Liquids and solids slides
Upcoming SlideShare
Loading in...5
×
 

Liquids and solids slides

on

  • 196 views

Liquids and Solids

Liquids and Solids

Statistics

Views

Total Views
196
Views on SlideShare
196
Embed Views
0

Actions

Likes
0
Downloads
3
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Liquids and solids slides Liquids and solids slides Document Transcript

  • AP Chemistry Rapid Learning Series - 17 Rapid Learning Center Chemistry :: Biology :: Physics :: Math Rapid Learning Center Presents … p g Teach Yourself AP Chemistry Visually in 24 Hours 1/64 http://www.RapidLearningCenter.com Liquids and Solids AP Ch i t R id Learning Series Chemistry Rapid L i S i 2/64 Wayne Huang, PhD Kelly Deters, PhD Russell Dahl, PhD Elizabeth James, PhD Debbie Bilyen, M.A. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com Rapid Learning Center www.RapidLearningCenter.com/ © Rapid Learning Inc. All rights reserved. 1
  • AP Chemistry Rapid Learning Series - 17 Learning Objectives By completing this tutorial you will learn… What intermolecular forces are Properties of liquids P ti f li id How vapor pressure is affected by intermolecular forces and temperature How solids are structured How matter changes states The energy changes during a phase change 3/64 Concept Map Previous content Chemistry New content Studies Matter Bonding Structures Has different Have different possibilities of Solids One is States One is Liquids Can change by g y Involves breaking or forming Phase Changes Intermolecular Forces Boiling and melting point determined by Vapor Pressure 4/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 2
  • AP Chemistry Rapid Learning Series - 17 Intermolecular Forces 5/64 Definition: Intra & Intermolecular Intramolecular Forces – Chemical bonds within a molecule. Intermolecular Forces (IMF) – Physical attractions between separate molecules. t l l 6/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 3
  • AP Chemistry Rapid Learning Series - 17 London Dispersion Forces All molecules have London Dispersion Forces. Due to a temporary “ganging up” of electrons on one side of the molecule. Nucleus δ- + - δ+ - + - - Electrons - As the l t A th electrons move around the molecule, they can d th l l th temporarily end up on one side. This results in a portion of the molecule that has a partially negative charge and a portion with a partial positive charge. 7/64 London Dispersion Forces Properties Properties of London Dispersion Forces: Temporary p y The electrons continue g p moving and “spread out” again. Weakest IMF It’s temporary, and therefore weak. All molecules have them All molecules have electrons which can “gain up”. up” The larger the molecule, the larger the force The more electrons in a molecule, the greater the effect of “ganging up”. 8/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 4
  • AP Chemistry Rapid Learning Series - 17 Dipole-Dipole Forces Polar molecules exhibit dipole-dipole forces. Polar molecules have a permanent partial separation of charges. δ+ δ- Polar Molecule e.g. sugar and water The opposite charges on separate polar molecules are attracted to one another. They are not chemical bonds, just physical attractions between opposite charges. 9/64 Ion-Dipole Forces An ion and a polar molecule exhibit ion-dipole forces. Polar molecules have a permanent partial separation of charges. δ+ δ- Polar Molecule + Cation e.g. water and Na+ Ions are attracted to the partially charged regions of a polar molecule. They are not chemical bonds, just physical attractions between opposite charges. 10/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 5
  • AP Chemistry Rapid Learning Series - 17 Dipole Forces Properties Properties of Dipole Forces: Permanent dipoles p Partial separation of g charge within the molecule is permanent. Stronger IMF Although the IMF is not permanent, the ability to form the IMF is. Only polar molecules can exhibit them A permanent dipole (separation of charges) is needed. The stronger the dipole, the stronger the force Stronger dipoles have greater attraction to other charges. 11/64 Hydrogen Bonding Hydrogen bonding is an especially strong case of dipole-dipole forces. Hydrogen atoms contain only 1 proton and 1 electron. - - - O - - H H δ- δ+ When hydrogen is bonded to a very electronegative atom (N, O or F), the separation of charges is very large as there are no other electrons around the hydrogen proton at all. The hydrogen in this extreme dipole can be attracted to the lone pairs on an N, O or F atom on another molecule. 12/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 6
  • AP Chemistry Rapid Learning Series - 17 Hydrogen Bonding Properties Properties of Hydrogen Bonds: Extreme case of dipole forces H has no other electrons, it is very positive when sharing electrons with a very electronegative atom. Strongest IMF Stronger than typical dipole forces Molecules with an H on an N, O or F can hydrogen bond With lone pairs on N, O or F atoms in another molecule 13/64 Intermolecular Forces Summary A summary of the 4 IMF’s: Type of force Happens with Relative strength London Dispersion All molecules Weakest Dipole-dipole Polar molecules Medium Ion dipole Ion-dipole Ion & polar molecule Medium Hydrogen bonding H on an N, O or F with another N, O or F Strongest 14/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 7
