V. Physical Behavior of Matter

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V. Physical Behavior of Matter A
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Matter is classified as a pure substance or as a
mixture of substances. (3.1q)
Substances Substances Substances Mixtures
Elements Diatomic Elements Compounds

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The three phases of matter (solids, liquids, and
gases) have different properties. (3.1kk)
Solid Liquid Gas
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Properties of Solids

• Regular geometric pattern in the arrangement of
  the molecules called a crystal lattice
• Molecules are close together and vibrate in place
  
• Molecules do not move from place to place
• Solids are not compressible
• Definite shape and definite volume

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Properties of Liquids

• Molecules can move around (fluid)
• Molecules are farther apart than in a solid
• Liquids take the shape of their container
• Not compressible
• No definite shape but do have definite volume

The forces of attraction between the molecules
are weaker in a liquid than they are in a solid.
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Properties of Gases

• Molecules fill their container (spread out)
• Molecules are very far apart
• Molecules move in straight lines until they hit
  something (another molecule or wall of the
  container)
• No definite shape and no definite volume

The forces of attraction between the molecules
are very weak.
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Regents Question 08/02 16
Which statement correctly describes a sample of
gas confined in a sealed container? (1) It always
has a definite volume, and it takes the shape of
the container. (2) It takes the shape and the
volume of any container in which it is
confined. (3) It has a crystalline structure. (4)
It consists of particles arranged in a regular
geometric pattern.
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Regents Question 06/02 12
Which 5.0-milliliter sample of NH3 will take the
shape of and completely fill a closed
100.0-milliliter container? (1) NH3 (s) (3) NH3
(g) (2) NH3 (l) (4)NH3 (aq)
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Regents Question 06/03 16
In which material are the particles arranged in a
regular geometric pattern? (1) CO2 (g) (2)
NaCl(aq) (3) H2O(l) (4) C12H22O11 (s)
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A pure substance (element or compound) has a
constant composition and constant properties
throughout a given sample, and from sample to
sample. (3.1r)
All substances are homogeneous.
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Elements are substances that are composed of
atoms that have the same atomic number. Elements
cannot be broken down by chemical change. (3.1u)
There are more than 100 different
elements Elements are represented by chemical
symbols The first letter of the symbol is always
a capital letter the rest are lower case
A temporary symbol
Nitrogen
Neon
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Some elements are diatomic. They come in pairs
when not combined with other elements.

• H O N Cl Br I F

• Diatomic Elements
• Hydrogen
• Oxygen
• Nitrogen
• Chlorine
• Bromine
• Iodine
• Fluorine

Neon is a monatomic element
Nitrogen is a diatomic element
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Compounds are substances that are composed of two
or more different elements chemically combined.

• The elements in a compound are in fixed
  proportions
• A compound can only be decomposed by chemical
  means
• Compounds are represented by chemical formulas
• Compounds are electrically neutral

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Using particle diagrams to represent elements,
compounds and mixtures.
Compound
Element
Diatomic element
Mixture
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Regents Question 08/02 6
Which species represents a chemical compound? (1)
N2 (3) Na (2) NH4 (4) NaHCO3
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Compounds are made up of more than one type of
element. (Look for more than one capital letter.)
Compounds are electrically neutral.
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Regents Question 06/03 9
Which substance can be decomposed by a chemical
change? (1) Co (2) CO (3) Cr (4) Cu
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Mixtures are composed of two or more different
substances that can be separated by physical
means.
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Regents Question 06/02 43
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Regents Question 08/02 51
On a field trip, Student X and Student Y
collected two rock samples. Analysis revealed
that both rocks contained lead and sulfur. One
rock contained a certain percentage of lead and
sulfur by mass, and the other rock contained a
different percentage of lead and sulfur by mass.
Student X stated that the rocks contained two
different mixtures of lead and sulfur. Student Y
stated that the rocks contained two different
compounds of lead and sulfur. Their teacher
stated that both students could be correct. Draw
particle diagrams in each of the rock diagrams
provided in your answer booklet to show how
Student Xs and Student Ys explanations could
both be correct. Use the symbols in the key
provided in your answer booklet to sketch lead
and sulfur atoms.
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Regents Question 08/02 51 Answer
Draw particle diagrams in each of the rock
diagrams provided in your answer booklet to show
how Student Xs and Student Ys explanations
could both be correct. Use the symbols in the key
provided in your answer booklet to sketch lead
and sulfur atoms.
Student X
Student Y
Rock A Rock B
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When different substances are mixed together, a
homogeneous or heterogeneous mixture is formed.
(3.1s)
A homogeneous mixture is called a solution A
solution in which something is dissolved in water
is called an aqueous solution NaCl(aq) means that
sodium chloride (table salt) is dissolved in
water and is therefore a homogenous mixture. (aq)
stands for aqueous An alloy is a solution of
metals eg. brass, bronze
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Regents Question 06/03 15
Which of these terms refers to matter that could
be heterogeneous? (1) element (2) mixture (3)
compound (4) solution
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The proportions of components in a mixture can be
varied. Each component in a mixture retains its
original properties. (3.1t)
Two mixtures of Hydrogen (H2) and Neon (Ne)
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Differences in properties such as density,
particle size, molecular polarity, boiling point
and freezing point, and solubility permit
physical separation of the components of the
mixture. (3.1nn)
Chromatography, Filtration, Dissolving,
Distillation, Crystallization
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Regents Question 01/04 12
A bottle of rubbing alcohol contains both
2-propanol and water. These liquids can be
separated by the process of distillation because
the 2-propanol and water (1) have combined
chemically and retain their different boiling
points (2) have combined chemically and have the
same boiling point (3) have combined physically
and retain the different boiling points (4) have
combined physically and have the same boiling
point
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Density and polarity
Particle size
Boiling point
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Energy can exist in different forms, such as
chemical, electrical, electromagnetic, thermal,
mechanical, and nuclear. (4.1a)
Kinetic energy the energy of motion Potential
energy the energy of position (stored energy)
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The amount of thermal energy contained in the
molecules depends on how fast they are moving and
how many molecules there are.

