Transcript UNIT 1: MATTER AND ENERGY (Review Book Topic 4)

UNIT 1: MATTER AND ENERGY
(Review Book Topic 4)
How does the proximity of atoms or molecules to each other affect
properties they exhibit?
How can we explain phase changes in terms of energy?
How can we explain the behavior of gases?
How can we explain the behavior of gases in terms of pressure?
How can we explain the relationships between P,T, & V?
What kinds of matter are there, and how can you turn one form of
matter into another form?
HONORS CHEMISTRY – MS. ARGENZIO
Thursday 9/11/14 – A DAY
AIM: How does the proximity of atoms or molecules to each
other affect properties they exhibit?
DO NOW: Answer the following questions:
1. What is matter?
2. What are the different states of matter and list one
example of each?
Phases of Matter
Lets Review……
What is matter???
Anything that:
Has mass
Takes up space
STATES OF MATTER
There are 3 states of matter
SOLIDS
Particles tightly packed together
Particle Movement type: vibrate
Has definite shape
Has definite volume
Examples
LIQUIDS
Particles are moderately packed
together
Particle movement: Vibrate and Rotate
No definite shape, Takes the shape of its container
Has Definite Volume
Examples
GAS (vapor)
Particles are loosely packed
Particle movement: Vibrate, Rotate &
bounce off container
Has No Definite Shape
Has No Definite Volume
Examples
Thursday 10/10/13 – C DAY
AIM: How can we explain
phase changes in terms of
energy?
Melting
change from SOLID to LIQUID
Heat is absorbed (ENDOTHERMIC)
Molecules spread out
Fusion
 -no temp change even though energy is added
Average KE of particles remains the same
Particles absorb heat as Potential Energy
FREEZING
change from LIQUID to SOLID
Heat is removed (EXOTHERMIC)
Molecules get closer
Solidification
no temp change
P.E. decreases
HEAT OF FUSION
Amount of heat needed to melt a
solid under normal conditions
Freezing requires same amount of
heat as melting (it is released instead
of absorbed)
Table T for equation: q = mHf
EVAPORATION
LIQUID to GAS
Heat is absorbed
Molecules spread out
Vaporization
No change in temp
 gain P.E.
CONDENSATION
GAS to LIQUID
Heat is removed
Molecules get closer
HEAT OF VAPORIZATION
Amount of heat needed to convert a
liquid to gas under normal conditions
Condensation requires same
amount of heat as vaporization (it is
released instead of absorbed)
Table T for equation:q = mHv
SUBLIMATION/
DEPOSITION
Sublimation: SOLID to GAS
Molecules spread out
 Deposition: GAS to SOLID
Molecules get closer
AIM: How can we
represent/calculate the energy
associated with phase changes?
DO NOW:
1. Take out reference table, and pen/pencil and HW
2. Answer the following questions :
- What phase changes are endothermic?
- What phase changes are exothermic?
- What happens to average kinetic energy during a
phase change? Temperature?
- What happens to potential energy during a phase
change?
HEATING/COOLING
CURVES
Graph of temp vs. Time
Showing the phase changes of a
substance
Time increases but temp stays
constant represent phase changes
with no slope
Places with a slope indicate temp
changes
HEATING/COOLING
CURVES
Time
HEATING AND COOLING CURVE QUESTIONS
1.
What caused the water to change phases during this
experiment? Heating the water
2.
What is happening at the two plateaus on the graph?
Phase change
3.
Why doesn’t the kinetic energy change at these spots?
Temperature doesn’t change
4.
The melting point of water occurs at the same temperature
freezing
as the _________________________
point of water.
5.
What other phase changes happen at the same
temperature? Condensation and Evaporation
Energy Changes Associated with Phase
Changes
Energy: the ability to do work or produce heat
Types: Light energy ( radio waves, microwaves, etc.), heat,
mechanical, chemical, nuclear etc.
Potential energy: Stored energy
Ex) ball at the top of a hill, chemical bonds (attachments) between
atoms of a substance
Kinetic Energy: (KE) the energy of motion
Energy Changes Associated with Phase
Changes
Temperature: Measure of average kinetic energy of the
particles of a substance
Heat : The flow of energy due to a temperature difference.