  • AP Chemistry Rapid Learning Series - 17 Liquids 15/64 Properties of Liquids Some general properties of liquids: Property Example Definite volume No definite shape Drink pools out when poured on a table. Molecules are free to move past each other A drop of food coloring moves through the liquid over time. Not very compressible 16/64 Pouring a drink into a larger glass doesn’t make more of the drink. A full bottle of water (no air) cannot be compressed. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 8
  • AP Chemistry Rapid Learning Series - 17 Definition: Vapor Pressure Vapor Pressure – Pressure created above a sample by t d b l b particles evaporating from the sample and becoming gas particles. 17/64 Vapor Pressure of a Liquid Solvent particles on the very top layer of the sample can evaporate. Looking down on the top of a solution in a beaker: Side view Gas particles now cause pressure-vapor pressure. 18/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 9
  • AP Chemistry Rapid Learning Series - 17 Definition: Equilibrium Equilibrium – Rate of change equals the rate of the opposite change. Rate forward = Rate reverse 19/64 Vapor Pressure Equilibrium Vapor Pressure equilibrium can be achieved in a closed system. The rate of evaporation of a liquid is constant. constant rate evaporation condensation time As the liquid evaporates, gas particles are formed which can then begin to condense down to the liquid form again. As more gas particles are created, the rate of condensation increases. 20/64 Equilibrium is reached when rate evaporation = rate condensation. © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 10
  • AP Chemistry Rapid Learning Series - 17 Volume of the Liquid and Equilibrium The volume change as equilibrium is established. Liquid volume decreases as initial gas particles are formed. Liquid volume begins to increase as gas particles begin to re-condense. Liquid volume is constant once equilibrium has been reached. It’s less than the initial volume. 21/64 Vapor Pressure and Temperature Solvent particles on the very top layer of the sample can evaporate. In order to evaporate, the particle must have enough energy to break the intermolecular forces connecting it with the other liquid particles. Higher temperature means the average kinetic energy of the molecules is higher. More molecules have the minimum energy needed to vaporize. As temperature increases, vapor pressure increases. 22/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 11
  • AP Chemistry Rapid Learning Series - 17 Solids 23/64 Properties of Solids Some general properties of solids: Property Example Definite volume A solid cannot “grow or shrink” Definite shape Solids cannot spontaneously change shape Molecules are not free to move past each other A dot of ink doesn t travel doesn’t across the top of a desk Not compressible A piece of ice cannot be compressed 24/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 12
  • AP Chemistry Rapid Learning Series - 17 Types of Solids Structures - Part 1 Solids Amorphous Solids Crystalline Solids 25/64 Definition: Amorphous and Crystalline Amorphous Solid – Has a fair amount of disorder in the structure. Crystalline Solid – Has a highly regular, repeating arrangement of particles. 26/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 13
  • AP Chemistry Rapid Learning Series - 17 Amorphous Solids Amorphous solids are still rigid—they are still solid… But they’re p y particles are not trapped in a repeating pp p g pattern as in crystalline solids. An example is glass. The particles are trapped in a position before they have a chance to arrange themselves in a repeating pattern. 27/64 Crystalline Solids Crystalline structures are lattice structures, composed of unit cells. Lattice Overall crystalline structure Unit Cell Smallest repeating unit 28/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 14
  • AP Chemistry Rapid Learning Series - 17 Types of Unit Cells These are the most simple unit cells are: Cubic 8 particles create a cube Body-centered cubic A cube with a particle in the center of the “body” of the cube Face-centered cubic A cube with a particle in the center of each “face” of the cube 29/64 Types of Crystalline Structures 30/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 15
  • AP Chemistry Rapid Learning Series - 17 Types of Solids Structures - the Rest Solids Amorphous Solids Crystalline Solids Atomic Solids Metallic Molecular Solids Ionic Solids Network 31/64 Definition: Atomic Solids Atomic solids – Atoms are the particles in the unit cell. 32/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 16
  • AP Chemistry Rapid Learning Series - 17 Metallic Solids Metallic bonding contains metal atoms packed closely together and bonded to the atom in each direction equally. This is called “closest packing”. packing” The electrons form a large “pool” that are free to move throughout the structure. This allows metals to conduct electricity! 33/64 Network Solids Network solids can be thought of as one giant molecule. Graphite All of the atoms in the network solids are covalently bonded to their neighbors. Examples of network solids include: graphite, diamonds, silica (sand) 34/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 17
