POST UTME UNIBEN 2019 Chemistry | Objective

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Question 1
A solution contains 30.0 g of sodium chloride (NaCl) dissolved in 250.0 mL of water. Calculate the molarity of the solution.
A. 0.200 M
B. 0.500 M
C. 1.00 M
D. 2.00 M
Question 2
A sample of 1.0 g of a biomolecule is dissolved in 100 mL of a solvent. Calculate the molar mass of the biomolecule, given that the density of the solution is 1.2 g/mL.
A. \( 500 , \text{g/mol} \)
B. \( 1000 , \text{g/mol} \)
C. \( 1500 , \text{g/mol} \)
D. \( 2000 , \text{g/mol} \)
Question 3
A sample of 1.0 g of a polymer is dissolved in 100 mL of a solvent. Calculate the molar mass of the polymer, given that the density of the solution is 1.2 g/mL.
A. \( 1000 , \text{g/mol} \)
B. \( 2000 , \text{g/mol} \)
C. \( 3000 , \text{g/mol} \)
D. \( 4000 , \text{g/mol} \)
Question 4
A diagram of a titration setup is shown below. If 25.0 mL of 0.100 M NaOH is required to reach the equivalence point, what is the concentration of the HCl solution?
A. 0.100 M
B. 0.100 M
C. 0.100 M
D. 0.100 M
Question 5
A solution contains 25.0 g of glu\cose (C6H12O6) dissolved in 250.0 mL of water. Calculate the molarity of the solution.
A. 0.100 M
B. 0.500 M
C. 1.00 M
D. 2.00 M
Question 6
A 2.50-g sample of a metal oxide is heated in a crucible until it decomposes completely. The mass of the metal obtained is 1.25 g. What is the empirical formula of the oxide?
A. MgO
B. CaO
C. Fe2O3
D. CuO
Question 7
A sample of a metal oxide has a mass of 25.0 g and a volume of 5.00 cm^3. If the density of the oxide is 4.50 g/cm^3, what is the number of moles of oxygen in the sample?
A. 0.111 mol
B. 0.222 mol
C. 0.333 mol
D. 0.444 mol
Question 8
A 1.0 M solution of sodium hydroxide (NaOH) is mixed with a 2.0 M solution of hydrochloric acid (HCl). If 50 mL of the sodium hydroxide solution is added to 100 mL of the hydrochloric acid solution, what is the pH of the resulting solution?
A. 1.0
B. 2.0
C. 3.0
D. 4.0
Question 9
A sample of 1.0 g of a compound containing only carbon and hydrogen is analyzed by combustion. The volume of CO2 produced is 2.5 L at 25°C and 1 atm. What is the empirical formula of the compound?
A. CH
B. C2H2
C. C3H4
D. C4H6
Question 10
A sample of 1.0 g of a compound containing only carbon and oxygen is analyzed by combustion. The volume of CO2 produced is 1.5 L at 25°C and 1 atm. What is the empirical formula of the compound?
A. CO
B. C2O2
C. C3O3
D. C4O4
Question 11
A sample of an organic compound has a molecular formula of C_4H_8O_2. What is the IUPAC name of the compound?
A. Bu\tan-2-ol
B. Bu\tan-1-ol
C. Bu\tan-2-one
D. Bu\tan-1-one
Question 12
A solution of 0.100 M HCl is titrated with 0.100 M NaOH. What is the pH of the solution after 25.0 mL of NaOH has been added?
A. 2.00
B. 3.00
C. 4.00
D. 5.00
Question 13
The reaction between chlorine gas and sodium hydroxide solution is represented by the equation: Cl2 + 2NaOH → NaCl + NaClO + H2O. If 2.5 g of chlorine gas is added to 100 mL of 1 M sodium hydroxide solution, what is the limiting reac\tant?
A. Chlorine gas
B. Sodium hydroxide solution
C. Neither chlorine gas nor sodium hydroxide solution is the limiting reac\tant
D. Both chlorine gas and sodium hydroxide solution are the limiting reac\tants
Question 14
A metal has an atomic radius of 150 pm and an electron affinity of -200 kJ/mol. What is the energy change when an electron is added to the metal?
A. -200 kJ/mol
B. -150 kJ/mol
C. -100 kJ/mol
D. -50 kJ/mol
Question 15
A solution of 0.1 M NaOH is prepared by dissolving 4.0 g of NaOH in 100 mL of water. What is the concentration of OH- ions in the solution?
A. 0.1 M
B. 0.01 M
C. 0.001 M
D. 0.0001 M

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