CHEM 1212 Exam Questions and Answers| New Update with 100% Correct Answers
In terms of their bulk properties, how do liquids and solids differ? How are they similar?
Similar:
-Matter composed of atoms, ions, or molecules
-Incompressible and have similar densities that are both much larger than those of gases
Different:
-Liquids have no fixed shape
-Solids are rigid
In terms of the kinetic molecular theory, in what ways are liquids similar to solids? In what ways
are liquids different from solids? Solids
-Tightly packed
-Regular pattern
-Vibrate in fixed positions
-Do not move in relation to another
Liquids
-close together with no regular pattern
-Move past each other
-Remain in constant contact
In terms of the kinetic molecular theory, in what ways are LIQUIDS similar to GASES? In what
ways are liquids different from gases? Similar:
-atoms or molecules are free to move from one position to another
Differ:
-Particles of a liquid are confined to the shape of the vessel in which they are placed
-Gas will expand without limit to fill the space into which it is placed
, Explain why liquids assume the shape of any container into which they are poured, whereas
solids are rigid and retain their shape.
What is the evidence that all neutral atoms and molecules exert attractive forces on each
other? All atoms and molecules will condense into a liquid or solid in which the attractive
forces exceed the kinetic energy of the molecules, at sufficiently low temperature.
Dispersion Force Atom develops temporary dipole moment when electrons are distributed
asymmetrically in the nucleus (more prevalent in large atoms). e- in 2nd atom attracted toward
positive end of 1st atom, sets up a dipole in the 2nd atom. Net result: rapidly fluctuating,
temporary dipoles that attract one another
-Example: Argon / Radon
Dipole-dipole attraction From an electrostatic attraction of positive end of one polar
molecule for the neg end of another polar molecule
Example: ICl molecules attract one another
Hydrogen Bond Form when hydrogen atom is bonded to one or more electronegative atoms
(Fl, O, N atoms)
-Electrostatic attraction between the partially pos H atom in one molecule and partially neg H
atom in another molecule gives rise to a strong dipole-dipole interaction called H bond
The types of intermolecular forces in a substance are identical whether it is a solid, a liquid, or a
gas. Why then does a substance change phase from a gas to a liquid or to a solid? particles
kinetic energy provides the energy required to overcome the attractive forces and thus increase
the distance between particles
Why do the boiling points of the noble gases increase in the order He < Ne < Ar < Kr < Xe?
London forces typically increase as # of e- increase
Explain why the boiling points of Neon and HF differ.
In terms of their bulk properties, how do liquids and solids differ? How are they similar?
Similar:
-Matter composed of atoms, ions, or molecules
-Incompressible and have similar densities that are both much larger than those of gases
Different:
-Liquids have no fixed shape
-Solids are rigid
In terms of the kinetic molecular theory, in what ways are liquids similar to solids? In what ways
are liquids different from solids? Solids
-Tightly packed
-Regular pattern
-Vibrate in fixed positions
-Do not move in relation to another
Liquids
-close together with no regular pattern
-Move past each other
-Remain in constant contact
In terms of the kinetic molecular theory, in what ways are LIQUIDS similar to GASES? In what
ways are liquids different from gases? Similar:
-atoms or molecules are free to move from one position to another
Differ:
-Particles of a liquid are confined to the shape of the vessel in which they are placed
-Gas will expand without limit to fill the space into which it is placed
, Explain why liquids assume the shape of any container into which they are poured, whereas
solids are rigid and retain their shape.
What is the evidence that all neutral atoms and molecules exert attractive forces on each
other? All atoms and molecules will condense into a liquid or solid in which the attractive
forces exceed the kinetic energy of the molecules, at sufficiently low temperature.
Dispersion Force Atom develops temporary dipole moment when electrons are distributed
asymmetrically in the nucleus (more prevalent in large atoms). e- in 2nd atom attracted toward
positive end of 1st atom, sets up a dipole in the 2nd atom. Net result: rapidly fluctuating,
temporary dipoles that attract one another
-Example: Argon / Radon
Dipole-dipole attraction From an electrostatic attraction of positive end of one polar
molecule for the neg end of another polar molecule
Example: ICl molecules attract one another
Hydrogen Bond Form when hydrogen atom is bonded to one or more electronegative atoms
(Fl, O, N atoms)
-Electrostatic attraction between the partially pos H atom in one molecule and partially neg H
atom in another molecule gives rise to a strong dipole-dipole interaction called H bond
The types of intermolecular forces in a substance are identical whether it is a solid, a liquid, or a
gas. Why then does a substance change phase from a gas to a liquid or to a solid? particles
kinetic energy provides the energy required to overcome the attractive forces and thus increase
the distance between particles
Why do the boiling points of the noble gases increase in the order He < Ne < Ar < Kr < Xe?
London forces typically increase as # of e- increase
Explain why the boiling points of Neon and HF differ.