  • AP Chemistry Rapid Learning Series - 17 Definition: Molecular Solids Molecular S Solids – Molecules are the particles in the unit cell. 35/64 Molecular Solids Strong covalent forces within the molecule with weaker forces between the molecules. An example of a molecular solid is ice. 36/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 18
  • AP Chemistry Rapid Learning Series - 17 Definition: Ionic Solids Ionic Solids – Structure containing positive and negative ions (cations and anions). 37/64 Binary Ionic Solids Binary ionic solids have a variation of the closest packing structures. The larger ion is packed in the closest packing structure. The smaller ion fits in between the holes created by the larger ion. This minimizes repulsions from like-charged ions. 38/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 19
  • AP Chemistry Rapid Learning Series - 17 Solid Structure Summary Type Unit cell Bonding There is no unit cell Strong intramolecular, S weaker intermolecular Metallic Metal atoms Pool of electrons that are free to move Network Non-metal atoms Covalent bonding throughout Molecular Molecules Covalent within molecule, weaker between Ionic Ions Electrostatic attraction between ions Crysta alline Amorphous 39/64 Solid Structure Properties General properties of the different structure types Type Amorphous Properties Disorder in their structure—no repeating pattern Excellent conductors of heat and electricity, malleable and ductile Network Brittle, poor conductors of heat and electricity Molecular Strong bonds within but weak between (not much energy needed to melt, but a lot to break the chemical bond) Ionic Crystal lline Metallic Stable, high melting points, brittle 40/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 20
  • AP Chemistry Rapid Learning Series - 17 Phase Changes 41/64 Definition: Phase Changes Phase Change – Changes between solids, liquids and gases. sublimation melting Solid boiling Liquid Gas condensing freezing Deposition 42/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 21
  • AP Chemistry Rapid Learning Series - 17 IMF’s and Phase Changes What role to intermolecular forces play in phase changes? Break all IMF’s Break some IMF’s Solid Break rest of IMF’s Liquid Gas Form some IMF’s Form more IMF’s Form IMF’s Breaking IMF’s requires energy Forming IMF’s releases energy 43/64 Definition: Boiling & Melting Points Boiling/Condensation Point – When liquid and gas phases are at equilibrium with one another. Melting/Freezing Point – When solid and liquid are at equilibrium. 44/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 22
  • AP Chemistry Rapid Learning Series - 17 How is Boiling Point Determined? Boiling point is where … vapor pressure = atmospheric pressure. When the vapor pressure of the liquid is great enough to form “bubbles” boiling will occur. Atmospheric pressure Bubbles rise (less dense)…boiling! As temperature increases, the vapor pressure of the liquid increases. increases As vapor pressure within the liquid increases, bubbles can begin to form—pushing against atmospheric pressure. 45/64 How is Melting Point Determined? - 1 Melting point is where… vapor pressure liquid = vapor pressure solid. Temperature 1: Solid vapor pressure > Liquid vapor pressure Molecules escape the solid faster than they escape the liquid. The solid particles escape and join the liquid…but q the liquid molecules aren’t crossing over as fast. After time…end up with all liquid. Temperature is above melting/freezing point. 46/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 23
  • AP Chemistry Rapid Learning Series - 17 How is Melting Point Determined? - 2 Melting point is where… vapor pressure liquid = vapor pressure solid. Temperature 2: Solid vapor pressure < Liquid vapor pressure Molecules escape the liquid faster than th th they escape the solid The liquid particles escape and join the solid…but solid but the solid molecules aren’t crossing over as fast After time…end up with all solid. Temperature is T t i below melting/freezing point 47/64 How is Melting Point Determined? - 3 Melting point is where… vapor pressure liquid = vapor pressure solid. Temperature 3: Solid vapor pressure = Liquid vapor pressure Molecules escape the liquid at the sa e same pace as they escape the solid. The liquid particles escape and join the solid at the same rate the solid particles escape and join the liquid. At equilibrium. Amount of solid and liquid don’t change over h time. Temperature is freezing point. 48/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 24
  • AP Chemistry Rapid Learning Series - 17 Why Do Some Solids Sublime? Why do some substances (such as dry ice) go straight from solid to gas? The intermolecular forces are very weak. The solid particles have enough energy to break all of the IMF’s and go straight to a gas, rather than IMF s gas only breaking some of them and going to a liquid. 49/64 Phase Diagrams - 1 Phase diagrams show what state of matter a substance would exist as at various temperatures and pressures. Phase Diagram for H2O Triple Point All 3 states exist together Pressur (atm) re melting l s 1 0.006 Critical Point Point above which it cannot exist as a liquid boiling sublimation g 0.0099 100 Temperature (°C) 50/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 25
