States of Matter Notes
Solids
Molecular Solids
Covalent network solids
Ionic solids
Metallic solids
Crystalline Solids
Intermolecular forces
Metallic Crystals
Amorphous Solids
Allotropes
Hydrated Crystals
Anhydrous Crystal
Liquids
Cohesion
Evaporation
Pressure
Evaporation
Boiling
Vapor Pressure
Gases
Kinetic Molecular Theory
Ideal Gases
The Gas Laws
The Combined Gas Law
Moles
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Solids
There are four types of solids
1. Molecular Solids – _______________________________________________________________
2. Covalent network solids – _________________________________________________________
3. Ionic solids – formed from ions
4. Metallic solids- formed from metal atoms
There physical properties relate closely to the intermolecular forces that hold them together.
Crystalline Solids
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Arranged in fixed ___________________________ or _____________________.
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Examples:
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Ice and sodium chloride
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They have an ordered arrangement of units maximizing the space they occupy , and are
practically incompressible
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Crystalline solid: is a well ordered, definite arrangements of molecules, atoms or ions.
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Crystals have an ordered structure, which repeats itself.
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The smallest repeating unit in a crystal is a ______________.
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The unit cell is the smallest unit. It has the same symmetry as the entire crystal.
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Three dimensional packing of unit cells produces the ________________________.
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Metallic Crystals
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Composed of _____________________________ in a field of freely moving ______________
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More than 90% of naturally occurring and artificially prepared solids are crystalline. Minerals,
sand, clay, limestone, metals, alloys, carbon (diamond and graphite), salts ( NaCl, KCl etc.) , all
have crystalline structures.
Amorphous Solids
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Have a __________________ orientation of particles
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Examples of amorphous solids are ______________________________
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They are considered super-cooled liquids in which the molecules are arranged in a
random manner similar to the liquid state
Difference between crystals and amorphous solids
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Another difference between solids in a crystalline versus amorphous state is their behavior
when they are heated
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Crystals become liquids at a specific temperature, Tm (the melting point). At this temperature
physical properties of the crystalline solids change sharply.
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Amorphous solids soften gradually when they are heated.
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There tends to be a relatively wide temperature range for the melting point, a zone between the
solid and the liquid state where physical properties of the substance change gradually.
Allotropes
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Two or more distinct physical forms of a chemical element in the same physical state
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Allotropes arise because of ____________________________________ of an element’s atoms
within its molecules or crystals.
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Allotropes are in the ____________ but have vastly different chemical and physical properties.
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One of the best known examples of allotropy is carbon, which has multiple distinct allotropes
including graphite and diamond.
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Carbon atoms in diamond form a rigid, three dimensional structure, with each carbon atom
bonded to four other carbon atoms.
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In graphite the carbon atoms form stacks of flat honeycomb layers with only weak
intermolecular forces between layers.
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Elements exhibiting allotropy include arsenic, antimony, iron, oxygen, phosphorus, selenium,
sulfur, and tin.
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______________________________________________________________________________
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Because of their different internal structures, allotropic forms of an element may exhibit greatly
differing values for such physical properties as color, luster, density, hardness, odor, and
electrical and thermal conductivity.
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For example, diamond is extremely hard and does not conduct electricity, while graphite is
much softer and does conduct electricity.
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Allotropes may also differ in chemical reactivity.
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Oxygen, another allotropic element, normally exists as an odorless gas necessary for life, each of
whose molecules contains two atoms of oxygen.
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Sometimes, however, it exists as ozone, a highly reactive, poisonous gas with a sharp, pungent
odor, each of whose molecules contains three atoms of oxygen.
Hydrated Crystals
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Hydrated crystal is a crystal that contains _____________ as part of its chemical formula and
structure. It may or may not absorb water vapor from the atmosphere.
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CuSO4 . 5H2O Means water is added.
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The water is not really part of the compound (you can remove them by heating the crystals).
Anhydrous Crystal
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If the water of crystallization _____________ from blue crystals of copper (II) sulfate, a white
powder (anhydrous copper (II) sulfate) is formed.
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The formula for anhydrate of pentahydrate copper (II) sulfate (CuSO4· 5H2O) is as follows:
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CuSO4·5H2O + heat → CuSO4 + 5H2O
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Liquids
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Liquids and solids are often referred to as _____________________________ because the
particles are very close together.
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Liquids and gases are called fluids because they can be made to flow, or move. In any fluid, the
molecules themselves are in constant, random motion, colliding with each other and with the
walls of any container.
Cohesion
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Forces at work that ___________ the liquid molecules together.
Evaporation
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Evaporation is all about the energy in individual molecules, not about the average energy of a
system. The average energy can be low and the evaporation still continues.