Heat always flows from high temp to low temp
Kelvin Temperature: scale that is directly proportional to
average KE (See Table T )
Energy Changes Associated with Phase
Changes – Heat Formulas
Heat of Fusion (q=mHf) : Clues to use this formula would be the following
words- melting, freezing, solidification, crystallization, solid to liquid, liquid to
solid (this value for water is located on Reference Table B)
Heat of Vaporization (q=mHv) : : Clues to use this formula would be the
following words – evaporation, vaporization, condensation, liquid to gas, gas to
liquid, steam (this value for water is located on Reference Table B)
Anytime there is a temperature change (a substance cooling or being heated)
you would use the q=mcΔT
Where ΔT = Tfinal – Tinitial
HEAT CALCULATION PRACTICE
AIM: How can we explain the
behavior of gases?
DO NOW:
1. Take out reference table, and pen/pencil 2. Answer
the following
2. Questions using heat
calculations review book????
HEAT CALCULATION PRACTICE
KINETIC MOLECULAR THEORY
 Scientists construct models to explain the behavior of
substances
The Kinetic Molecular Theory (KMT) is a model that is used
to explain the behavior of gases
It explains and/or describes the relationships among several
variables used to analyze gases
The main variables that we discuss during this topic are
pressure (P), volume (V), and temperature (T)
Kinetic Molecular Theory
 Kinetic Molecular
Theory: is a model or
theory that is used to
explain the behavior of
gases
Kinetic Molecular Theory
Major Ideas and Assumptions of KMT
1. Gases contain particles that are in constant, random,
straight-line motion.
2. Gas molecules collide with each other and the walls of their
container (exerting pressure). The collisions are considered
perfectly elastic ( the particles do not lose energy when they
collide)
Kinetic Molecular Theory
Major Ideas and Assumptions of KMT
3. The particles of a gas sample are so small compared to the
overall volume the sample occupies. Therefore, the
particles’ individual volumes can be ignored (they have
negligible volume)
4. Gas particles do not attract each other at all (do not exhibit
intermolecular forces)
AIM: HOW CAN WE EXPLAIN THE BEHAVIOR
OF GASES - IDEAL GAS BEHAVIOR
 What does the kinetic molecular theory describe the
behavior of: solids, liquids or gases?
 What variables will be used during this topic?
 What is temperature measured in?
 List two ideas/assumptions from the KMT
 Explain in terms of intermolecular forces why gas particles
will completely fill up any container which it is placed in.
IDEAL GAS BEHAVIOR – how to get real
gases to behave like ideal gases…
- Use Hydrogen and Helium in experiments (they behave most ideally,
they have smallest volume and weakest attraction)
- Do experiments under condition of high Temperature and low
Pressure (think Ideal vacation!) – PLIGHT!!!
PRESSURE
LOW
IDEAL
GAS
HIGH
TEMPERATURE
IDEAL GAS BEHAVIOR – Ideal vs. Real
IDEAL
REAL
1. No volume
1. Has volume
2. Continuous random straight line motion
2. Not always
3. No energy loss
3. Some energy loss
4. No attractive forces
4. Has attractive forces (weak)
GAS BEHAVIOR – Avogadros Hypothesis
Equal volumes of gases at the same
temperature and pressure have the same
number of molecules
http://www.youtube.com/watch?v=qf60wIUJdN0
AIM: How can we explain the
relationships between P,T, & V?
 The Gas Laws are relationships between temperature, pressure,
and volume of a gas. Gas Law equations are used to determine
what affect changing one of those variable will have on any of the
others.
Gas laws- relationships AMONG
VARIABLEs : Pv & t
• Gases are unique in that they do not have a
definite volume (solids and liquids do!)
• That means we change the conditions at which
a sample of gas exists (such as pressure around
it or the temperature of the gas itself), we can
change the volume of the gas sample
Gas laws- relationships AMONG
VARIABLEs : Pv & t
• In order to understand how the variables affect
each other we need to keep one of the variables
constant
• Important assumption  the number of
molecules is being kept constant as well (we
have a closed container during the experiments)
AIM: How can we explain the relationships
between P,T, & V? - PTV trick
P T V
AIM: How can we explain the
relationships between P,T, & V?
