POST UTME ABU 2019 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A metal has a density of 8.0 g/cm^3 and a molar mass of 60 g/mol. Calculate the number of moles of metal present in a 10 g sample.
A. 0.1 mol
B. 0.2 mol
C. 0.3 mol
D. 0.4 mol
Question 2
What is the primary function of the ha\logen family in the periodic table?
A. To form acids
B. To form bases
C. To form salts
D. To form oxides
Question 3
A 3.00 g sample of a metal oxide is heated in a crucible until it decomposes completely. The mass of the metal obtained is 1.50 g. Calculate the percentage of metal in the original sample.
A. 30.0%
B. 40.0%
C. 50.0%
D. 60.0%
Question 4
The half-life \( t1/2 \) of a radioactive subs\tance is 5.00 years. If the initial amount (N0) is 100 g, calculate the amount (N) remaining after 10.0 years.
A. 12.5 g
B. 12.6 g
C. 12.7 g
D. 12.8 g
Question 5
Determine the rate cons\tant (k) for the first-order reaction: A → B, given that the initial concentration of A is 0.1 M and the concentration of A after 2 hours is 0.05 M. The rate cons\tant is related to the half-life \( t1/2 \) of the reaction by the equation: k = ln(2) / t1/2.
A. 0.693 h^-1
B. 1.386 h^-1
C. 2.772 h^-1
D. 3.464 h^-1
Question 6
The reaction of an alkane with chlorine in the presence of light produces a dichloroalkane. What is the major product of this reaction?
A. 1,2-dichloropropane
B. 1,3-dichloropropane
C. 1,4-dichloropropane
D. 1,5-dichloropen\tane
Question 7
What is the term for the movement of molecules from an area of high concentration to an area of low concentration?
A. Diffusion
B. Osmosis
C. Active transport
D. Passive transport
Question 8
The equilibrium cons\tant (K) for a reaction is given by the equation: K = [A]^2 / [B]. If the concentration of A is 1.0 x 10^\( -3 \) M and the concentration of B is 1.0 x 10^\( -4 \) M, calculate the equilibrium cons\tant (K).
A. 1.0 x 10^3
B. 1.0 x 10^4
C. 1.0 x 10^5
D. 1.0 x 10^6
Question 9
A solution contains 20 g of glu\cose (C6H12O6) per 100 g of water. Calculate the molality of the solution.
A. 0.11
B. 0.22
C. 0.33
D. 0.44
Question 10
Calculate the s\tandard enthalpy change (ΔH°) for the reaction: 2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s). The s\tandard enthalpy of formation (ΔHf°) values are: ΔHf°(Al2O3) = -1675.7 kJ/mol, ΔHf°(Fe) = 0 kJ/mol, ΔHf°(Al) = 0 kJ/mol, ΔHf°(Fe2O3) = -826.4 kJ/mol.
A. -1031.1 kJ/mol
B. -1031.2 kJ/mol
C. -1031.3 kJ/mol
D. -1031.4 kJ/mol
Question 11
In a redox reaction, what is the role of the oxidizing agent?
A. To donate electrons
B. To accept electrons
C. To facilitate the reaction
D. To inhibit the reaction
Question 12
A 2.00 M solution of H2SO4 is mixed with a 2.00 M solution of NaOH. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 13
The rate cons\tant (k) for a first-order reaction is given by the equation: k = Ae^\( -Ea/RT \). If the activation energy (Ea) is 100 kJ/mol, the gas cons\tant (R) is 8.314 J/\( mol*K \), and the temperature (T) is 300 K, calculate the rate cons\tant (k) when the pre-exponential factor (A) is 1.0 x 10^10 s^\( -1 \).
A. 1.0 x 10^\( -5 \) s^\( -1 \)
B. 1.0 x 10^\( -4 \) s^\( -1 \)
C. 1.0 x 10^\( -3 \) s^\( -1 \)
D. 1.0 x 10^\( -2 \) s^\( -1 \)
Question 14
The reaction between hydrogen gas and chlorine gas is highly exothermic. The reaction is represented by the equation: 2H2(g) + Cl2(g) → 2HCl(g). If 2.00 g of H2 is mixed with 3.00 g of Cl2, what is the limiting reac\tant?
A. H2
B. Cl2
C. Both are in excess
D. Neither is in excess
Question 15
A 1.00 g sample of a metal is heated in a crucible until it decomposes completely. The mass of the metal oxide obtained is 1.50 g. What is the percentage of oxygen in the original sample?
A. 20.0%
B. 30.0%
C. 40.0%
D. 50.0%

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