• The total kinetic energy of all the molecules
  combined is called thermal energy
• Thermal energy is a result of the Kinetic Energy
  of the molecules motion (molecules are always
  moving.)
• Which can melt more ice a small cup of hot water
  or a swimming pool of cold water?

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Heat is a transfer of energy (usually thermal
energy) from a body of higher temperature to a
body of lower temperature. Thermal energy is the
energy associated with the random motion of atoms
and molecules. (4.2a)
The Law of Conservation of Energy states that
energy can neither be created nor destroyed.
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Heat is transferred to different materials at
different rates.

• The specific heat capacity (C) determines the
  rate at which heat will be absorbed.
• The specific heat capacity for water is 4.18J/g
• The quantity of heat absorbed (Q) can be
  calculated by QmC?T
• mmass ?Tchange in temperature

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Temperature is a measurement of the average
kinetic energy of the particles in a sample of
material. Temperature is not a form of energy.
(4.2b)
Two temperature scales used in chemistry are
Celsius and Absolute The unit of temperature in
the Celsius scale is the degree (ºC) The unit of
temperature on the Absolute scale is the Kelvin
(K)
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Regents Question 06/02 16
Which change in the temperature of a 1-gram
sample of water would cause the greatest increase
in the average kinetic energy of its
molecules? (1) 1C to 10C (3) 50C to 60C (2)
10C to 1C (4) 60C to 50C
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To convert between absolute and Celsius
temperature scales use KºC273
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The concepts of kinetic and potential energy can
be used to explain physical processes that
include fusion (melting), solidification
(freezing), vaporization (boiling, evaporation),
condensation, sublimation, and deposition. (4.2c)
Add energy (endothermic) subliming
melting boiling
SOLID LIQUID GAS
Remove energy (exothermic) freezing depositing condensing

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Regents Question 06/03 17
Which change is exothermic? (1) freezing of
water (2) melting of iron (3) vaporization of
ethanol (4) sublimation of iodine
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A change in phase is a change in Potential
Energy, not Kinetic Energy
Boiling Point
Potential energy changes so temperature doesnt
Melting Point
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Energy and phase changes

• AB - solid warms up (KE inc/PE constant)
• BC- solid melts (KE constant/PE inc)
• CD liquid warms up (KE inc/PE constant)
• DE- liquid boils (KE constant/PE inc)

• EF gas warms (KE inc/PE constant)

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Regents Question 06/02 28
As ice melts at standard pressure, its
temperature remains at 0C until it has
completely melted. Its potential energy (1)
decreases (2) increases (3) remains the same
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Regents Question 08/02 54
A sample of water is heated from a liquid at 40C
to a gas at 110C. The graph of the heating curve
is shown in your answer booklet. a On the
heating curve diagram provided in your answer
booklet, label each of the following
regions Liquid, only Gas, only Phase change
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Regents Question contd
b For section QR of the graph, state what is
happening to the water molecules as heat is
added. c For section RS of the graph, state
what is happening to the water molecules as heat
is added.
They move faster, their temperature increases.
Their intermolecular bonds are breaking, their
potential energy is increasing.
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Regents Question 01/02 47
What is the melting point of this substance? (1)
30C (3) 90C (2) 55C (4) 120C
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The quantity of energy absorbed or released
during a phase change can be calculated using the
Heat of Fusion or Heat of Vaporization

