POST UTME UNIOSUN 2019 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
The reaction between sodium metal and water is represented by the equation: 2Na(s) + 2H2O(l) → 2NaOH(aq) + H2(g). Calculate the number of moles of hydrogen gas produced when 2 g of sodium metal reacts with excess water.
A. 0.025 mol
B. 0.030 mol
C. 0.035 mol
D. 0.040 mol
Question 2
A 0.1 M solution of hydrogen peroxide (H2O2) is prepared by dissolving 1 g of H2O2 in water to make 1 L of solution. Calculate the concentration of the solution in terms of molarity.
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 3
The half-life of a radioactive subs\tance is 5.0 days. If 100 g of the subs\tance initially exists, how much will remain after 20 days?
A. 12.5 g
B. 25.0 g
C. 37.5 g
D. 50.0 g
Question 4
A 0.500 M solution of NaOH is mixed with a 0.500 M solution of HCl. What is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 5
A solution of H2O2 is treated with a strong acid. What is the resulting product?
A. H2O
B. H2SO4
C. HCl
D. HNO3
Question 6
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 1 mol of carbon at 298 K.
A. -393.5 kJ/mol
B. -394.5 kJ/mol
C. -395.5 kJ/mol
D. -396.5 kJ/mol
Question 7
The diagram below shows a chemical apparatus setup. Identify the part labeled A.
A. Burette
B. Beaker
C. Conical flask
D. Test tube
Question 8
The reaction between zinc metal and copper(II) sulfate solution is represented by the equation: Zn(s) + CuSO4(aq) → ZnSO4(aq) + Cu(s). Calculate the number of moles of copper metal deposited when 2.5 g of zinc metal reacts with excess copper(II) sulfate solution. The molar mass of zinc is 65.38 g/mol, and the molar mass of copper is 63.55 g/mol.
A. 0.038 mol
B. 0.039 mol
C. 0.040 mol
D. 0.041 mol
Question 9
A metal reacts with oxygen to form a compound with the formula M2O3. If 25.0 g of the metal is used, what is the mass of oxygen in the compound?
A. 10.0 g
B. 15.0 g
C. 20.0 g
D. 25.0 g
Question 10
The s\tandard enthalpy of formation of CO2(g) is -393.5 kJ/mol. Calculate the s\tandard enthalpy of combustion of 2.5 g of carbon at 298 K.
A. -981.25 kJ
B. -981.375 kJ
C. -981.5 kJ
D. -981.625 kJ
Question 11
A 0.1 M solution of a weak acid HA is titrated with 0.1 M NaOH. If 20 mL of NaOH is required to reach the equivalence point, calculate the number of moles of HA present in 100 mL of the acid solution.
A. 0.0025 mol
B. 0.005 mol
C. 0.0075 mol
D. 0.01 mol
Question 12
A metal, M, has a molar mass of 50.0 g/mol. If 2.00 g of the metal is dissolved in 50.0 mL of 0.100 M HCl, what is the concentration of the metal ion in the resulting solution?
A. 0.100 M
B. 0.200 M
C. 0.300 M
D. 0.400 M
Question 13
A 1.0 M solution of NaOH is mixed with a 1.0 M solution of HCl. What is the resulting pH?
A. 7
B. 10
C. 12
D. 14
Question 14
A solution contains 10.0 g of glu\cose. What is the molarity of the solution, assuming a density of 1.0 g/mL?
A. 0.1 M
B. 0.5 M
C. 1.0 M
D. 2.0 M
Question 15
A 0.1 M solution of AgNO3 is mixed with a 0.1 M solution of NaCl. If the resulting solution is a double salt, what is the molar concentration of the double salt?
A. 0.05 M
B. 0.1 M
C. 0.2 M
D. 0.05 M

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