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Unit I: Matter & Energy

Unit I: Matter & Energy. Textbook Chapters 1,2,11 & 12. What is Chemistry?.  Concerned with the properties of chemicals and the changes chemicals can undergo. Physical vs. Chemical Changes. H 2 O (l)  H 2 O (s).

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Unit I: Matter & Energy

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  1. Unit I: Matter & Energy Textbook Chapters 1,2,11 & 12

  2. What is Chemistry? Concerned with the properties of chemicals and the changes chemicals can undergo

  3. Physical vs. Chemical Changes H2O (l)  H2O (s) • Physical Change change in appearance but the substance itself is not changed. • Chemical Change produces new substances with different properties. • Aka Chemical Reaction H2O + ½O2 H2O2 Paper Demo Image taken from http://www.chem4kids.com/files/art/matter_intro_2_240.gif on 8/11/11.

  4. Evidence of a Chemical Change/Reaction • Evolution of a Gas • Formation of a Precipitate • Release or Absorption of Energy • Color Change in the Reaction System Image taken from http://toastyscience.edublogs.org/2011/02/02/1para-reactions-lab-1/ on 8/11/11.

  5. Properties of Matter • Physical property • Can be recognized without changing the substance to anything else. • Examples: color, odor, density, melting pt. • Chemical property • Describes how a substance reacts to form a new substance. • Examples: stable, reactive, flammable, inert Image taken from warningsignsdirect.co.uk on 8/11/11.

  6. Common States (Phases) of Matter • Solid • Liquid • Gas • Plasma Image taken from http://ds9.ssl.berkeley.edu/themis/mission_sunearth_closeup1.html on 8/11/11.

  7. Solids • Particles close together • Particles vibrate but do not move • Strong attractive forces between particles • Crystalline structure (regular geometric pattern) • Definite shape • Definite volume • Lowest PE Image taken from http://itl.chem.ufl.edu/2045_s99/lectures/FG11_001.GIF on 8/11/11.

  8. Liquids • Particles still close together. • Particles vibrate and rotate allowing for movement. • Weaker attractive forces between particles • No regular pattern of particles • Take shape of container • Definite Volume Image taken from http://itl.chem.ufl.edu/2045_s99/lectures/FG11_001.GIF on 8/11/11.

  9. Gases • Particles are very far apart and move all over. • Particles vibrate, rotate and translate (move from place to place). • Weakest attractive forces between particles. • Take shape and volume of container. • Greatest disorder • Highest PE Image taken from http://itl.chem.ufl.edu/2045_s99/lectures/FG11_001.GIF on 8/11/11.

  10. Phase Changes {Change in Position of Particles (PE)} • Types of Physical Change • Melting • Freezing (Solidification) • Vaporization (Boiling) • Condensation • Sublimation • Deposition Sublimation of Iodine Image taken from http://www.splung.com/heat/images/phases/phasediagram.png on 8/11/11.

  11. Triple point • At this temperature and pressure, substance can exist as a solid, liquid or gas. • Under higher pressure, harder for a solid to melt or a liquid to boil. • Under lower pressure, melting and boiling points lower (easier to change). Exception is water: increasing pressure, lowers freezing/melting point (think ice skating).

  12. Endothermic vs. Exothermic • Endothermic • Heat energy is absorbed. • Chemical Bonds broken in chemical rxn. • 6 kcal + H2 + I2 2HI • Exothermic • Excess heat is given off (released). • Chemical Bonds formed in chemical rxn. • CaO(s) + H2O(l)  Ca(OH)2(s) + 986 kJ/mol Images taken from uline.com and en.wikipedia.org on 8/11/11.

  13. Demo • Is this reaction exothermic or endothermic? • Ba(OH)2.8H2O + 2NH4NO3+ 170kj/molBa(NO3)2 + 2NH3 + 10 H2O

  14. Heating Curves • Endothermic or exothermic? • Be able to label all phases, phase changes, changes in temperature, PE and KE. Animated Heat Curve

  15. Cooling Curves • Endothermic or exothermic? • Be able to label all phases, phase changes, changes in temperature, PE and KE.