  • AP Chemistry Rapid Learning Series - 17 Phase Diagrams - 2 Phase diagrams show what state of matter a substance would exist as at various temperatures and pressures. Phase Diagram for H2O Pressur (atm) re freezing l s 1 0.006 condensing deposition g 0.0099 100 Temperature (°C) 51/64 Energy of Phase Changes 52/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 26
  • AP Chemistry Rapid Learning Series - 17 Definition: Enthalpy of Fusion Enthalpy of fusion ( fus) – energy py (H gy necessary to break enough IMF’s to turn a solid into a liquid. Energy released when turning a liquid into a solid = - Hfus 53/64 Enthalpy of Fusion Calculations Enthlapy of fusion is used in calculating energy needed to melt or released when freezing. ΔH = m × H fus Example: H = enthalpy (energy) m = mass of sample Hfus = enthalpy of fusion (melting) (use –Hfus for freezing) Find the enthalpy of fusion of water if it takes 4175 J to melt 12.5 g of water 4175 J = (12.5 g ) × H fus Hfus = ? m = 12.5 g H2O ΔH = 4175 J 4175 J = H fus 12.5 g Hfus = 334 J/g 54/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 27
  • AP Chemistry Rapid Learning Series - 17 Definition: Enthalpy of Vaporization Enthalpy of vaporization (Hvap) – py p ( energy necessary to break the rest of the IMF’s and turn a liquid into a gas. Energy released when turning a gas into a liquid = - Hvap 55/64 Enthalpy of Vaporization Calculations Enthalpy of vaporization is used in calculating energy needed to vaporize or released when condensing. ΔH = m × H vap Example: H = enthalpy (energy) th l ( ) m = mass of sample Hvap = enthalpy of vaporization (vaporizing) (use –Hvap for condensation) If the heat of vaporization of water is 2287 J/g, how much energy is released when 15.75 g of water is condensed? Hvap = - 2287 J/g m = 15.75 g H2O ΔH = ? J ΔH = (15.75 g ) × ⎛ − 2287 J ⎜ ⎝ ⎞ g⎟ ⎠ ΔH = -36020 J Energy is released because it’s condensing. 56/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 28
  • AP Chemistry Rapid Learning Series - 17 Solids, Liquids & The AP Exam 57/64 Liquids & Solids in the Exam Common Liquid & Solid problems: Using intermolecular forces to describe properties of compounds d What types of particles are at lattice points in different types of solids The properties different types of solid bonding exhibit 58/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 29
  • AP Chemistry Rapid Learning Series - 17 Multiple Choice Questions Example: Which of the following has the highest melting point? A. B. C. D. E. F Cl Br I Same Melting point is largely determined by intermolecular forces. All of these are pure non-metal elements. They have London Dispersion Forces only. The larger the atom, the more electrons it has, the more London Dispersion Forces it has. The more London Dispersion Forces it has, the more energy is needed to break the IMF’s to melt the solid. Answer: D 59/64 Free Response Questions Example: Use chemical bonding and/or intermolecular forces to explain the following observations: A. At STP, propane (C3H8) is a gas, while octane (C8H18) is ,p p ( g , ( a liquid. B. MgO melts at a much higher temperature than CO2 C. Ethanol (CH3CH2OH) dissolves in water much more easily than ethane (CH3CH3). These are the two sub-questions you can answer after this tutorial. 60/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 30
  • AP Chemistry Rapid Learning Series - 17 Answering Free Response Questions A. At STP, propane (C3H8) is a gas, while octane (C8H18) is a liquid. Both molecules only have London Dispersion Forces. Propane is a larger molecule, therefore it has greater LDF. The greater g , g g the IMF’s, the more energy is needed to melt or boil a substance. C8H18 is larger, and therefore has more IMF’s, and therefore needs more energy to boil—which it hasn’t gotten at STP and is therefore a liquid still. B. MgO melts at a much higher temperature than CO2 MgO is an ionic compound while CO2 is a non-polar covalent compound. MgO has London Dispersion Forces and Ion-Ion interactions while CO2 only has LDF. The more IMF’s, the more energy is needed to pull apart molecules (melt) and therefore, the MgO melts at a higher temperature. 61/64 Learning Summary Matter undergoes phase changes, shown by phase diagrams. Solids and liquids are condensed states of matters that have intermolecular forces. Solids have structures—either t t ith amorphous or crystalline (which can be atomic, molecular or ionic). The energy changes during phase changes are governed by db enthalpies of fusion and vaporization. Liquids d lid Li id and solids have vapor pressures as particles escape to the gas form. 62/64 © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 31
  • AP Chemistry Rapid Learning Series - 17 Congratulations You have successfully completed the core tutorial Liquids and Solids Rapid Learning Center 63/64 Rapid Learning Center Chemistry :: Biology :: Physics :: Math What’s N t Wh t’ Next … Step 1: Concepts – Core Tutorial (Just Completed) Step 2: Practice – Interactive Problem Drill Step 3: Recap – Super Review Cheat Sheet Go for it! 64/64 http://www.RapidLearningCenter.com © Rapid Learning Inc. All rights reserved. :: http://www.RapidLearningCenter.com 32