Charles Law
Boyles Law
Gay – Lussacs Law
CHARLES LAW http://www.youtube.com/watch?v=iSK5YlsMv4c
http://www.youtube.com/watch?v=GcCmalmLTiU
Experiment # 1: Relationship between
temperature and volume
Variable kept constant:
Describe what happened:
Draw a graph that shows the relationship:
Boyles LAW - http://www.youtube.com/watch?v=N5xft2fIqQU
Experiment # 2: Relationship between pressure
and volume
Variable kept constant:
Describe what happened:
Draw a graph that shows the relationship:
http://www.absorblearning.com/media/item.action;jsessionid=1AE3B6780572DAA30
A7E9A26C690B744?quick=10k
Gay-Lussac's law http://www.youtube.com/watch?v=ZDFF4HeuAAg
Experiment # 3 Relationship between pressure and
temperature
Variable kept constant:
Describe what happened:
Draw a graph that shows the relationship:
AIM: How can we explain the relationships
between P,T, & V? - Combined Gas Law
Equation
To solve gas law problems follow the steps:
 Make a data table (Temp ALWAYS in Kelvin)
P1
P2
V1
V2
T1
T2
AIM: How can we explain the relationships
between P,T, & V? - Combined Gas Law
Equation
 Write down the gas law equation
 Circle the variable you are trying to solve for, and use basic
algebra to rearrange the equation
 Eliminate anything that is held constant
 Substitute the numbers in the rearranged equation
 Round off your answer using sig figs!
AIM: How can we explain the relationships
between P,T, & V? - Combined Gas Law
Equation
1.
A 2.00 L sample of gas at STP is heated to 500. K and
compress to 200.kPa. What is the new volume of the gas?
1.
A 2.00 L sample of gas at 1.00 atm and 300. K is heated to
500. K and compressed to a volume of 1.00 L. What is the
new pressure of the gas?
AIM: How can we explain the relationships
between P,T, & V? - Combined Gas Law
Equation
3.
A 2.00 L sample of gas at 300. K and a pressure of 80.0 kPa is
placed into a 1.00 L container at a pressure of 240. kPa.
What is the new temperature of the gas?
4.
A sample of gas occupies a volume of 2.00 L at STP. If the
pressure is increased to 2.00 atm att constant temperature,
what is the new volume of the gas?
AIM: How can we explain the relationships
between P,T, & V? - Combined Gas Law
Equation
5.
A sample of gas occupies a volume of 5.00 L at 300. K. If the
temperature is doubled under constant pressure, what will
the new volume of the gas be?
6.
A 10.0 L sample of gas in a rigid container at 1.00 atm and
200. K is heated to 800. K. Assuming that the volume
remains constant, what s the new pressure of the gas?
AIM: How can we explain the relationships
between P,T, & V? - Ideal Gas Law Equation
 The pressure and volume of a gas are proportional to the
number of moles of gas and the Kelvin temperature (n =
number of moles, R = constant 0.0821 atm-L/mol-K)
 Mole – unit of measurement like a dozen represents 12 eggs
 Since one mole of gas exerts a pressure of 1 atm and occupies
a volume of 22.4 L at 273 K- we can derive the value of R from
this.
AIM: How can we explain the relationships
between P,T, & V? - Ideal Gas Law Equation
Examples:
1.
What is the pressure exerted by 3.00 moles of gas at a
temperature of 300. K in a 4.00 L container?
1.
What is the volume of a sample of gas if 5.00 moles if it
exerts a pressure of 0.500 atm at 200. K?
AIM: How can we explain the relationships
between P,T, & V? - Ideal Gas Law Equation
Examples:
3.
A sample of gas is contained in a cylinder with a volume of
10.0 L. At what temperature will 2.50 moles of contained
gas exert 20.0 atm of pressure on the container?
4.
A sample of gas contained in a cylinder of 5.00 L exerts a
pressure of 3.00 atm at 300. K. How many moles of gas are
trapped in the cylinder?
PRESSURE
 PRESSURE: force exerted over an area
Units: atmospheres (atm), kilopascals (kPa), millimeters of mercury (mmHg)
1 atm = 101.3 kPa = 760 mmHg
Conversion Examples:
2.5 atm to kPa
123.4 kpa to atm
Vapor Pressure
VAPOR PRESSURE: the pressure exerted by a liquid’s vapor
in a sealed container at a vapor-liquid equilibrium at a given
temperature; it is not dependent on the mass or volume of
the liquid. The vapor pressure of a liquid can be found on
Reference Table H. The stronger the attractive force
between liquid molecules, the lower the vapor pressure is.
