CHEMISTRY B SEMESTER EXAM
QUESTIONS AND ANSWERS GRADED
A+
l Use the periodic table and example bond table to answer the question.
Example Bond Energies of Ionic Compounds Li-F = 1036 kJ/mol Li-Br = 807 kJ/mol Na-F= 923 kJ/mol Na-
Br = 747 kJ/mol
Given the general trend with bond energies, which of the compounds would have the smallest bond
energy? - Cs-Br
Based on the differences in electronegativities, with which atom is francium (Fr) most likely to form an
ionic bond? - Fr-Cl = 2.46
Which statement is the best description of the energy found in molecules of water? - Hotter molecules
have more kinetic energy.
When potassium permanganate and glycerol react, the potential energy of the products is less than the
potential energy of the reactants. Which statement about this reaction is correct? - The reaction is
exothermic.
Hydrochloric acid and sodium hydroxide react to produce water and sodium chloride in an endothermic
reaction. Which statement must be true of the reaction? - More bond energy is absorbed on the
reactants side than is released on the products side.
Imagine a graph. The x-axis is labeled "Time" and is measured in seconds, and the y-axis is labeled
"Potential Energy" and is measured in kilojoules. The slope starts at 0 seconds with a plateau at 25 kJ.
This plateau is labeled "Reactants." The slope then rises to a peak labeled "Activation Energy" at 78 kJ.
Finally the slope drops to a plateau at 14 kJ and is labeled "Products."
What does the graph described above represent? - an exothermic reaction
QUESTIONS AND ANSWERS GRADED
A+
l Use the periodic table and example bond table to answer the question.
Example Bond Energies of Ionic Compounds Li-F = 1036 kJ/mol Li-Br = 807 kJ/mol Na-F= 923 kJ/mol Na-
Br = 747 kJ/mol
Given the general trend with bond energies, which of the compounds would have the smallest bond
energy? - Cs-Br
Based on the differences in electronegativities, with which atom is francium (Fr) most likely to form an
ionic bond? - Fr-Cl = 2.46
Which statement is the best description of the energy found in molecules of water? - Hotter molecules
have more kinetic energy.
When potassium permanganate and glycerol react, the potential energy of the products is less than the
potential energy of the reactants. Which statement about this reaction is correct? - The reaction is
exothermic.
Hydrochloric acid and sodium hydroxide react to produce water and sodium chloride in an endothermic
reaction. Which statement must be true of the reaction? - More bond energy is absorbed on the
reactants side than is released on the products side.
Imagine a graph. The x-axis is labeled "Time" and is measured in seconds, and the y-axis is labeled
"Potential Energy" and is measured in kilojoules. The slope starts at 0 seconds with a plateau at 25 kJ.
This plateau is labeled "Reactants." The slope then rises to a peak labeled "Activation Energy" at 78 kJ.
Finally the slope drops to a plateau at 14 kJ and is labeled "Products."
What does the graph described above represent? - an exothermic reaction