  16. 2 Factors Affecting Phase of a Material n.f.p.= solid-liquid equilibrium point n.b.p.= liquid-gas equilibrium point • Temperature • Pressure Image taken from http://invsee.asu.edu/srinivas/liquidmod/states.html on 8/11/11.

  17. Vapor Pressure • Evaporation • LG that takes place at the surface of the liquid and occurs at all temp’s. • From evaporation, vaporization & boiling, the gas (vapor) produced exerts a pressure called vapor pressure. • ↑Temp of liquid, ↑vapor pressure • Each substance has its own vapor pressure at differing temperatures. • Ref Table H Vp animation Image taken from http://hyperphysics.phy-astr.gsu.edu/hbase/kinetic/imgkin/vapp2.gif on 8/11/11.

  18. Boiling Point • Liquid will boil at temperature at which vapor pressure = pressure on liquid. • Point of equilibrium between gas and liquid • If vapor pressure = 1 atm (std pressure) then called the normal boiling point. • Ref Table H Image taken from http://images.tutorvista.com/content/solutions/manometer-vapour-pressure.jpeg on 8/11/11. Low pressure lowers b.p. demo

  19. 7 Diatomics • Di = 2 • Atomic = atoms • 7 elements that exist in nature as paired atoms in a molecule. • To identify them, go to PT start with element #7 and make the shape of a #7 • N2,O2,F2,Cl2,Br2,I2 • Missing one? Whose #1? • H2 Image taken from http://ths.talawanda.net/~BrambleN/classroom/Pictures/periodictablediatomic.JPG on 8/11/11.

  20. Temperature vs. Heat • Which one has more heat, a pot of boiling water or the Arctic Ocean? • Describe the temperature and heat of a 4th of July sparkler. Sparklers

  21. Temperature Δof 1oC= Δ of 1K • Measure of the average kinetic energy (KE) of the particles of a substance. • Instrument • thermometer • Units • Fahrenheit (o F) • Celsius (o C) • Kelvin (K) (SI Unit) • Ref Table T Temperature Animation Animated Temp Movie Image taken from http://www.visionlearning.com/library/module_viewer.php?mid=48 on 8/11/11.

  22. Heat • Energy transferred between objects that are at different temperatures. • Energy always flows from source to sink. • Instrument • calorimeter • Units • Calories • Joules (SI Unit) Sink ↓(Temp) Source ↑(Temp) Image taken from http://www.g9toengineering.com/resources/heattransfer.jpg on 8/11/11.

  23. Specific Heat • Amount of heat energy required to raise the temperature of 1 gram of a material 1oC • What is the specific heat capacity of water? • Ref Table B 4.18 J/goC or 4.18 J/gK • Equal to 1 calorie/goC ESCI connection metals vs. water Boiling water in a paper cup Using a bomb calorimeter to determine calories of an almond (4min) Image taken from http://media.web.britannica.com/eb-media/54/7054-004-8062DB49.gif on 8/11/11.

  24. 3 Heat Formulas (Ref Table T) • Q=mHf • Q=mHv • Q=mcΔT • Try examples! • Ref Table B Em Cee Delta Tee video Animated Heating Curve

  25. Energy Conversion • Energy • Ability to do work or transfer heat • Law of Conservation of Energy • Energy can not be created nor destroyed, just converted from one form to another. • 2 Types of Energy • Kinetic and Potential • Forms of Energy • Kinetic (motion, electrical, sound, radiant, thermal) • Potential (chemical, nuclear, gravitational, stored mechanical) Image taken from http://www.ngdir.ir/sitelinks/kids/html/energy_mfahem_science_forms%20of%20energy.html.htm on 8/11/11.

  26. Classifying Matter • Matter • Anything that has mass and volume. • Should remember terms mass, weight, volume and density (Ref Table T) from esci. [Text 1-2] Image taken from http://www.meta-synthesis.com/webbook/31_matter/matter2.jpg on 8/11/11.

