ
C. -545 kJ
D. -570 kJ
Question 3
The diagram below shows the structure of a compound. What is the name of the compound?
A. Ethanol
B. Propanol
C. Bu\tanol
D. Pen\tanol
Question 4
A 2.5 L solution contains 0.5 M H2SO4. Calculate the number of moles of H2O2.
A. 0.5 moles
B. 1 mole
C. 1.5 moles
D. 2 moles
Question 5
A 2.50-g sample of a metal M is heated in air to produce a 3.25-g sample of M2O3. What is the empirical formula of M2O3?
A. M2O3
B. MO2
C. MO3
D. M2O5
Question 6
A 10.0 g sample of a metal oxide is heated in a crucible until it decomposes completely. If 5.0 g of the metal is obtained, what is the empirical formula of the oxide?
A. MgO
B. CaO
C. Fe2O3
D. CuO
Question 7
A 2.5 M solution of HCl is mixed with a 1.5 M solution of NaOH. Calculate the concentration of the resulting solution after the reaction is complete.
A. 1.5 M
B. 2.5 M
C. 3.0 M
D. 4.0 M
Question 8
A metal M reacts with chlorine gas to form a white solid MX. If 2.50 g of M reacts with 1.50 g of Cl2 to produce 3.25 g of MX, what is the empirical formula of MX?
A. MCl2
B. MCl3
C. MCl4
D. MCl5
Question 9
The rate cons\tant (k) of a first-order reaction is 0.05 min^-1. If the initial concentration of the reac\tant is 0.1 M, what is the concentration of the reac\tant after 10 minutes?
A. 0.01 M
B. 0.05 M
C. 0.1 M
D. 0.2 M
Question 10
A 2.0 M solution of NaOH is mixed with a 1.0 M solution of HCl. Calculate the pH of the resulting solution.
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 11
A 2.50 g sample of a polymer is dissolved in 100 mL of a solvent. If the concentration of the solution is 0.050 M, what is the molar mass of the polymer?
A. 500 g/mol
B. 1000 g/mol
C. 2000 g/mol
D. 5000 g/mol
Question 12
The compound C6H14 is a saturated hydrocarbon. What is the name of the compound?
A. hexane
B. hep\tane
C. oc\tane
D. nonane
Question 13
A solution of 0.1 M HCl is mixed with a solution of 0.1 M NaOH. What is the pH of the resulting solution?
A. 1
B. 2
C. 3
D. 4
Question 14
The half-life of a radioactive subs\tance is 5 years. If 100 g of the subs\tance is present initially, how much will be left after 15 years?
A. 25 g
B. 50 g
C. 75 g
D. 100 g
Question 15
A 2.5 L solution contains 0.5 M H2SO4. Calculate the number of moles of H2O.
A. 0.5 moles
B. 1 mole
C. 1.5 moles
D. 2 moles

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