Honors Chemistry
Chapter 13 Notes – States of Matter
(student’s edition)
Chapter 13 problems: 30, 35, 48, 57, 60, 66, 70, 71, 76
Chapter 13 figures: 1-3, 6-9, 12-15
13.1 The Nature of Gases
Kinetic Theory and Model for Gases:
Kinetic Theory of Gases
1. Gases are made up of molecules with lots of between
2. Particles move - pressure is caused by this motion
3. Collisions are completely
4. There are attractive or repulsive forces between molecules
5. KE =
Ideal gas: a gas that conforms to the KTG ( such gas exists).
Gas Pressure:
It is the result of simultaneous of billions of rapidly moving particles in
a gas with an object.
P =
F =
A =
SI unit for force is the
SI unit for pressure is the
The Newton’s units are
An apple exerts 1 N and a textbook exerts 15-20 N.
Ex1:Bo Diddley’s guitar exerts a force of 65 N. The body of the guitar measures
.750 m on each side. The neck of the guitar measures .750 m by .250 m.
Calculate the pressure it exerts on Bo Diddley if he lets his guitar rest on him.
Atmospheric Pressure
Liquids exert Pressure
Atmosphere - it’s like an ocean of gases
we live at the bottom - at the point of pressure
atmospheric pressure ( ) at sea level is 1 kg/cm3 (about 10 N or 4 psi)
we’re not aware of the pressure as pressure outside = pressure
Pressure is measured with a
Air pressure varies with
Increase in altitude = in air pressure
Also, a decrease in air pressure indicates an probability of rain.
Oxygen (20% of air) and Nitrogen (80%) have an average weight of
around 29 grams. If the air is saturated with water (18 grams), then the
average weight of air is going to be . Thus, the pressure that air
can exert .
Standard Pressure =
Measuring Gas Pressure - we use a
Open-ended TypeGas container Type
Boiling and Melting - remember F,C, K conversions!
K =
C =
C =
F =
NIB -Liquefication of Gases: as we increase P, or lower T, condensation is .
Oxygen condenses at -183 at Standard Pressure, - 140 at 20 atm
Critical temperature: the temperature at which a gas can no longer be no matter what the .
Critical Pressure: the pressure required to at the critical temperature.
CO2 - critical temperature of 31.1 C0 critical pressure = 73.0 atm
Kinetic Energy and Temperature:
As the KE of a substance increases, the temperature of that substance .
The Kelvin temperature is directly proportional to the .
(-273.15 C) is the temperature at which the motion of particles
theoretically stops.
13.2 The Nature of Liquids
KTG theory applied to liquids - same thing except doesn’t apply
Evaporation happens because some molecules move than others and are able to overcome the of the liquid.
Boiling: evaporation at the boiling point (rapid).
To increase the rate of evaporation - the temperature
the surface area exposed to air
the air pressure
For condensation - do the
Condensation raises the temperature of the vapor and evaporation lowers the temperature of the liquid.
Why?
Distillation: usedto separate impurities from liquid, or liquid from liquid in mixtures. It is based on evaporation and condensation.
Vapor - Liquid Equilibrium:
open container versus closed container:
when rates = equilibrium
as temperature increases, so does
Vapor Pressure and Boiling:
An increase in temperature leads to an increase in which leads to
.
Cooking depends on temperature - a low boil is better than a high boil - cooks just as fast, but uses less fuel
a comparison of vapor pressure and boiling point:
A
V.P. B
C
Temperature
when vapor pressure = atmospheric pressure, the liquid
so an alternative to raising temperature is pressure
a pressure cooker pressure so the temperature must rise higher in order to boil the food. It cooks at a higher temperature so therefore, it cooks .
we say that water boils at 100 C0 - that is true sometimes - depends on
versus
B.P. = 100C B.P. is
at sea level on top of a mountain
pressure pressure
Thus, increase air pressure = in temperature at which a liquid boils.
Boiling Point: the temperature at which a substance rapidly changes from liquid to .
Melting :
Freezing: liquid to
M.P. =
Some substances be melted or boiled. Examples are sugar, chlorates....
These substances (sodium chlorate in the chapter 9 lab decomposed
into salt and oxygen).
13.3 The Nature of Solids
Solids and Kinetic Theory: when liquids become solids, they take on a particular geometric shape and vibrate only
To be a solid, a substance must have a freezing point.
glass, wax - definite melting point - not true - technically they are
with high viscosity (resistance to flow) -
Crystals: true solids have molecules that form
the pattern is called a
the particles vibrate, but do move out of position in the lattice
crystals are determined by the of the particles and the holding them together
size of crystals are determined by the rate of - slow leads to crystals
the smallest group of particles within a crystal that retains the geometric shape of
the crystal is known as a .
Allotropes: two or more different molecular forms of the same in the
same physical state. Examples:
13.4Changes of State
Theory of Physical Phase - at the same temperature, different substances are in different phases - we learned before that this related to
solids - attractive forces - metals, ionics
liquids - forces
gases - too to stay together, particles bounce off of each other - fill the container they are in
The amount of kinetic energy (KE) determines a change in .
Example: If a liquid gets enough energy, particles can change to a gas through . Reverse: If particles lose enough energy, they can into a liquid(cold coke - hot day).
Sublimation: when a solid turns directly into a .
These solids have an unusually high .
Examples: CO2, I2, naphthalene
Phase Diagrams: A graph that represents the relationships among the
stages of a substance.
: describes the only set of conditions at which all three phases can exist in equilibrium with one another.