  27. Elements • Substances that can not be broken down into simpler substances by chemical means. • Each element is composed of one type of atom. Examples: Review diatomics. allotropes Image taken from http://www.starkeith.net/coredump/wp-content/uploads//2008/06/the-elements.jpg on 8/11/11.

  28. Compounds • 2 or more different elements chemically combined in a definite ratio • Can be decomposed chemically into elements. Image taken from http://wiki.district87.org/images/9/91/Compounds.jpg on 8/11/11.

  29. Pure Substances • A sample of matter that has definite chemical and physical properties. • All samples of a single pure substance are identical in their properties. • Examples: • elements & • compounds Image taken from http://www.m2c3.com/chemistry/VLI/M1_Topic2/la_01_02.jpg on 8/11/11.

  30. Mixtures • 2 or more substances physically combined with no definite proportions. • In a mixture, each substance retains its own properties. • Homogeneous or Heterogeneous Image taken from http://www.m2c3.com/chemistry/VLI/M1_Topic2/la_01_02.jpg on 8/11/11.

  31. Heterogeneous Mixtures • Physical combination of substances that are NOT uniform in composition throughout. • Examples: sand & water, tossed salad, milk Milk under a microscope Image taken from http://scienceprojectideasforkids.com/wp-content/uploads/2010/06/challenge-1-sep-mix-clue.jpg on 8/11/11. Image taken from http://chestofbooks.com/reference/Facts-For-Everybody/images/Milk-474.png on 8/11/11.

  32. Homogeneous Mixtures • Physical combination of substances that are uniform in composition and properties throughout. • Examples: salt & water, all solutions and alloys Image taken from http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2010/2010%20Exam%20Reviews/Exam%201%20Review/salt_in_solution.jpg on 8/11/11.

  33. Separating Mixtures • Because mixtures are not chemically combined, they can be separated physically. • Such as…. • Filtration • Centrifugation • Chromatography • Magnetism • Distillation Image taken from http://library.thinkquest.org/11430/research/images/filtration.gif on 8/11/11. Image taken from http://images.tutorvista.com/content/chemistry-concepts/magnetic-separation-process.jpeg on 8/11/11.

  34. Distillation Fractional Distillation of Petroleum • Process by which a mixture of liquids or a liquid and a solid can be separated by different boiling points. Distillation of Saltwater Image taken from http://www.tutorvista.com/content/chemistry/chemistry-iii/organic-compounds/distillation.php on 8/11/11. Image taken from http://www.energyinst.org.uk/education/coryton/images/column.gif on 8/11/11.

  35. Image taken from http://wps.prenhall.com/wps/media/objects/165/169061/GIFS/AAAUASO0.JPG on 8/11/11.

  36. Three Ways Compounds Differ from Mixtures • Compounds are chemically combined elements. Mixtures are physically combined substances. • Compounds are formed from a definite proportion. Mixtures can have varying proportions. (Compounds have a definite formula or “recipe”. • Compounds have different properties than ingredients. Mixtures retain the same properties of the ingredients. NaCl (s) NaCl (aq) Image taken from http://www.personal.kent.edu/~cearley/ChemWrld/Reaction/H2_O2.gif on 8/11/11.

  37. Molecular Models of Matter • Can you identify the following pics as … • element, compound or mixture ??? • solid, liquid or gas??? Online practice More visuals Image taken from http://www.yenka.com/activities/Substances_and_Mixtures/attachments/Substances%20and%20Mixtures%20-%20Q2.gif on 8/11/11.

  38. Properties of Gases • Fluids • Low Density • Highly Compressible • Completely Fill a Container Propane gas can be compressed in tanks for home heating and gas barbeques. It can be so highly compressed it becomes a liquid.

