MODULE 6 PORTAGE LEARNING CHEMISTRY
ACTUAL EXAM WITH QUESTIONS AND
CORRECT VERIFIED ANSWERS GRADED A+ ||
100% GUARANTEED PASS NEWEST VERSION
Differentiate between a crystal lattice and a unit cell - Answer A crystal lattice
is the orderly, repeating geometric pattern in which the particles of a crystalline
solid are arranged. The unit cell is the smallest section of the crystal lattice having
that arrangement of particles
Why does a phase change occur at one temperature rather than over a temperature
range? - Answer During a phase change, the temperature of the material
remains constant as all of the energy being added is being used to overcome forces
of attraction between the particles and separate them so the temperature does not
rise. Over any other portions of the temperature range, when a material is heated,
the temperature of the material will rise as the energy added causes the molecules
to move faster and demonstrate a higher temperature, which is really a measure of
the kinetic energy of the molecules
Why does diffusion take place quickly in a gas, more slowly in a liquid and not at
all in a solid? - 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.
, Explain water's concave meniscus in terms of cohesive and adhesive forces -
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.
Explain the difference in the properties of graphite and diamond which are both
pure carbon - Answer In graphite the atoms are arranged in planes which can
slide relative to one another making graphite a good solid lubricant. In diamond the
atoms are arranged in tetrahedrons which are tightly bonded together making
carbon the hardest substance known.
Explain why the vapor pressure of a liquid increases with increasing temperature -
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
Why is liquid water more dense than ice? - Answer Ice has empty spaces
between the molecules in its structure as compared to liquid water
ACTUAL EXAM WITH QUESTIONS AND
CORRECT VERIFIED ANSWERS GRADED A+ ||
100% GUARANTEED PASS NEWEST VERSION
Differentiate between a crystal lattice and a unit cell - Answer A crystal lattice
is the orderly, repeating geometric pattern in which the particles of a crystalline
solid are arranged. The unit cell is the smallest section of the crystal lattice having
that arrangement of particles
Why does a phase change occur at one temperature rather than over a temperature
range? - Answer During a phase change, the temperature of the material
remains constant as all of the energy being added is being used to overcome forces
of attraction between the particles and separate them so the temperature does not
rise. Over any other portions of the temperature range, when a material is heated,
the temperature of the material will rise as the energy added causes the molecules
to move faster and demonstrate a higher temperature, which is really a measure of
the kinetic energy of the molecules
Why does diffusion take place quickly in a gas, more slowly in a liquid and not at
all in a solid? - 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.
, Explain water's concave meniscus in terms of cohesive and adhesive forces -
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.
Explain the difference in the properties of graphite and diamond which are both
pure carbon - Answer In graphite the atoms are arranged in planes which can
slide relative to one another making graphite a good solid lubricant. In diamond the
atoms are arranged in tetrahedrons which are tightly bonded together making
carbon the hardest substance known.
Explain why the vapor pressure of a liquid increases with increasing temperature -
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
Why is liquid water more dense than ice? - Answer Ice has empty spaces
between the molecules in its structure as compared to liquid water
