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UNIT 1: MATTER AND ENERGY (Review Book Topic 4)
HONORS CHEMISTRY – MS. ARGENZIO
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?
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
What is matter??? Anything that:
Has mass Takes up space
Lets Review……
STATES OF MATTER
There are 3 states of matter
SOLIDSParticles tightly packed togetherParticle Movement type: vibrateHas definite shapeHas definite volume
Examples
LIQUIDSParticles are moderately packed togetherParticle movement: Vibrate and RotateNo definite shape, Takes the shape of its containerHas Definite Volume
Examples
Particles are loosely packedParticle movement: Vibrate, Rotate & bounce off containerHas No Definite ShapeHas No Definite Volume
GAS (vapor)
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 addedAverage KE of particles remains the same
Particles absorb heat as Potential Energy
FREEZING
change from LIQUID to SOLID Heat is removed (EXOTHERMIC)Molecules get closerSolidification no temp change P.E. decreases
HEAT OF FUSIONAmount of heat needed to melt a solid under normal conditionsFreezing requires same amount of heat as melting (it is released instead of absorbed) Table T for equation: q = mHf
EVAPORATION
LIQUID to GASHeat is absorbedMolecules spread out Vaporization No change in temp gain P.E.
CONDENSATION
GAS to LIQUID Heat is removedMolecules get closer
HEAT OF VAPORIZATIONAmount of heat needed to convert a liquid to gas under normal conditionsCondensation 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?
2. What is happening at the two plateaus on the graph?
3. Why doesn’t the kinetic energy change at these spots?
4. The melting point of water occurs at the same temperature as the _________________________ point of water.
5. What other phase changes happen at the same temperature?
Heating the water
Phase change
Temperature doesn’t change
freezing
Condensation and Evaporation
Energy Changes Associated with Phase Changes
Energy: the ability to do work or produce heatTypes: Light energy ( radio waves, microwaves, etc.), heat,
mechanical, chemical, nuclear etc.
Potential energy: Stored energyEx) 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 TheoryMajor 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 TheoryMajor 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 IDEALGASHIGHTEMPERATURE
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=1AE3B6780572DAA30A7E9A26C690B744?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?
2. 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?
2. 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
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? – Separation of Mixtures
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? – Physical 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? – Chemical Properties and Changes
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?
AIM: What kinds of matter are there, and how can you turn one form of matter into another form? – Law of Conservation
