Warm-up: Atomic size is one of the many trends of the Periodic Table. Describe one reason atomic size many vary between the elements on the Periodic Table. Arrange these elements in descending order: Al, Mg, P, Si, Na, S Explain why you chose this order.

Characteristics of Solids, Liquids & Gases Sort characteristics of solids, liquids and gases into 3 columns (use workbook page 1 if needed) Solid Liquid Gas

Most substances, like water, can exist in all three states. An iceberg is made of water in solid form. This glass contains liquid water. A cloud is made of water vapor, a type of gas.

WHAT ARE THE CHANGES OF STATE? Which are endothermic? Which are exothermic? GAS Deposition Boiling / Evaporation Sublimation Condensation Freezing SOLID LIQUID Melting

Changing States (Phase changes) Where on the picture would we place: Melting Point? Boiling Point? Condensing Point? Freezing Point? Increase Thermal Energy (Heat up) Solid Liquid Gas Decrease Thermal Energy (Cool off)

Melting point Melting - change from solid to liquid Melting point - SPECIFIC temperature when melting occurs. Each pure substance has a SPECIFIC melting point. Examples: M.P. of Water = 0°C (32°F) M.P. of Nitrogen = -209.9 °C (-345.81998 °F) M.P. of Silver = 961.93 °C (1763.474 °F) M.P. of Carbon = 3500.0 °C (6332.0 °F)

Melting Point Solid How does melting occur? Particles of a solid vibrate so fast that they break free from their fixed positions. Increasing Thermal Energy Solid Liquid Melting point

Vaporization Vaporization – change from liquid to gas Vaporization happens when particles in a liquid gain enough energy to form a gas. Increasing Thermal Energy Gas Liquid Boiling point

Two Kinds of Vaporization Evaporation – vaporization that takes place only on the surface of the liquid Boiling – when a liquid changes to a gas BELOW its surface as well as above.

Boiling Point Boiling Point – temperature at which a liquid boils Each pure substance has a SPECIFIC boiling point. Examples: B.P. of Water = 100°C (212°F) B.P. of Nitrogen = -195.79 °C (-320.42 °F) B.P. of Silver = 2162 °C (3924 °F) B.P. of Carbon = 4027 °C (7281 °F)

Heating and Cooling Curves of a Substance Representing MP, BP, CP, FP Energy (heat) added Energy (heat) released:

Intermolecular Forces Forces between molecules (compounds) which helps determine whether a substance is a solid or liquid Gases have little/no intermolecular forces

Energy requirements for water Three formulas : specific heat Q = mCp∆T Energy requirements for water Three formulas : specific heat Q = mCp∆T heat of fusion Q= mHf heat of vaporization Q= mHv Heating Cooling Energy (heat) added Energy (heat) released:

Energy calculations related heating or cooling specific substances Specific heat (Cp) Latent heat Heat of fusion (Hf) Heat of vaporization (Hv) Use reference tables – values for each pure substance

Heat calculations – 3 formulas Specific heat = heat required to raise the temperature of 1 gram of substance 1 °C Formula: Q = mCp∆T Specific heat Specific for each pure substance Use reference tables

Heat calculations – 3 formulas Heat of fusion - Amount of heat added to melt a substance Amount of heat released to freeze a substance Formula Q= mHf Specific for each pure substance Use reference tables

Heat calculations – 3 formulas Heat of vaporization- Amount of heat added to boil a substance Amount of heat released to condense a substance Formula Q= mHv Specific for each pure substance Use reference tables

Heat energy In a heat calculation problem, if the problem asks about melting/freezing you would multiply the mass times _____________________. heat of fusion heat of vaporization or specific heat In a heat calculation problem, if the problem asks about vaporizing/condensing of steam, you would multiply the mass times ________. Heat of fusion Heat of vaporization Specific heat In a heat calculation problem, if the problem asks about a change in temperature, you would multiply the mass times ___________________ times the change in temperature. Heat of fusion Heat of vaporization Specific heat  

Thermochemistry Problems related to water How much heat is required to raise the temperature of 789 g of water from 25oC to 70oC?   2. How much heat is released when 432 g of water cools from 71oC to 18oC? 3. How many joules of heat are given off when 5.9 g of steam cools from 175oC to 125oC?

4. How many joules does it take to melt 35 g of ice at 0oC? 5. How much heat is released when 85 g of steam condense to liquid water?   6. How much heat is necessary to raise the temperature of 25 g of water from 10 oC to 60 oC? 7. How much heat is given off when 50 g of water at 0oC freezes?

What factors impact change? Intermolecular forces Energy Conditions: T, P, V, amount,

Phase Diagrams: What is added to this diagram? Why?

Phase diagrams http://www.youtube.com/watch?v=fLOPaJ8lcr8&feature=endscreen&NR=1

A = B= C= D= For Water T °C 200 °C -2°C 100 °C -2 °C 30°C P - atm Phase Liquid Vapor A = B= C= D=

PHET States of Matter http://phet.colorado.edu/en/simulation/states-of-matter

Review: Interpreting Phase Diagrams Phase Diagrams. Use the phase diagram for water below to answer the following questions. Review: Interpreting Phase Diagrams What is the state of water at 2 atm and 50 C? What phase change will occur if the temperature is lowered from 80C to -5C at 1 atm? You have ice at -10C and 1 atm. What could you do in order cause the ice to sublime?

