Transcript HILL12_Lecture_06

Chemistry for Changing Times
12th Edition
Hill and Kolb
Chapter 6
Gases, Liquids, Solids,
and Intermolecular
Forces
John Singer
Jackson Community College, Jackson, MI
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Intermolecular Forces and the
States of Matter
Solids: The particles of a solid have
fixed positions and exhibit motions of
vibration.
Liquids: The particles of a liquid are free
to move within the confines of the
liquid.
Gas: The particles of a gas are far apart
and move randomly and rapidly.
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Intermolecular Forces and the
States of Matter
Melting point: The temperature at which a solid
becomes a liquid.
Vaporization: The process of a liquid becoming a
gas.
Boiling point: The temperature at which the
particles of a liquid escape and become a gas.
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Intermolecular Forces and the
States of Matter
Condensation: The process by which a gas
becomes a liquid.
Freezing: The process by which a liquid becomes
a solid. This occurs at the freezing point, which
is the same as the melting point.
Sublimation: When a solid changes directly from
the solid to the gaseous state.
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Intermolecular Forces and the
States of Matter
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Intermolecular Forces and the
States of Matter
Ionic bonds: Ionic bonds are the strongest of
forces that hold matter in the condensed states.
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Intermolecular Forces and the
States of Matter
Dipole forces: Polar molecules exist as
dipoles. These oppositely charged ends will
attract each other.
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Intermolecular Forces and the
States of Matter
Hydrogen bonds:
When a hydrogen atom
is covalently bonded to a
highly electronegative
atom like nitrogen,
oxygen, or fluorine
(N,O,F), it can exhibit an
additional polar
attraction. This attraction
is called a hydrogen
bond.
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Intermolecular Forces and the
States of Matter
Dispersion forces: Nonpolar molecules
exhibit a dynamic induced dipole. The strength
of this force increases with molecular weight
and is known as dispersion forces or London
dispersion forces.
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Intermolecular Forces and the
States of Matter
Solution: An intimate, homogeneous mixture of
two or more substances.
Solute: A substance that is dispersed in a
solution.
Solvent: A substance doing the dissolving,
usually present in greatest quantity.
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Intermolecular Forces and the
States of Matter
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Intermolecular Forces and the
States of Matter
“Like dissolves like”: Solutions form most
readily when both the solute and solvent have
similar intermolecular forces.
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Intermolecular Forces and the
States of Matter
Ionic substances dissolve in water through iondipole interactions.
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The Gas Laws
Kinetic Molecular Theory of a Gas
Postulates:
1. The particles of a gas are in rapid constant
motion.
2. The particles of a gas are tiny compared to the
distance between them.
3. There is little attraction between the particles
of a gas.
4. Collisions between gas molecules are perfectly
elastic.
5. Temperature is a measure of the average
kinetic energy of gas molecules.
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The Gas Laws
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The Gas Laws
Boyle’s law: At constant temperature, the volume
of a gas is inversely proportional to its pressure.
V α 1/P
V = a/P
PV = a
V1P1 = V2P2
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The Gas Laws
Boyle’s law: At
constant temperature,
the volume of a gas is
inversely proportional
to its pressure.
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The Gas Laws
Charles’s law: At constant pressure, the volume
of a gas is directly proportional to its absolute
temperature.
VαT
V = bT
V/T = b
V1/T1 = V2/T2
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The Gas Laws
Charles’s law: At
constant pressure, the
volume of a gas is
directly proportional to
its absolute
temperature.
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The Gas Laws
Charles’s Law
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The Gas Laws
Avogadro’s law: At fixed temperature and
pressure, the volume of a gas is directly
proportional to the amount of gas.
Vαn
V = cn
V/n = c
V1/n1 = V2/n2
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The Gas Laws
Standard temperature
and pressure:
Standard temperature
= 0 oC
Standard pressure = 1
atm
A mole of any gas at STP
occupies 22.4 L
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The Gas Laws
Combined gas law:
P1V1
T1
=
P2V2
T2
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The Gas Laws
Ideal gas law:
PV = nRT
R = 0.0821
L  atm
mol  K
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