CEM 141 Final Exam 2025/2026 Exam
Questions with 100% Correct Answers |
Latest Update
Why are alpha particles deflected by the nucleus? - 🧠 ANSWER ✔✔Because both
the alpha particles and the nucleus are positively charged and so the alpha particle
is repelled.
Is this statement (Dalton's Theory) true or false and why?
"All atoms of an element are identical and have the same mass and properties." - 🧠
ANSWER ✔✔False.
Atoms of the same element can have different numbers of neutrons.
What is the evidence that electrons are subatomic particles? - 🧠 ANSWER ✔✔The
nature of the electron is independent of the material from which it emerges.
, Example of a theory (explains) - 🧠 ANSWER ✔✔The properties of matter can be
EXPLAINED by understanding that matter is composed of atoms that interact and
move in various predictable ways.
Why is the boiling point of iodine higher than that of bromine? - 🧠 ANSWER
✔✔Because iodine has a larger more polarizable electron cloud. The electrostatic
attraction between the iodine molecules requires more energy to overcome.
When bromine melts, what is happening? - 🧠 ANSWER ✔✔Attractive forces
between molecules are overcome.
When oxygen freezes, what is happening with the forces and energy changes
during this process? - 🧠 ANSWER ✔✔New LDFs are formed. Energy is released
to the surroundings. Energy is transferred via collisions.
Where would two atoms of He be most stable on a PE curve? - 🧠 ANSWER
✔✔The PE well, where the attractive and repulsive forces are equal and the system
is most stable.
For a pencil sitting on a desk, what forces are acting upon the pencil? - 🧠
ANSWER ✔✔Both gravitational and electrostatic.
Questions with 100% Correct Answers |
Latest Update
Why are alpha particles deflected by the nucleus? - 🧠 ANSWER ✔✔Because both
the alpha particles and the nucleus are positively charged and so the alpha particle
is repelled.
Is this statement (Dalton's Theory) true or false and why?
"All atoms of an element are identical and have the same mass and properties." - 🧠
ANSWER ✔✔False.
Atoms of the same element can have different numbers of neutrons.
What is the evidence that electrons are subatomic particles? - 🧠 ANSWER ✔✔The
nature of the electron is independent of the material from which it emerges.
, Example of a theory (explains) - 🧠 ANSWER ✔✔The properties of matter can be
EXPLAINED by understanding that matter is composed of atoms that interact and
move in various predictable ways.
Why is the boiling point of iodine higher than that of bromine? - 🧠 ANSWER
✔✔Because iodine has a larger more polarizable electron cloud. The electrostatic
attraction between the iodine molecules requires more energy to overcome.
When bromine melts, what is happening? - 🧠 ANSWER ✔✔Attractive forces
between molecules are overcome.
When oxygen freezes, what is happening with the forces and energy changes
during this process? - 🧠 ANSWER ✔✔New LDFs are formed. Energy is released
to the surroundings. Energy is transferred via collisions.
Where would two atoms of He be most stable on a PE curve? - 🧠 ANSWER
✔✔The PE well, where the attractive and repulsive forces are equal and the system
is most stable.
For a pencil sitting on a desk, what forces are acting upon the pencil? - 🧠
ANSWER ✔✔Both gravitational and electrostatic.