Interpreting a Phase Diagram of Water at varying pressures Example: 100 atm

1) What is the normal melting point of this substance 1) What is the normal melting point of this substance? ________ 3) What is the normal boiling point of this substance? ________ 4) What is the normal freezing point of this substance? ________ 5) If I had a quantity of this substance at a pressure of 1.25 atm and a temperature of 00 C and heated it until the temperature was 7500 C, what phase transition(s) would occur? At what pressure(s) would they occur? 6) At what temperature do the gas and liquid phases become indistinguishable from each other? ________ 7) If I had a quantity of this substance at a pressure of 0.25 atm and a temperature of -1000 C, what phase change(s) would occur if I increased the pressure to 1.00 atm? At what temperature(s) would they occur?

Water: Connecting Phase Diagram and Heating Curve

Vapor Pressure – Physical Equilibrium The vapor pressure is the pressure measured when there is an equilibrium between the gas and liquid phases. The rates of condensation and vaporization are equal.

Vapor pressure http://www.chem.purdue.edu/gchelp/liquids/vpress.html Discovery Ed video

Resources for S, L, G http://www.kentchemistry.com/links/Matter/HeatingCurve.htm http://www.middleschoolchemistry.com/

How does the chemical composition of a substance impact whether it is a gas, liquid or solid at room temperature?

Overview: Factors that Impact State of Matter Type of compound – Ionic, Covalent, Metallic Intermolecular Forces, impacted by Shape Size Polarity

Intermolecular Forces Attractive forces between molecules Not between individual atoms Much weaker than the bonds within a molecule Intramolecular bonds form between 2 atoms in a molecule/compound _________ , _________, ________ Can determine the state of matter by the number and type of these forces Lots of forces= liquid Lots and lots = solid

What causes these intermolecular forces? Opposites attract: In chemistry this means: How do these attraction between molecules form? Polarity (partial polarity) Shape Size

Intermolecular Forces Three Types Hydrogen Dipole – dipole London Dispersion (Van der Waals) Based on weak attraction between molecules partial negative – partial positive

Let us review – covalent bonds Intramolecular bond Type of atoms in covalent bond Electronegativity Difference Sharing valence electrons to form bonds Some share equally = non-polar covalent bonds Some share unequally = polar covalent bonds

Electronegativity Differences Review Electronegativity Differences = ∆EN Covalent bonds Ionic Bonds ∆ O ∆ 3.2 ∆ 1.7 Increasing polar (+ side and – side) characteristics

Review

Electronegativity Difference Review The electronegativity difference must be equal to or less than _______. It is a polar covalent bond if the difference is between __________. It is a non-polar covalent bond if the difference is between ___________.

Non-Polar Covalent Bond ∆EN= 0 – 0.3 Review Non-Polar Covalent Bond ∆EN= 0 – 0.3 The Electron pair that makes up the bond is shared evenly.

Non-Polar Covalent Bond Review

Polar Covalent Bond Review

Review Polar Covalent Bond

Polar Covalent Bond ∆EN = 0.4 – 1.7 Review The electron pair that makes up the bond is closer to the element that has the higher electronegativity.

Intermolecular Forces Three Types Hydrogen Dipole – dipole London Dispersion (Van der Waals) Based on weak attraction between molecules partial negative – partial positive

Types of Intermolecular Forces Strongest intermolecular force Hydrogen “bond” (~ 10% of a covalent bond) Molecule must be polar (+ and – sides) H in one molecule is attracted to the N,O,F of another molecule Hydrogen Bond - bad choice of words – an attractive force , not a bond

Hydrogen “bonds”: attraction between H with N, O, F Hydrogen bonds between water molecules. Hydrogen bonds give unique properties to water.

Types of Intermolecular Forces Other intermolecular forces Dipole-dipole – all polar molecules (weaker) London dispersion forces – all molecules (weakest)

Dipole-dipole Based on polarity of molecules Found with polar covalent compounds Use with elements other than H attracted to N, O or F

London Dispersion Weakest Temporary polarity Based on movement of the electrons around the nucleus Impacts all molecules – non-polar and polar

Factors that impact the state of matter Intermolecular forces How do these attraction between molecules form? Polarity (partial polarity) Shape Size

Polarity of Water http://ed.ted.com/lessons/how-polarity-makes-water-behave-strangely-christina-kleinberg#watch http://www.middleschoolchemistry.com/multimedia/chapter5/lesson1#polar_water_molecule Short Tutorial with animations of polarity

Polarity http://phet.colorado.edu/en/simulation/molecule-polarity Use real molecules tab Molecular dipoles Electronegativity Electron density or electrostatic potential Note: VSEPR – valence shell electron pair repulsion impacts shape

Shapes of Molecules http://ed.ted.com/lessons/what-is-the-shape-of-a-molecule-george-zaidan-and-charles-morton PHET simulation (?) http://phet.colorado.edu/en/simulation/molecule-shapes

Predicting the Shape: VSEPR Valence shell electron pair repulsion VSEPR theory Non-bonding pairs of electrons (lone pairs) will push away (repel) from each other Use Lewis structures to model VSEPR http://www.green-planet-solar-energy.com/lewis-dot-structure.html

VSEPR: Lewis dot structure shows the pulling away of electron pairs Water Ammonia

Methane: CH₄

Ammonia: NH₃

Water: H₂0

Why is water unique? Why does ice float on water? https://ed.ted.com/lessons/why-does-ice-float-in-water-george-zaidan-and-charles-morton Hydrogen bonds -

Review: Energy in chemical reactions Exothermic chemical reaction

Review: Energy in chemical reactions Endothermic chemical reaction