  39. Pressure of Gases • Pressure • Amount of force exerted per unit area of surface. • Measured with barometer or manometer. • ex: atmospheric pressure • Units of pressure • Atmospheres • Pascals • mm of Hg • Torr Evangelista Torricelli 1606-1647 How Std. Atm. pressure is determined How a barometer works How a manometer works Demo: Can Crush Demo: pressure breaking stick Images taken from http://ths.talawanda.net/~BrambleN/classroom/Chemistry/Notes/Section%204A/PressureandTemperature.htm on 8/11/11.

  40. STP Standard Temperature and Pressure • Use Reference Table A • For Gases, • 273K = 0oC • 1atm = 29.92 inHg = 760mmHg = 760 torr = 101.3kPa • For liquids and solids, • 25oC = ?K • Same pressure Image taken from http://www.free-online-private-pilot-ground-school.com/images/standard_sealevel_pressure.gif on 8/11/11.

  41. Graham’s Law of Effusion (Diffusion) • Diffusion- spreading out from area of high to low density. • Effusion-movement of gas through a small opening into an evacuated chamber. • The rate of diffusion of a gas is inversely proportional to the square root of the gas’s density. Video Image taken from http://images.tutorvista.com/content/matter-states/diffusion-effusion-process.gif on 8/11/11.

  42. Kinetic Theory of GasesorKinetic Molecular Theory (KMT) • Gas-composed of individual particles which are in continuous, random straight line motion • Not all particles have same KE, avg KE of particles=temp of gas • Elastic collisions between particlestransfer of energy w/ no loss(Total energy stays the same.) • Volume of gas particles ignored compared to volume of space in which they contain. • Gas particlesno attraction to each other Image taken from http://www.ucolick.org/~bolte/AY4_00/week6/gas_pressure.gif on 8/11/11.

  43. Ideal Gases • Gases that follow the 5 points of KMT. • Best examples are gases with small molecular masses like H2 and He. • Low pressure and high temperature conditions are the best for ideal gases. Image taken from www.wix.com on 8/11/11.

  44. Real Gases deviate from KMT. • Especially under High pressure and Low temperatures. • Can you think of ways gases would deviate (not follow) from KMT? KMT Image taken from http://library.thinkquest.org/C006669/media/Chem/img/PV.gif on 8/11/11.

  45. Gas Laws • Boyle’s • Charles’ • Gay-Lussac • Combined • Ideal

  46. Boyles’ Law • At constant temp., volume of a given mass of gas varies inversely with pressure • PV=K or V1/V2 = P2/P1 • Example: Robert Boyle (1627-91) Image taken from http://en.wikipedia.org/wiki/Robert_Boyle on 8/11/11. Animation 2 w/ graphing Animation

  47. Charles’ Law • At constant pressure, the volume of a given mass of gas varies directly with Kelvin temperature. • V1/V2=T1/T2 or V/T=k • Example: Jacques Charles (1746-1823) Image taken from http://www.scientificamerican.com/article.cfm?id=what-is-charles-lawon 8/11/11. V Animation Balloon Demo

  48. Gay-Lussac • At constant volume, the Kelvin temperature of a gas is directly related to the pressure. • P1/T1 = P2/T2 • Example: Joseph Gay-Lussac (1778-1850) Image taken from http://www.greatscientists.net/cms/wp-content/uploads/joseph-louis-gay-lussac.jpg on 8/11/11. Pressure Cooker Animation Image taken from toolskitchen.net on 8/11/11.

  49. Combined Gas Law • Changes in volume, pressure and temperature of a gas often occur simultaneously. • Combine Boyle’s, Charles’ & Gay-Lussac’s. • Formula on Ref Table T, remember K temp. • Example: Narrated Animation of all Gas Laws

  50. Examples • A sample of 150.0 mL of oxygen gas is under 760.0 mmHg of pressure. What will be the new volume of O2(g) if the pressure is reduced to 750.0 mmHg? • A 250.0 mL Helium balloon is at a temperature of -23.0oC. What is the size of the balloon going to be if the system is warmed to 7.00oC? • A 175mL sample of gas is at 20.0oC and 1.00 atm. What will the new volume be if the temperature is lowered to 10.0oC and the pressure is raised to 1.50 atm?

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