Chem 103 Module 6 UPDATED Exam
Questions and CORRECT Answers
Why are liquids the least common state of matter? - CORRECT ANSWER -they can exist
only within a relatively narrow range of temperatures and pressures
Differentiate between evaporation and vaporization. - CORRECT ANSWER -
Vaporization is the conversion of liquid particles to vapor at the boiling point temperature of the
material. The process of liquid converting to vapor molecules can also take place in a very
limited manner at temperatures lower than the boiling point and is called evaporation.
Explain why the vapor pressure of a liquid increases with increasing temperature. - CORRECT
ANSWER -Water molecules in the liquid state freely vibrate and rotate. As the
temperature rises, the vibrations and rotations become intense enough to overcome the forces
that keep the molecules together. The molecules begin to undergo translational motion allowing
the molecules to convert to the vapor state and these exert a pressure above the still-existing
liquid molecules called the vapor pressure of the substance. Higher temperature = greater
conversion to vapor = higher vapor pressure.
Explain water's concave meniscus in terms of cohesive and adhesive forces. - CORRECT
ANSWER -Cohesive forces are the attractions between particles of the same type, such as
the bonds between water molecules whereas adhesive forces are attractions between a particle of
one type and particles of a different type, such as the bonds between water molecule and those of
its glass container. These cohesive and adhesive forces combine to cause liquids to form a
meniscus (curved surface) in a glass tube. A liquid with strong cohesive forces, such as water,
tries to roll itself into a ball to minimize surface tension, but water is also attracted to the walls of
any tube by adhesive forces, causing the water to form a concave meniscus.
Why does diffusion take place quickly in a gas, more slowly in a liquid and not at all in a solid? -
CORRECT ANSWER -Diffusion is the non-energy-requiring movement of particles from
regions of higher concentration to regions of lower concentration. Diffusion in a liquid occurs
more slowly than in a gas since the gas particles are moving more rapidly. Solids do not show
the property of diffusion since the particles in a solid can only vibrate around a fixed point rather
than move throughout the sample.
, Evaporation - CORRECT ANSWER -The process of liquid converting to vapor molecules
Vaporization - CORRECT ANSWER -Liquid becoming a gaseous steam
Viscosity - CORRECT ANSWER -a measure of how thick or sticky a liquid is
adhesive forces - CORRECT ANSWER -attractions between a particle of one type and
particles of a different type
Cohesive forces - CORRECT ANSWER -the attractions between particles of the same
type
weak electrolytes - CORRECT ANSWER -solutes that only partially ionize
Vapor pressure - CORRECT ANSWER -the pressure exerted by vapor molecules over a
liquid
triple point - CORRECT ANSWER -the temperature and pressure conditions at which the
solid, liquid, and gaseous phases of a substance coexist
Surface tension - CORRECT ANSWER -the force that causes a liquid which is in contact
with a gas to assume a shape that has the least amount of surface area causing the surface to act
like an elastic sheet
Sublimation - CORRECT ANSWER -the conversion of a solid directly to the gas state
Strong electrolytes - CORRECT ANSWER -Solutes that ionize completely
Phase - CORRECT ANSWER -any state of matter such as solid, gas or liquid
Questions and CORRECT Answers
Why are liquids the least common state of matter? - CORRECT ANSWER -they can exist
only within a relatively narrow range of temperatures and pressures
Differentiate between evaporation and vaporization. - CORRECT ANSWER -
Vaporization is the conversion of liquid particles to vapor at the boiling point temperature of the
material. The process of liquid converting to vapor molecules can also take place in a very
limited manner at temperatures lower than the boiling point and is called evaporation.
Explain why the vapor pressure of a liquid increases with increasing temperature. - CORRECT
ANSWER -Water molecules in the liquid state freely vibrate and rotate. As the
temperature rises, the vibrations and rotations become intense enough to overcome the forces
that keep the molecules together. The molecules begin to undergo translational motion allowing
the molecules to convert to the vapor state and these exert a pressure above the still-existing
liquid molecules called the vapor pressure of the substance. Higher temperature = greater
conversion to vapor = higher vapor pressure.
Explain water's concave meniscus in terms of cohesive and adhesive forces. - CORRECT
ANSWER -Cohesive forces are the attractions between particles of the same type, such as
the bonds between water molecules whereas adhesive forces are attractions between a particle of
one type and particles of a different type, such as the bonds between water molecule and those of
its glass container. These cohesive and adhesive forces combine to cause liquids to form a
meniscus (curved surface) in a glass tube. A liquid with strong cohesive forces, such as water,
tries to roll itself into a ball to minimize surface tension, but water is also attracted to the walls of
any tube by adhesive forces, causing the water to form a concave meniscus.
Why does diffusion take place quickly in a gas, more slowly in a liquid and not at all in a solid? -
CORRECT ANSWER -Diffusion is the non-energy-requiring movement of particles from
regions of higher concentration to regions of lower concentration. Diffusion in a liquid occurs
more slowly than in a gas since the gas particles are moving more rapidly. Solids do not show
the property of diffusion since the particles in a solid can only vibrate around a fixed point rather
than move throughout the sample.
, Evaporation - CORRECT ANSWER -The process of liquid converting to vapor molecules
Vaporization - CORRECT ANSWER -Liquid becoming a gaseous steam
Viscosity - CORRECT ANSWER -a measure of how thick or sticky a liquid is
adhesive forces - CORRECT ANSWER -attractions between a particle of one type and
particles of a different type
Cohesive forces - CORRECT ANSWER -the attractions between particles of the same
type
weak electrolytes - CORRECT ANSWER -solutes that only partially ionize
Vapor pressure - CORRECT ANSWER -the pressure exerted by vapor molecules over a
liquid
triple point - CORRECT ANSWER -the temperature and pressure conditions at which the
solid, liquid, and gaseous phases of a substance coexist
Surface tension - CORRECT ANSWER -the force that causes a liquid which is in contact
with a gas to assume a shape that has the least amount of surface area causing the surface to act
like an elastic sheet
Sublimation - CORRECT ANSWER -the conversion of a solid directly to the gas state
Strong electrolytes - CORRECT ANSWER -Solutes that ionize completely
Phase - CORRECT ANSWER -any state of matter such as solid, gas or liquid