• Melting (fusion) or freezing (solidification)
• QmHf where Hf is the heat of fusion
• (for water 333.6 J/g)
• Boiling (vaporization) or condensing
• QmHv where Hv is the heat of vaporization
• (for water 2259 J/g)

Hf and Hv are given to Table B m is the mass
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Regents Question 08/02 24
In which equation does the term heat represent
heat of fusion? (1) NaCl(s) heat ? NaCl(l) (2)
NaOH(aq) HCl(aq) ? NaCl(aq) H2O(l) heat (3)
H2O(l) heat ? H2O(g) (4) H2O(l) HCl(g)
?H3O(aq) Cl (aq) heat
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Fusion refers to melting.
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Melting Point

• The temperature at which a liquid and a solid are
  in equilibrium
• The melting point for ice is 0ºC
• The melting point of a substance is the same as
  its freezing point

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Regents Question 08/02 5
Given the equation H2O(s) ? H2O(l) At which
temperature will equilibrium exist when the
atmospheric pressure is 1 atm? (1) 0 K (3) 273
K (2) 100 K (4) 373 K
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KC 273
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Regents Question 08/02 18
The solid and liquid phases of water can exist in
a state of equilibrium at 1 atmosphere of
pressure and a temperature of (1) 0C (3)
273C (2) 100C (4) 373C
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Regents Question 06/03 41
The freezing point of bromine is (1) 539C (2)
539C (3) 7C (4) 7C
See Table S Melting point is the same as freezing
point Convert K to C (KC273)
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A physical change results in the rearrangement of
existing particles in a substance. A chemical
change results in the formation of different
substances with changed properties. (3.2a)

• Physical Changes
• Changes in phase
• Melting
• Boiling
• Subliming
• Dissolving

• Chemical Changes
• Any chemical reaction
• Synthesis
• Decomposion
• Single Replacment
• Double Replacement
• Combustion (burning)

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Regents Question 06/03 18
Which type of change must occur to form a
compound? (1) chemical (2) physical (3)
nuclear (4) phase
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Chemical and physical changes can be exothermic
or endothermic. (4.1b)

• Exothermic
• Potential energy decreases
• Releases energy
• ?H is negative
• Energy is on the right
• 2H2 O2 2H2O energy

• Endothermic
• Potential energy increases
• Absorbs energy
• ?H is positive
• Energy is on the left
• 2H2O energy 2H2 O2

PE
PE
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Table H the vapor pressure of four liquids at
various temperatures.
As temp inc, vapor pressure inc.
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Regents Question 06/03 40

• According to Reference Table H, what is the vapor
  pressure of propanone at 45C?
• 22 kPa
• 33 kPa
• 70. kPa
• (4) 98 kPa

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A liquid will boil when its vapor pressure equals
the atmospheric pressure.

• Raising the temperature will increase the vapor
  pressure of the liquid
• Lowering the atmospheric pressure will lower the
  boiling point
• On top of a high mountain, water boils at a
  temperature below 100?C

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Standard pressure is 101.3 kilopascals (kPa) or
1 atmoshpere (atm)
The normal boiling point occurs when the
atmospheric pressure is 101.3 kPa (standard
pressure)
The normal boiling point of ethanol is 80ºC.
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Regents Question 08/02 28
As the pressure on the surface of a liquid
decreases, the temperature at which the liquid
will boil (1) decreases (2) increases (3) remains
the same
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Regents Question 08/02 30
As the temperature of a liquid increases, its
vapor pressure (1) decreases (2) increases (3)
remains the same
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Regents Question 08/02 44
The vapor pressure of a liquid is 0.92 atm at
60C. The normal boiling point of the liquid
could be (1) 35C (3) 55C (2) 45C (4) 65C
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The normal boiling point is the temperature at
which a liquid boils when the atmospheric
pressure is standard pressure (1 atm or 101.3 kPa)
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Regents Question 01/03 68
What is the vapor pressure of liquid A at 70C?
Your answer must include correct units.
700 mm Hg
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Regents Question 01/03 69
At what temperature does liquid B have the same
vapor pressure as liquid A at 70C? Your answer
must include correct units.
113C
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Regents Question 01/03 70
Which liquid will evaporate more rapidly? Explain
your answer in terms of intermolecular forces.
Liquid A will evaporate more rapidly because, at
any temperature, it has the weaker
intermolecular forces.