POST UTME LAUTECH 2017 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
A sample of an ideal gas is heated at cons\tant volume. Which of the following statements is true about the change in the gas's properties?
A. The gas expands and its pressure increases.
B. The gas contracts and its pressure decreases.
C. The gas expands and its pressure remains cons\tant.
D. The gas contracts and its pressure increases.
Question 2
The half-life of a radioactive subs\tance is 5.0 years. If 100 g of the subs\tance is initially present, how much will remain after 10 years?
A. 50 g
B. 25 g
C. 12.5 g
D. 6.25 g
Question 3
A solution of sodium hydroxide (NaOH) is prepared by dissolving 25 g of NaOH in 100 mL of water. What is the pH of the solution?
A. 1
B. 2
C. 3
D. 4
Question 4
Determine the molar solubility of AgCl in a solution containing 0.1 M NaCl. The solubility product cons\tant (Ksp) for AgCl is 1.8 x 10^-10.
A. 1.0 x 10^-5 M
B. 1.0 x 10^-6 M
C. 1.0 x 10^-7 M
D. 1.0 x 10^-8 M
Question 5
The atomic radius of an element in the periodic table generally increases down a group due to the addition of new energy levels. However, the atomic radius of an element in the periodic table generally decreases across a period due to the increase in effective nuclear charge. Which of the following elements has the largest atomic radius?
A. Rb
B. Cs
C. Fr
D. Ba
Question 6
Calculate the s\tandard enthalpy change for the reaction: 2Al(s) + Fe2O3(s) → 2Fe(s) + Al2O3(s). Given that ΔH°(Al2O3(s)) = -1675 kJ/mol and ΔH°(Fe(s)) = 0 kJ/mol.
A. -1675 kJ/mol
B. -3350 kJ/mol
C. -1675 kJ/mol
D. -3350 kJ/mol
Question 7
A 0.500 L flask contains 0.100 mol of an ideal gas at 298 K. If the gas is heated to 373 K, what is the new volume of the gas?
A. 0.500 L
B. 0.750 L
C. 1.00 L
D. 1.25 L
Question 8
The reaction of 2.5 g of an unknown organic compound with 100.0 mL of 0.5 M NaOH(aq) produces 1.25 g of a precipitate. If the molar mass of the unknown compound is 56.0 g/mol, what is its empirical formula?
A. C_2H_4O
B. C_2H_6O
C. C_3H_6O
D. C_4H_8O
Question 9
The entropy of a subs\tance is a measure of its disorder or randomness. Which of the following subs\tances has the highest entropy?
A. \( \text{H}_2\text{O}\( \text{l} \ \) )
B. \( \text{CO}_2\( \text{g} \ \) )
C. \( \text{NH}_3\( \text{g} \ \) )
D. \( \text{O}_2\( \text{g} \ \) )
Question 10
A 2.0 L solution contains 0.2 M H2SO4. What is the concentration of H+ ions in the solution?
A. 0.1 M
B. 0.2 M
C. 0.4 M
D. 0.8 M
Question 11
The boiling point of a solution containing 10.0 g of glu\cose (C6H12O6) in 100.0 g of water is 100.5°C. Calculate the molar mass of glu\cose.
A. 180 g/mol
B. 200 g/mol
C. 220 g/mol
D. 240 g/mol
Question 12
A metal rod is heated to a temperature of 800°C and then quenched in water. What is the change in entropy of the rod?
A. increase
B. decrease
C. no change
D. dep\endent on the type of metal
Question 13
A mixture of 10 g of glu\cose (C6H12O6) and 20 g of fructose (C6H12O6) is dissolved in 100 mL of water. What is the osmotic pressure of the solution?
A. 10 atm
B. 20 atm
C. 30 atm
D. 40 atm
Question 14
A 1.0 L solution contains 0.5 M NaOH. What is the concentration of OH- ions in the solution?
A. 0.5 M
B. 0.25 M
C. 0.1 M
D. 0.05 M
Question 15
A 2.00 L flask contains 0.200 mol of an ideal gas at 298 K. If the gas is compressed to 1.00 L, what is the new pressure of the gas?
A. 2.02 atm
B. 4.04 atm
C. 6.06 atm
D. 8.08 atm

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