CEM 141 Final Exam Test Questions with Answers
Graded A+
Why are alpha particles deflected by the Energy is transferred via collisions.
nucleus? - ANSWERS - Because both the
alpha particles and the nucleus are positively
charged and so the alpha particle is repelled. Where would two atoms of He be most stable on
a PE curve? - ANSWERS - The PE well,
where the attractive and repulsive forces are
Is this statement (Dalton's Theory) true or false equal and the system is most stable.
and why?
"All atoms of an element are identical and have
the same mass and properties." - For a pencil sitting on a desk, what forces are
ANSWERS - False. acting upon the pencil? - ANSWERS - Both
Atoms of the same element can have different gravitational and electrostatic.
numbers of neutrons.
If the PE increases as two particles approach,
What is the evidence that electrons are what are they most likely? - ANSWERS -
subatomic particles? - ANSWERS - The Two protons (positively charged/same charge).
nature of the electron is independent of the
material from which it emerges.
How do atoms know that temperature is
increasing? - ANSWERS - Thermal energy
Example of a theory (explains) - is transferred upon collision with other atoms.
ANSWERS - The properties of matter can
be EXPLAINED by understanding that matter is
composed of atoms that interact and move in What two atoms would have the greatest
various predictable ways. gravitational forces? Two 10g separated by 10
meters. Or, one 100g and one 1g separated by 5
meters?
Why is the boiling point of iodine higher than that m1m2/r^2 - ANSWERS - 100g and 1g
of bromine? - ANSWERS - Because iodine separated by 5 meters.
has a larger more polarizable electron cloud. The (100)(1)/(25) = 4
electrostatic attraction between the iodine
molecules requires more energy to overcome.
In the solid state, atoms of xenon are held
together by.. - ANSWERS - London
When bromine melts, what is happening? - Dispersion Forces ONLY because Xenon is a
ANSWERS - Attractive forces between noble gas that cannot bond together.
molecules are overcome.
What does a lower PE well mean?
When oxygen freezes, what is happening with What does a further right position on the PE
the forces and energy changes during this graph mean? - ANSWERS - More energy
process? - ANSWERS - New LDFs are needed to break interactions.
formed. Energy is released to the surroundings. Longer bond.
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Graded A+
Why are alpha particles deflected by the Energy is transferred via collisions.
nucleus? - ANSWERS - Because both the
alpha particles and the nucleus are positively
charged and so the alpha particle is repelled. Where would two atoms of He be most stable on
a PE curve? - ANSWERS - The PE well,
where the attractive and repulsive forces are
Is this statement (Dalton's Theory) true or false equal and the system is most stable.
and why?
"All atoms of an element are identical and have
the same mass and properties." - For a pencil sitting on a desk, what forces are
ANSWERS - False. acting upon the pencil? - ANSWERS - Both
Atoms of the same element can have different gravitational and electrostatic.
numbers of neutrons.
If the PE increases as two particles approach,
What is the evidence that electrons are what are they most likely? - ANSWERS -
subatomic particles? - ANSWERS - The Two protons (positively charged/same charge).
nature of the electron is independent of the
material from which it emerges.
How do atoms know that temperature is
increasing? - ANSWERS - Thermal energy
Example of a theory (explains) - is transferred upon collision with other atoms.
ANSWERS - The properties of matter can
be EXPLAINED by understanding that matter is
composed of atoms that interact and move in What two atoms would have the greatest
various predictable ways. gravitational forces? Two 10g separated by 10
meters. Or, one 100g and one 1g separated by 5
meters?
Why is the boiling point of iodine higher than that m1m2/r^2 - ANSWERS - 100g and 1g
of bromine? - ANSWERS - Because iodine separated by 5 meters.
has a larger more polarizable electron cloud. The (100)(1)/(25) = 4
electrostatic attraction between the iodine
molecules requires more energy to overcome.
In the solid state, atoms of xenon are held
together by.. - ANSWERS - London
When bromine melts, what is happening? - Dispersion Forces ONLY because Xenon is a
ANSWERS - Attractive forces between noble gas that cannot bond together.
molecules are overcome.
What does a lower PE well mean?
When oxygen freezes, what is happening with What does a further right position on the PE
the forces and energy changes during this graph mean? - ANSWERS - More energy
process? - ANSWERS - New LDFs are needed to break interactions.
formed. Energy is released to the surroundings. Longer bond.
1/4
