POST UTME KSU 2018 Chemistry | Objective

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Question 1
A diagram of the atomic structure of an atom is shown below. What is the name of the region around the nucleus where electrons are most likely to be found?
A. Nucleus
B. Electron Cloud
C. Protons
D. Neutrons
Question 2
A 0.500 L flask contains 0.250 mol of an ideal gas at 298 K. Calculate the number of moles of gas in a 1.00 L flask at 298 K.
A. 0.125 mol
B. 0.250 mol
C. 0.375 mol
D. 0.500 mol
Question 3
A diagram of a titration setup is shown below. What is the purpose of the burette?
A. To measure the volume of the solution
B. To measure the pH of the solution
C. To measure the temperature of the solution
D. To measure the density of the solution
Question 4
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. -110.5 kJ/mol
B. -393.5 kJ/mol
C. -74.8 kJ/mol
D. -283.5 kJ/mol
Question 5
A sample of glu\cose (C6H12O6) has a mass of 25.0 g. What is the number of moles of glu\cose?
A. 0.25 mol
B. 0.50 mol
C. 0.75 mol
D. 1.00 mol
Question 6
A metal M has a density of 10.5 g/cm³ and a molar mass of 65.38 g/mol. Determine the number of moles of M present in 25.0 g of the metal.
A. 0.384 mol
B. 0.385 mol
C. 0.386 mol
D. 0.387 mol
Question 7
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, what is the value of the rate cons\tant (k) if the pre-exponential factor (A) is 1.0 x 10^10 s^-1?
A. 1.0 x 10^6 s^-1
B. 1.0 x 10^7 s^-1
C. 1.0 x 10^8 s^-1
D. 1.0 x 10^9 s^-1
Question 8
A 2.50 M solution of HCl is mixed with a 1.00 M solution of NaOH. Calculate the pH of the resulting solution.
A. 2.00
B. 2.50
C. 3.00
D. 3.50
Question 9
A solution contains 50.0 mL of 0.10 M sodium hydroxide (NaOH) and 50.0 mL of 0.20 M hydrochloric acid (HCl). What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 10
A solution of sulfuric acid (H2SO4) has a concentration of 1 M. If 10 mL of this solution is added to 100 mL of distilled water, what is the new concentration of the solution?
A. 0.1 M
B. 0.5 M
C. 1 M
D. 2 M
Question 11
Determine the s\tandard enthalpy of formation of CaCO3(s) from the following data: ΔHf(CaO(s)) = -635.09 kJ/mol, ΔHf(CO2(g)) = -393.51 kJ/mol. Assume the reaction is: CaO(s) + CO2(g) → CaCO3(s).
A. -1207.6 kJ/mol
B. -1208.6 kJ/mol
C. -1209.6 kJ/mol
D. -1210.6 kJ/mol
Question 12
A solution contains 0.100 M NaCl. What is the concentration of Cl- ions in the solution?
A. 0.050 M
B. 0.100 M
C. 0.150 M
D. 0.200 M
Question 13
A sample of a non-metallic element has a mass of 2.5 g and a volume of 5 mL. If the density of the element is 2.5 g/mL, what is the percentage composition of the element?
A. 50%
B. 60%
C. 70%
D. 80%
Question 14
Determine the number of moles of oxygen gas (O2) that will react with 2.5 moles of methane gas (CH4) according to the balanced equation: CH4 + 2O2 → CO2 + 2H2O.
A. 1.25 moles
B. 2.5 moles
C. 5 moles
D. 10 moles
Question 15
A 2.5 L flask contains 0.5 mol of an ideal gas at 300 K. Calculate the work done when the gas expands to 5 L at cons\tant temperature.
A. -150 J
B. -300 J
C. -450 J
D. -600 J

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