CEM 141 Exam 1
A. Solid - ANS-The boiling point of neon is -246 degrees C and the melting point of neon is -249
degrees C. What state is neon at -260 degrees C.
A. Solid
B. Liquid
C. Gas
A. The atom is mostly empty space with a very small, dense nucleus. - ANS-Choose the best
claim that can be used to explain the results of Rutherford's experiment...
A. The atom is mostly empty space with a very small, dense nucleus.
B. The atom is made of positively charged matter with electrons embedded in it.
A. The positively charged alpha particles were deflected by the repulsive interaction with the
positive nucleus; since only a few were deflected the nucleus must take up a very small volume
of the atom. - ANS-Choose the best reasoning that can be used to explain the results of
Rutherford's experiment...
A. The positively charged alpha particles were deflected by the repulsive interaction with the
positive nucleus; since only a few were deflected the nucleus must take up a very small volume
of the atom.
B. When the alpha particles get near the nucleus they are attracted by the strong nuclear force
which alters their trajectory.
A. Where the potential energy is at a minimum. - ANS-Consider a system where two helium are
approaching from a distance. The distance between the two helium atoms where the system
would be the most stable is:
A. Where the potential energy is at a minimum.
B. Where the kinetic energy is at a minimum.
C. Where the KE and PE are equal.
D. Where the PE is a high as possible.
All are true. - ANS-Which of these statements are true?
I. All neutral atoms and molecules attract each other.
II. London dispersion forces increase as the size of the electron cloud increases.
III. It takes energy to overcome the attractions between particles.
IV. Energy is released to the surroundings when atoms form a stable interaction.
B. Explains the underlying cause of a range of phenomena. - ANS-The atomic theory of matter
is an example of a scientific theory. What distinguishes it from a scientific law such as the law of
gravity? The atomic theory:
A. Describes a single phenomenon.
B. Explains the underlying cause of a range of phenomena.
, C. Can be used to predict.
D. Must be revised if evidence arises that contradicts it.
B. Gaseous hydrogen molecules. - ANS-The boiling point of hydrogen is 20K. Describe the
particles present in a container of hydrogen at 25K.
A. Gaseous hydrogen atoms.
B. Gaseous hydrogen molecules.
C. Hydrogen atoms in the liquid state.
D. Hydrogen molecules in the liquid state.
B. Most alpha particles went straight through, only a few were deflected. - ANS-Choose the best
evidence that can be used to explain the results of Rutherford's experiment...
A. The alpha particles were deflected by the magnetic and electric fields in the apparatus.
B. Most alpha particles went straight through, only a few were deflected.
B. The electrostatic force would become weaker. - ANS-How would the strength of the
electrostatic force change if the distance between two charged objects increased?
A. The electrostatic force would become stronger.
B. The electrostatic force would become weaker.
C. The electrostatic force acting on object one would become stronger while the electrostatic
force acting on object two would become weaker.
D. It is impossible to say from the information given.
C. As more bromine molecules get more energy, they can overcome the electrostatic forces of
attraction and the bromine molecules can escape into the gas phase. - ANS-If you put bromine
liquid in a pan on the stove and heat it up the bromine will boil. What is the mechanism by which
this happens?
A. Bromine molecules collide with the hot pan and energy is transferred to these bromine
molecules.
B. Higher energy bromine molecules collide with lower energy molecules and energy is
transferred.
C. As more bromine molecules get more energy, they can overcome the electrostatic forces of
attraction and the bromine molecules can escape into the gas phase.
D. As more bromine molecules get more energy, they can overcome the covalent bonds
between the molecules and the bromine atoms can escape into the gas phase.
C. I and III - ANS-Which of the following are correct statements?
I. Covalent bonds are interactions within molecules.
II. Covalent bonds are interactions between separate molecules.
III. LDFs are typically interactions between separate molecules.
IV. LDFs are within molecules.
A. I B. II C. I and III D. I and IV
C. M3 and M4. - ANS-Consider the following four objects:
A. Solid - ANS-The boiling point of neon is -246 degrees C and the melting point of neon is -249
degrees C. What state is neon at -260 degrees C.