Substances with high vapor pressure evaporate quickly, these
substances are called volatile
Boiling Point
 BOILING POINT: the temperature at which a liquid’s vapor pressure
equals the pressure exerted on the liquid by outside forces. Use Reference
Table H to determine a liquid’s boiling point. Boiling point increases as
exerted pressure is increased.
NORMAL BOILING POINT: the boiling point of a liquid under a pressure of
1.00 atmospheres
** substances with higher boiling points have stronger intermolecular
forces, holding the molecules closer together, requiring more energy to
overcome the attractive forces **
How to Use Table H
How to Use Table H
AIM: How can we explain the behavior
of gases in terms of pressure? – Daltons
Law of Partial Pressure
Daltons Law of Partial Pressures: The total pressure exerted by a mixture of
gases is equal to the sum of the pressures exerted by each of the gases in
the mixture
PTOTAL = PA + PB + PC + …..
AIM: How can we explain the behavior
of gases in terms of pressure? – Daltons
Law of Partial Pressure
Examples:
 What is the total pressure of a mixtues of O2 (g), N2 (g) and
NH3 (g) if the pressure of the O2 (g) is 20. kPa, N2 (g) is 60.
kPa and the NH3 (g) is 15 kPa?
 A mixture of 1 mole of O2 and 2 moles of N2 exerts a
pressure of 150 kPa. What is the partial pressure of each gas?
AIM: How can we explain the behavior of
gases in terms of pressure? – Grahams Law of
Effusion and Diffusion
 Diffusion: used to describe the mixing of gases; the rate of
diffusion is the rate of mixing (picture below)
AIM: How can we explain the behavior of
gases in terms of pressure? – Grahams Law of
Effusion and Diffusion
 Effusion: describes the passage of gas through a tiny orifice
into an evacuated chamber; the rate of effusion measures
the speed at which the gas is transferred (picture to the right)
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Classification of matter
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Classification of matter
 SUBSTANCES (elements and compounds): are all
HOMOGENEOUS (containing the same composition of material
throughout the sample)
 Elements: substances that cannot be broken down by chemical
change (symbols are on Periodic Table) Ex. N (nitrogen) Ni (nickel)
 Compounds: substances that are made up of elements chemically
bonded together, can be decomposed by chemical means. (Two or
more element symbols combined) Ex. NaCl (sodium and chlorine)
constant composition
 MIXTURES: combination of substances that are not chemically
combined together, and can be broken down by physical means
ratio will vary
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Classification of matter
 MIXTURES: combination of substances that are not
chemically combined together, and can be broken down by
physical means ratio will vary
 Homogeneous Mixture: (SOLUTION) uniform composition Ex:
salt water
 Heterogeneous Mixture: non uniform composition Ex: sand
water
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Particle Diagrams
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Particle Diagrams
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Separation of Mixtures
Filtration: separate solid
from liquid or liquid
from gas, or two
immiscible (not capable of
mixing) liquids
Distillation: separate two
miscible (capable of mixing)
liquids, solids and liquids in
homogeneous mixtures,
separate out gases
AIM: What kinds of matter are there, and how can you turn
one form of matter into another form? – Separation of
Mixtures
 Chromatography: used to separate the components of a
mixture based on attraction for substances not in the mixture
(gas chromatography, paper chromatography)
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Physical Properties and Changes
 Physical Changes: changes that change only the appearance
of the substance, not its chemical identity
 Physical Properties: properties that can be observed though
physical change
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Physical Properties and Changes
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Chemical Properties and Changes
 Chemical Changes: changes that result in changing the
chemical composition of a substance, can be reversed by
another chemical change – results in a new substances being
formed
 Chemical Properties: properties that can only be observed
through a chemical change
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Law of Conservation
MATTER CANNOT BE
CREATED NOR
DESTROYED, BUT CAN
CHANGE FROM ONE
FORM TO ANOTHER
AIM: What kinds of matter are there, and how can
you turn one form of matter into another form? –
Law of Conservation
Examples:
1.
If 40 grams of substance A are reacted with 20 grams of substance B
to form substance C, what will the mass of substance C be?
2.
35 grams of liquid water are evaporated off in a closed container. How
many grams of water vapor will there be when the process is done?
3.
Magnesium metal is reacted with oxygen to form magnesium oxide.
How will the mass of the magnesium oxide be compared to the
combined masses of the magnesium metal and the oxygen that
formed it?