CHEM 115 COMPREHENSIVE EXAM 2026/2027 QUESTIONS
AND SOLUTIONS RATED A+
✔✔Evaporation is:
A) the opposite process as condensation.
B) a cooling process for humans when they sweat.
C) an endothermic process.
D) increased by increasing temperature.
E) all of the above - ✔✔E
✔✔Which statement about surface tension is FALSE?
A) Items with densities lower than water will sink due to surface tension.
B) Molecules on the surface of the liquid have fewer molecules to interact with.
C) Liquids tend to minimize their surface area.
D) Increased intermolecular forces increase surface tension.
E) All of the above statements are true. - ✔✔A
✔✔What are the principal forces holding ice together?
A) electrostatic attraction
B) sea of electrons
C) intermolecular forces
D) dispersion forces only
E) none of the above - ✔✔C
✔✔Which statement about boiling point is FALSE?
A) The boiling point of a compound is an absolute constant.
B) The boiling point is higher for compounds with a high viscosity.
C) The boiling point of a compound is higher for nonvolatile compounds.
D) The boiling point is higher for compounds with strong intermolecular forces.
E) All of the above statements are true - ✔✔A
✔✔How many kJ of heat are needed to completely vaporize 23.4 g of H2O? The heat of
vaporization
for water at the boiling point is 40.6 kJ/mole.
A) 52.8
B) 31.2
C) 23.4
D) 2.26
E) none of the above - ✔✔A
✔✔Which substance would be expected to have the highest boiling point?
A) O2
B) N2
C) CO2
, D) CO
E) not enough information - ✔✔D
✔✔Compare a small pot of water that is boiling vigorously to a large pot of water that is
boiling gently.
Which statement is TRUE?
A) The vapor pressure of the liquid is greater than the pressure above the pot in each
case.
B) The small pot is boiling at higher temperature than the large pot.
C) The large pot is boiling at a higher temperature than the small pot.
D) Both pots are boiling at the same temperature.
E) none of the above - ✔✔D
✔✔How many kJ of heat are needed to completely melt 17.3 g of H2O, given that the
water is at its
melting point? The heat of fusion for water is 6.02 kJ/mole.
A) 0.961
B) 1.04
C) 6.26
D) 5.79
E) none of the above - ✔✔A
✔✔How many joules of heat are needed to completely vaporize 24.40 grams of water at
its boiling
point?
Given ΔHvap = 40.6 kJ/mol
A) 5.50 × 104
B) 3.00 × 104
C) 54.97
D) 29.98
E) none of the above - ✔✔A
✔✔How many kilojoules of heat are needed to completely vaporize 42.8 grams of
C4H10O at its
boiling point?
Given ΔHvap = 26.5kJ/mol
A) 16.3
B) 9.49
C) 74.12
D) 15.3
E) none of the above - ✔✔D
✔✔ When a nonmetal bonds with a nonmetal
A) a molecular compound forms.
B) electrons are shared.
AND SOLUTIONS RATED A+
✔✔Evaporation is:
A) the opposite process as condensation.
B) a cooling process for humans when they sweat.
C) an endothermic process.
D) increased by increasing temperature.
E) all of the above - ✔✔E
✔✔Which statement about surface tension is FALSE?
A) Items with densities lower than water will sink due to surface tension.
B) Molecules on the surface of the liquid have fewer molecules to interact with.
C) Liquids tend to minimize their surface area.
D) Increased intermolecular forces increase surface tension.
E) All of the above statements are true. - ✔✔A
✔✔What are the principal forces holding ice together?
A) electrostatic attraction
B) sea of electrons
C) intermolecular forces
D) dispersion forces only
E) none of the above - ✔✔C
✔✔Which statement about boiling point is FALSE?
A) The boiling point of a compound is an absolute constant.
B) The boiling point is higher for compounds with a high viscosity.
C) The boiling point of a compound is higher for nonvolatile compounds.
D) The boiling point is higher for compounds with strong intermolecular forces.
E) All of the above statements are true - ✔✔A
✔✔How many kJ of heat are needed to completely vaporize 23.4 g of H2O? The heat of
vaporization
for water at the boiling point is 40.6 kJ/mole.
A) 52.8
B) 31.2
C) 23.4
D) 2.26
E) none of the above - ✔✔A
✔✔Which substance would be expected to have the highest boiling point?
A) O2
B) N2
C) CO2
, D) CO
E) not enough information - ✔✔D
✔✔Compare a small pot of water that is boiling vigorously to a large pot of water that is
boiling gently.
Which statement is TRUE?
A) The vapor pressure of the liquid is greater than the pressure above the pot in each
case.
B) The small pot is boiling at higher temperature than the large pot.
C) The large pot is boiling at a higher temperature than the small pot.
D) Both pots are boiling at the same temperature.
E) none of the above - ✔✔D
✔✔How many kJ of heat are needed to completely melt 17.3 g of H2O, given that the
water is at its
melting point? The heat of fusion for water is 6.02 kJ/mole.
A) 0.961
B) 1.04
C) 6.26
D) 5.79
E) none of the above - ✔✔A
✔✔How many joules of heat are needed to completely vaporize 24.40 grams of water at
its boiling
point?
Given ΔHvap = 40.6 kJ/mol
A) 5.50 × 104
B) 3.00 × 104
C) 54.97
D) 29.98
E) none of the above - ✔✔A
✔✔How many kilojoules of heat are needed to completely vaporize 42.8 grams of
C4H10O at its
boiling point?
Given ΔHvap = 26.5kJ/mol
A) 16.3
B) 9.49
C) 74.12
D) 15.3
E) none of the above - ✔✔D
✔✔ When a nonmetal bonds with a nonmetal
A) a molecular compound forms.
B) electrons are shared.