A. Solid
B. Liquid
C. Gas
A. The atom is mostly empty space with a very small, dense nucleus. - ANS-Choose the best
claim that can be used to explain the results of Rutherford's experiment...
A. The atom is mostly empty space with a very small, dense nucleus.
B. The atom is made of positively charged matter with electrons embedded in it.
A. The positively charged alpha particles were deflected by the repulsive interaction with the
positive nucleus; since only a few were deflected the nucleus must take up a very small volume
of the atom. - ANS-Choose the best reasoning that can be used to explain the results of
Rutherford's experiment...
A. The positively charged alpha particles were deflected by the repulsive interaction with the
positive nucleus; since only a few were deflected the nucleus must take up a very small volume
of the atom.
B. When the alpha particles get near the nucleus they are attracted by the strong nuclear force
which alters their trajectory.
A. Where the potential energy is at a minimum. - ANS-Consider a system where two helium are
approaching from a distance. The distance between the two helium atoms where the system
would be the most stable is:
A. Where the potential energy is at a minimum.
B. Where the kinetic energy is at a minimum.
C. Where the KE and PE are equal.
D. Where the PE is a high as possible.
All are true. - ANS-Which of these statements are true?
I. All neutral atoms and molecules attract each other.
II. London dispersion forces increase as the size of the electron cloud increases.
III. It takes energy to overcome the attractions between particles.
IV. Energy is released to the surroundings when atoms form a stable interaction.
B. Explains the underlying cause of a range of phenomena. - ANS-The atomic theory of matter
is an example of a scientific theory. What distinguishes it from a scientific law such as the law of
gravity? The atomic theory:
A. Describes a single phenomenon.
B. Explains the underlying cause of a range of phenomena.
, C. Can be used to predict.
D. Must be revised if evidence arises that contradicts it.
B. Gaseous hydrogen molecules. - ANS-The boiling point of hydrogen is 20K. Describe the
particles present in a container of hydrogen at 25K.
A. Gaseous hydrogen atoms.
B. Gaseous hydrogen molecules.
C. Hydrogen atoms in the liquid state.
D. Hydrogen molecules in the liquid state.
B. Most alpha particles went straight through, only a few were deflected. - ANS-Choose the best
evidence that can be used to explain the results of Rutherford's experiment...
A. The alpha particles were deflected by the magnetic and electric fields in the apparatus.
B. Most alpha particles went straight through, only a few were deflected.
B. The electrostatic force would become weaker. - ANS-How would the strength of the
electrostatic force change if the distance between two charged objects increased?
A. The electrostatic force would become stronger.
B. The electrostatic force would become weaker.
C. The electrostatic force acting on object one would become stronger while the electrostatic
force acting on object two would become weaker.
D. It is impossible to say from the information given.
C. As more bromine molecules get more energy, they can overcome the electrostatic forces of
attraction and the bromine molecules can escape into the gas phase. - ANS-If you put bromine
liquid in a pan on the stove and heat it up the bromine will boil. What is the mechanism by which
this happens?
A. Bromine molecules collide with the hot pan and energy is transferred to these bromine
molecules.
B. Higher energy bromine molecules collide with lower energy molecules and energy is
transferred.
C. As more bromine molecules get more energy, they can overcome the electrostatic forces of
attraction and the bromine molecules can escape into the gas phase.
D. As more bromine molecules get more energy, they can overcome the covalent bonds
between the molecules and the bromine atoms can escape into the gas phase.
C. I and III - ANS-Which of the following are correct statements?
I. Covalent bonds are interactions within molecules.
II. Covalent bonds are interactions between separate molecules.
III. LDFs are typically interactions between separate molecules.
IV. LDFs are within molecules.
A. I B. II C. I and III D. I and IV
C. M3 and M4. - ANS-Consider the following four objects:
