Section Review. Objectives. ⢠Identify factors that determine physical properties of a liquid. ⢠Define evaporation in terms of kinetic energy. â...
Identify factors that determine physical properties of a liquid Define evaporation in terms of kinetic energy Describe the equilibrium between a liquid and its vapor Identify the conditions under which boiling occurs
Part A Completion Use this completion exercise to check your understanding of the concepts and terms that are introduced in this section. Each blank can be completed with a term, short phrase, or number. 1
changes to a gas, the process is called evaporation. A
4.
liquid evaporates faster when heated; however, evaporation itself 5
is a
5.
process. When a partially filled container of liquid is 6
sealed, some of the particles at the
6.
of the liquid vaporize.
7.
These particles collide with the walls of the container, producing a force called
7
. The vapor pressure of a liquid can be
determined by a device called a 9
8.
8
9.
. A liquid boils when its
10.
equals the external pressure. The normal boiling point of a
liquid is the temperature at which the vapor pressure is equal to
10
.
Part B True-False Classify each of these statements as always true, AT; sometimes true, ST; or never true, NT. ________ 11. Particles in a liquid don’t have enough kinetic energy to overcome the attractive forces between them and vaporize. Chapter 13 States of Matter
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Name ___________________________
Date ___________________
Class __________________
________ 12. When a liquid is in a closed container, there are more particles evaporating than condensing. ________ 13. The change of a substance directly from a solid to a gas or vapor is called condensation. ________ 14. The rates of evaporation and condensation are equal at equilibrium. ________ 15. Heating a liquid will increase the temperature of the liquid. ________ 16. During evaporation in an open container, the temperature of a liquid decreases.
Part C Matching Match each description in Column B to the correct term in Column A.
Column A
Column B
________ 17. vapor pressure
a. a measure of the pressure exerted by a gas above a liquid
________ 18. condensation
b. the forces between molecules
________ 19. normal boiling point
c. the boiling point of a liquid at a pressure of 101.3 kPa
________ 20. liquid
d. a fluid with a fixed volume
________ 21. intermolecular attractions
e. the change of a gas or vapor directly to a liquid
Answer the following in the space provided. 22. Describe what happens on a particle level when a liquid is at its boiling point.
23. Liquid A has a vapor pressure of 7.37 kPa at 40°C. Liquid B has a vapor pressure of 18.04 kPa at 40°C. Which liquid would evaporate faster at 40°C? Explain your answer.
24. Explain why evaporation leads to cooling of the liquid.
