1) What is true concerning the size of a molecule of a substance?
(a) A molecule is smallest when the substance is solidified.
(b) A molecule is smallest when the substance is vaporized.
(c) A molecule is largest when the substance is liquified.
(d) The size of a molecule is not appreciably affected by phase changes.
2) What happens when 1.0 g of ice melts?
(a) The potential energy of the molecules remains constant.
(b) The kinetic energy of the molecules increases.
(c) The molecules move closer together.
(d) The reaction is exothermic.
3) What is thermal energy?
(a) Thermal energy is the same as the temperature of a substance measured in kelvins.
(b) Thermal energy is the total kinetic and potential energy of the molecules, ions, atoms, and subatomic particles making up a system.
(c) Thermal energy measures only the total kinetic energy of the molecules, ions, atoms, and subatomic particles making up a system.
(d) Thermal energy is not heat energy.
4) Which of the following are the most important factors in determining the boiling temperature of a liquid?
(a) The volume of the liquid and the amount of heat supplied in kJ.
(b) The vapor pressure of the liquid and the atmospheric pressure.
(c) The kinetic and potential energies of the molecules of the liquid.
(d) The nature of the liquid and the shape of its container.
5) Because the collapsing crystal structure is more predominant than the increased molecular motion, the density of water
(a) increases as its temperature is increased from 0°C to 4°C.
(b) increases as its temperature is increased from 0°C to 30°C.
(c) decreases as its temperature is increased from 0°C to 100°C.
(d) decreases as its temperature is increased from 30°C to 80°C.
6) 100. g of water is placed in a closed 150 mL-erlenmeyer flask. When the system reaches equilibrium
(a) the water stops evaporating.
(b) the air in the erlenmeyer flask can hold more water vapor.
(c) the pressure of the water vapor molecules is the equilibrium pressure.
(d) evaporation occurs more rapidly than condensation.
7) When a liquid is boiling
(a) its temperature remains constant.
(b) the kinetic energy of the liquid's molecules continue to increase.
(c) a dissolved solid such as sodium chloride will lower the boiling point.
(d) a dissolved gas such as carbon dioxide will increase the boiling point.
8) The melting point of ice
(a) can be increased by increasing the the pressure.
(b) can be decreased by increasing the the pressure.
(c) differs from the freezing point of water.
(d) is independent of the applied pressure.
9) The concave meniscus of water in a graduated cylinder results because the
(a) adhesion between the water molecules and glass molecules is greater than the cohesion between water molecules.
(b) adhesion between water molecules and the glass exists.
(c) cohesion between the glass molecules exists.
(d) cohesion between the water molecules exists.
10) When water boils under reduced pressure its
(a) ΔHvap = 40.7 kJ/mol.
(b) temperature is 100.°C.
(c) ΔHvap > 40.7 kJ/mol.
(d) boiling point is higher than 100.°C.
11) Which of the following is correct about capillary action?
(a) The liquid elevation is directly proportional to the diameter of the tube.
(b) The liquid elevation is independent of the surface tension of the liquid.
(c) Liquids are depressed in tubes they wet.
(d) The liquid depression decreases as the temperature increases.
12) What results as one molecule approaches another?
(a) The force of attraction increases.
(b) The force of attraction increases, then decreases to zero, and then becomes an increasing force of repulsion.
(c) The force of repulsion increases.
(d) The force of repulsion increases, then decreases to zero, and then becomes an increasing force of attraction.