Question of the Day Day 3 11-29 liquids gases ______ and ______ are both fluids, but gases can only flow if …

Reviewish Intramolecular forces are bonds inside of molecules that hold different atoms together (like the force between a carbon and oxygen atom in CO2).   List as many intramolecular forces as you can think of:

Unit 8: Intermolecular Forces I. Forces Determine Phase A. Intramolecular Forces 1. Intramolecular forces are forces _______ molecules. 2. Hold ______ together; _________ and ______ bonds 3. Determine _____ __ ___________ within nonpolar atoms polar type of compound

Unit 8: Intermolecular Forces 4. Dependent upon ________________ differences between bonded atoms 5. Contribute to phase determination since intramolecular bonds determine ________ B. Intermolecular forces 1. Intermolecular forces are forces ________ _________ molecules. electronegativity polarity between different

Unit 8: Intermolecular Forces 2. Hold _________ __________ together 3. Determine phase; type of force depends upon ________ of molecules different molecules polarity

Unit 8: Intermolecular Forces C. Relative Strengths of Forces by Phase 1. Strongest forces found in ______; weakest forces found in ______ a. melting points - ________ with an ________ in the strengths of intermolecular forces b. boiling points – the _______ the intermolecular forces the _______ the boiling point solids gases increase increase higher higher

Unit 8: Intermolecular Forces C. Relative Strengths of Forces by Phase 2. Consider several properties of the different phases as evidence of force strength: a. Entropy - solids  organization comes from strong bonds  ionic crystals; gases  weak bonds allow them to be free

Unit 8: Intermolecular Forces b. Ability to hold shape or volume c. Diffusion / dissolving rates d. Fluidity - solids  strong bonds  rigid shapes; liquids  fairly strong bonds  flexible shapes; gases  weak bonds  variabale shape and volume - solids  slow  strong bonds hold particles together; gases  fastest  weaker bonds allow freedom to mingle Gases flow? - solids  bonds are too strong to allow for flow; liquids + gases  can flow since attractions are weaker

Unit 8: Intermolecular Forces e. Smell f. Reaction rates - solids  toughest to smell  strong bonds hold particles together making it harder for them to escape and fly into your nose - gases  fastest reaction rates  weakest bonds give them the least obstacles to overcome with activation energy

Q of the Day Locate your Chapter # 4 Test. Calculate and record your % grade. Did you meet your goal? Why or why not. Study (preparation) Plan for next test? Record your new goal: - If you did not meet your goal it stays the same - If you did meet your goal – improve by one percentage points Day 5 12-1

Homework and Such Read section 8.4 and answer #s 31-38 on page 253 Due Thursday 12-1 Postlab Questions - Hydrogen

Review List the states of matter in order of increasing:   Diffusion rate Entropy Reaction rate Intermolecular attraction

Unit 8: Intermolecular Forces II. Types of Intermolecular Forces A. Ion-Dipole Forces 1. Ion-dipole forces exist between an ___ and a ______ __________ ion polar molecule

Unit 8: Intermolecular Forces 2. Diagram an example: NaCl dissolved in H2O

Unit 8: Intermolecular Forces B. Dipole-Dipole Forces 1. Dipole-dipole forces exist between ______ __________ 2. The dipole moment is the measure of the __________ of the + & - charges. a. Higher value indicates ________ polarity polar molecules separation greater

Unit 8: Intermolecular Forces b. Lower value indicates ______ polarity 3. Diagram an example: CH3OH mixed with CH3Cl lesser

Unit 8: Intermolecular Forces D. Induced dipole - ___________________ ____________________________________ 1. Exists in a molecule that is normally _________. 2. Induced dipoles are ___________. temporary dipole in a nonpolar molecule usually caused by brining it near a polar molecule nonpolar temporary Stopped CP2 12-1

Unit 8: Intermolecular Forces D. Induced dipole - ___________________ ____________________________________ temporary dipole in a nonpolar molecule usually caused by brining it near a polar molecule Soluble O2 Ex.– (+) pole of water temporarily attracts the elecs. of O2 H electrons O O O (-) (+) (-) (+) H

Unit 8: Intermolecular Forces C. London Dispersion Forces 1. London dispersion forces exist between _________ _________ and are found in ____ ___________ 2. Induced dipoles and instantaneous dipoles arise when the ________ clouds of atoms or molecules are _________ by an outside influence such as a collision. nonpolar particles All substances electron distorted

Unit 8: Intermolecular Forces ease 3. Polarizability is the _____ in distorting or “squashing” the electron cloud. 4. The _________ of the dispersion forces depends upon several factors ________ of _________ - more electrons = more polarizable (easier to distort)  stronger dispersion forces strength number electrons He vs. Ne

Unit 8: Intermolecular Forces 4. The _________ of the dispersion forces depends upon several factors _____ or ____ - more mass = more polarizable (easier to distort)  stronger dispersion forces ______ strength mass size CH4 vs. C6H14 shape (page 388)

Unit 8: Intermolecular Forces 5. Diagram an example: He mixed with Ne Normal As Induced Dipoles

Click and Clack

Warm-up # 3 1. In the table above the boiling points increase with _________________ molecular weight because the London dispersion forces are _________________.   2. Which of the following substances is most likely to exist as a gas at room temperature and normal atmospheric pressure: P4O10, Cl2, AgCl, I2? Noble Gas Boiling Point (K) He 4.6 Ne 27.3 Ar 87.5 Kr 120.9 Xe 166.1

Unit 8: Intermolecular Forces D. Hydrogen Bonding 1. Hydrogen bonding is the attraction of an atom of _________ from one molecule to an atom with a high ________________ in another molecule, especially __, __, & __. hydrogen electronegativity F O N

Unit 8: Intermolecular Forces 2. Hydrogen bonds affect compound characteristics such as _____________ _________________________________ 3. Diagram an example: H2O mixed with NH3 and HF (see also p 390) boiling point, phase at room temp., shape (DNA), density  see C and H p 391

No Warm-up 3-11 Get out your homework # 2!!! 