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You might be wondering how that can happen when the temperature is low. It turns out that all
liquids can evaporate at room temperature and normal air pressure.
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Evaporation happens when atoms or molecules escape from the liquid and turn into a
vapor.
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Not all of the molecules in a liquid actually have the same energy.
Ordinary evaporation is a _____________ phenomenon some molecules have enough kinetic
energy to escape. If the container is closed, equilibrium is reached where an equal number of
molecules return to the surface. The pressure of this equilibrium is called the saturation
________________________
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Factors that Effect Evaporation
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___________________________________________________
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Concentration of substances in the air
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Flow of air
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___________________________________________________
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___________________________________________________
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Pressure
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___________________________________________________
Evaporation vs. Boiling
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Ordinary evaporation is a ________________ phenomenon since the vapor pressure is low and
since the pressure inside the liquid is equal to atmospheric pressure plus the liquid pressure,
bubbles of water vapor cannot form.
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But at the boiling point, the saturated _________________ is equal to
_____________________, bubbles form, and the vaporization becomes a volume phenomenon.
Vapor Pressure
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Vapor pressure increases with ______________________________
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At 100°C the vapor pressure of water is 760 torr (1 atm) or equal to the atmospheric pressure
on the liquid (in an open container)
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At this temperature, interior bubbles will not collapse and the water boils
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At high altitudes (i.e. up in the Mountains) the air pressure is less than at sea level. Thus, water
will boil at
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A lower temperature (the vapor pressure needed to support a bubble is lower at high altitude).
Therefore, cooking times are longer for things that need to be boiled (e.g. boiled eggs take
longer to cook at high altitudes).
Gases
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Pressure: _______________________________________________________. (need to be able
to convert to all units of pressure)
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Temperature: __________________________________________. (only use Kelvin temperature
in gas law problems.)
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Standard temperature and pressure (STP) is equal to ___________________.
Behavior of Gases
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Gas laws describe how gases behave, but they do not explain why gases behave the way they
do.
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The Kinetic Molecular Theory is a theory that is used to explain the behavior of gases
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Kinetic Molecular Theory
1) Gases contain particles that are in constant, random, straight-line motion.
2) Gas particles collide with each other and with the walls of the container. These collisions may result in
a transfer of energy among the particles, but there is no loss of energy.
3) Gas particles are separated by relatively great distance. Because of this, the volume occupied by the
particles themselves is negligible and need not be accounted for.
4) Gas particles do not attract each other.
Relationship of Pressure and Number of Gas Particles
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___________________________________________________________________________.
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Direct proportion
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For example, if you add more air to a bicycle tire, the pressure is increased.
Relationship of Pressure and Volume of a Gas
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If the molecules of a gas become ____________________ and hit the walls of the container
more often the pressure increases.
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Volume and pressure are __________________, or inversely, related.
Relationship of Temperature and Pressure of a Gas
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As temperature rises, the kinetic energy increases.
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This increase is not due to an increase in the mass of the particles, but rather to an increase in
their velocity.
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As temperature rises, the velocity of the particles increases, causing them to hit the walls of
their container more often and with greater force.
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An increase in temperature causes the ____________________________ (direct relationship)
Relationship of Temperature and Volume of a Gas
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As temperature increases, the molecules push harder on walls of the container.
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Thus ______________________________________ are directly related.
Combined Gas Law Equation
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The relationship among pressure, temperature, and volume can be mathematically represented
by an equation known as the combined gas law.
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Ideal Versus Real Gases
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Gas particles ___________________________________
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When conditions become extreme, these small forces become important.
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For example, water molecules in the atmosphere attract each other when temperatures
become cold enough. The water molecules combine to form snow or rain.
Gas particles ____________________________________
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Although gas particles themselves occupy a small volume of space under normal
conditions, as pressure increases the volume occupied by the particles can no longer be
ignored.
Ideal Gases
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A gas is said to be ideal if it behaves exactly as predicted.
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________________ and ___________________ are nearly ideal in behavior.
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Gases are most ideal at ________________ and ______________________
The Gas Laws
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Boyle’s Law
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Charles’ Law
*Temperature must be converted to Kelvin
The Combined Gas Law
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Rather than having to remember each individual law, you can memorize just one formula, and
based on the variables needed, use those and get rid of what’s not needed by using the
combined gas law.
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Moles
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Dozen is a convenient word to describe 12 of something.
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This enables you to count by a collective unit, instead of by individual items.
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1 dozen = 12 eggs
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1 mole = ______________________ atoms
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1 dozen = 12 donuts =
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1 mole = 6.023 x 10 23 atoms = __________ L
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*the only thing that differs between samples is mass
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