Unit 8: Intermolecular Forces E. van der Waals Forces is an umbrella term for the intermolecular forces _________________, ____________, and __________________. F. How do the intermolecular forces compare in strength? london dispersion dipole-dipole hydrogen bonding london < dip.-dip. < H-bond < ion-dip. < ion-ion (for solids)

Unit 8: Intermolecular Forces III. Properties of Liquids A. Viscosity is a liquid’s ____________ to _____. 1. Higher viscosity indicates _____________, ___________, & _______________ resistance flow “thickness” slow flow Strong bonds

Unit 8: Intermolecular Forces 2. Lower viscosity indicates ____________, __________, & _____________ 3. Temperature affects viscosity. a. How? b. Why? “thinness” fast flow weak bonds - T up, KE up, movement/flow up - T up, viscosity down,

Online Review Activity http://wps.prenhall.com/esm_brown_chemistry_9/2/660/169060.cw/index.html Homework # 1 – 10 correct

3-15 Warm-up # 4 1. Which liquid should be more viscous at room temperature honey or rubbing alcohol?   2. What if the honey is cooled by 10 degrees and the rubbing alcohol is heated by 10 degrees? 3. What intermolecular forces exist for NH3? Put them in increasing order of strength.

Quick Talk Intermolecular force Viscosity Ion-dipole force Induced dipole Hydrogen bonding London-dispersion force

Unit 8: Intermolecular Forces B. Surface Tension 1. Surface tension = net ________ force on the particles at a _________ surface a. “Skin” is visible as molecules are ________ __________. b. Creates ___________ shape and less _________ ______ inward liquid’s packed together spherical surface area

Unit 8: Intermolecular Forces 2. Capillary action is a liquid’s rising in a _________ ______ until cohesive and adhesive forces _________. Examples: narrow tube balance

Unit 8: Intermolecular Forces 3. Meniscus shape depends on strengths of cohesion versus adhesion. a. H2O shape indicates stronger ___________ and weaker __________ b. Hg  shape indicates stronger __________ and weaker ___________ cohesion  adhesion  adhesion cohesion cohesion adhesion water sticking to water water sticking to another polar substance

Unit 8: Intermolecular Forces IV. Vapor Pressure A. Vapor pressure is the pressure just above the _________ of a _______ or ______ as the particles escape into the air. B. Volatility 1. Liquids that are volatile ___________ easily. surface liquid solid evaporate

Unit 8: Intermolecular Forces 2. Volatility depends on _________________, ________________________, vapor pressure Higher vapor pressure = MORE volatile intermolecular forces Weaker intermolecular forces of attraction = MORE volatile

Unit 8: Intermolecular Forces 2. Volatility depends on ______________, and ______________. C. Boiling 1. ______ ___________ = __________ __________ size / weight temperature vapor pressure external pressure

Unit 8: Intermolecular Forces C. Boiling 2. What obstacles must a water molecule overcome in order to boil? Intermolecular forces, especially H bonds (love of neighbors & family) Surface tension (surface sentinels  who goes there?) Pressure from outside (kept down by “the Man”)

Warmup # 5 How could we get water to boil withOUT changing temperature? Which is more volatile water or acetone? Explain reasoning! acetone =

Unit 8: Intermolecular Forces

Unit 8: Intermolecular Forces Critical temperature – the highest temp. at which a substance can exist as a liquid (greater intermolecular attractive forces = higher critical temp.  substance would rather be liquid) critical pressure – pressure necessary to achieve liquid at critical temp. Triple point – temp. at which solid, liquid, and gas phases coexist in equilibrium

Homework and Such Reading: pages 382-395, 399-404 Homework # 3 = Ch 11 P 417 19-22, 33, 34, 36 – Wednesday 3-17 http://wps.prenhall.com/esm_brown_chemistry_9/2/660/169060.cw/index.html Homework # 2 – 11 correct

* During a phase change, temperature does NOT change (slope = 0) AS WE HEAT A SOLID!

NO warm-up: Take everything off your desk except writing utensil – unannounced quiz 3-17

Hand in Hwk Reading: pages 382-395, 399-404 Homework # 3 = Ch 11 P 417 19-22, 33, 34, 36 – Wednesday 3-17

Read the half sheet (Car Talk) Warm-up # 6: Read the half sheet (Car Talk) What would you tell Wil? – write on back 3-18

Unit # 8 Test = Tuesday 3-23 Lab Talk

Online Review Activity http://wps.prenhall.com/esm_brown_chemistry_9/2/660/169060.cw/index.html Homework # 3 – 8 correct

Warmup # 1 There is a bottle with two liquids on my desk (a blue liquid and a clear liquid), tell me everything you possibly can about the liquids and any intermolecular forces that may or may not be present.

Warmup # 2 What would you write back?

Warmup # 3 See half sheet, there are two!!!

H O H

melting is in equilibrium with freezing

Temperature (˚C) 1.5 atms. 1.0 atms. 0.5 atms. 0.5 atms. 10 20 30 40 50 60 70 80 90 Temperature (˚C)