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Physical Behavior of Matter

Physical Behavior of Matter. Text Book: Chapters 10, 11, and 12 Review Book: Topic 4. Review: States/phases of Matter. Matter can come in the form of: Solid : matter that has a definite shape and volume. True solids have a “crystalline” structure.

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Physical Behavior of Matter

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  1. Physical Behavior of Matter Text Book: Chapters 10, 11, and 12 Review Book: Topic 4

  2. Review: States/phases of Matter • Matter can come in the form of: Solid: matter that has a definite shape and volume. True solids have a “crystalline” structure. Liquid: a form of matter that flows, has fixed volume, and takes the shape of its container. Gas: matter that has no definite shape or volume, it adopts the shape and volume of its container LOOK at the TABLE!

  3. A lot of space between particles. Particles rotate, vibrate and move around Little space between particles. Particles rotate and vibrate. No space between particles. Particles only vibrate without changing position.

  4. Things to know • Entropy refers to randomness of atoms. So, Gas would have the greatest entropy. • Enthalpy is the amount of heat retained

  5. Heating and Cooling Curves • Phase changes are physical changes - they do not involve a change in the composition of a substance. • We will now look at two types of graph curves that show s substance going from the solid to gas phase (Heating Curve) and reversely turning from gas to solid (Cooling Curve). • REMEMBER: There are two types of reactions- Endothermic (absorb heat) and Exothermic (release heat).

  6. Background: • Kinetic energy: is energy a body possesses because it is in motion…like when atoms are in motion. The average kinetic energy of the atoms or molecules is measured by the temperature of the body. • Potential energy: is the capacity for doing work that a body possesses because of its position or condition…think of it as an atom waiting to get into motion, its stored energy it can used. • Example: you are at the start line if a race…this is Potential energy. Once you begin to run…this is kinetic energy. • ** Motion (kinetic energy) produces heat…so as kinetic energy increases the phase will go from solid to liquid.

  7. Vocabulary to know: • fusion, melting: solid to liquid phase change • boiling, vaporization: liquid to gas phase change • evaporation: liquid to gas phase change of the particles on the outer surface only • solidification, freezing: liquid to solid phase change • condensation: gas to liquid phase change

  8. Heating Curve • When particles have enough kinetic energy (moving energy due to gain in heat energy) to break bonds holding them in solid phase- they melt or go through FUSION. • Amount of liquid increases and solid decreases. • Temperature continues until boiling point is reached, VAPORIZATION then begins (when attractive forces are broken among atoms that were keeping them in liquid phase).

  9. Melting Point Boiling Point

  10. Cooling Curve • The opposite of a Heating Curve

  11. Overall View

  12. Skipping a Step • Sublimation: Solid to gas phase change (the substance is said to be Sublime) Ex: Dry Ice • Deposition: gas to solid • Sublimation and Deposition are OPPOSITES!

  13. HW 1: Review book Review:

  14. Temperature and Scales • The temperature of a substance is a measure of the average kinetic energy of its particles. • “Heat” is the measure of energy transferred from one substance to another. • Scientists use Kelvin and Celsius as their scale for temperature. • Formula the know: Kelvin= Celsius + 273 • Celsius temperatures to know: 0= freezing pt of water 100= boiling pt of water -273= absolute zero

  15. Remember… • ONLY HEAT IS TRANSFERED! “Coldness” does not transfer, things become cold or cooler when their heat is transferred somewhere else. • Ex #1: if your nose is cold and you touch it with your warm hands, your hands become cooler due to the heat transfer from hands to nose. • Ex#2: Ice melting- ice is cold, and melts when it absorbs heat…making it turn into a liquid.

  16. HW #2: Review Book Question: What Kelvin Temperature is equivalent to 35°C? Work: K= C+ 273 K= 35 + 273 K= 308

  17. Measurement of Heat Energy • The amount of heat given off or absorbed in a reaction can be calculated by: q=mCΔT Where: q= heat (in joules) m= mass of the substance C= specific heat capacity of the substance ΔT= Change in temperature (Final Temp- Initial Temp) ** All the formulas you will need are on Table T of your formula sheet!

  18. Example: • Question: How many joules are absorbed when 50.0 grams of water are heated from 30.2°C to 58.6°C? • Where do we start? Always write down what you know and what you are looking for!! We Know: mass= 50.0 g Cwater= 4.18 J/g x°C (found on table B) ΔT= (58.6°C- 30.2°C)= 28.4°C We are looking for: q= joules

  19. Example…Cont • Place all the factors you know into the formula and solve. q=mCΔT q= (50.0 grams)(4.18 J/gram x °C) (28.4°C) q= 5936 J or 5.94 x 103 J Answer: 5.94 x 103J

  20. Heat of Fusion • The amount of heat needed to convert a unit mass of a substance from solid to liquid at its melting point is called HEAT OF FUSION. • The heat of fusion of solid (ice) water at 0°C and at 1 atmosphere is 334 J/g • Heat absorbed increases the potential energy of the substance without increasing the kinetic energy…so during this process there is no temperature change.

  21. Example: • Know:** Heat of Fusion, Heat of Vaporization, and Specific Heat for water can be found on Table B in your formula sheet! • Question: How many joules are required to melt 255g of ice at 0°C? • We know: m= 255 g Heat of fusion of water (from Table B)= 334 J/g • Looking for: q= ? Looking at Table T…we have to use the formula q= mHf So, we have to multiply the mass by heat of fusion value q= (255g)(334 J/g) Answer: 85,170 J = 85.2 kJ ***(1 J= 1000 kJ)

  22. Heat of Vaporization • During boiling, liquid is turned into a gaseous vapor. • Temperature is constant during this change even though energy is constantly added. • Heat energy increase the potential energy of the particles in the gaseous phase. • The amount of heat needed to convert a unit mass of a substance from its liquid phase to its vapor phase at constant temperature is called HEAT OF VAPORIZATION • The Heat of Vaporization of water at 100°C and 1 atmosphere is 2260 J/g. • ** Condensation if the reverse of the boiling process, so the heat of condensation is also 2260 J/g (exothermic).

  23. HW # 3 Review Book Example: • Question: How many joules of energy are required to vaporize 423g of water at 100°C and 1 atm? We Know: m= 423 grams Heat of Fusion (from Table T)= 2260 J/gram Looking for: q= ? Joules From Table T, we find we have to use q= mHv So, we have to multiply the mass of the substance by the heat of vaporization: q= (423 grams) (2260 J/ grams)= 955,980 J Answer: 955,980 J or 955.98 kJ

  24. HW # 4 Review Book and Text book Behavior of Gases • Kinetic molecular theory: (or KMT) is a model or theory that is used to explain the behavior of gases by describing the relationships among pressure, volume, temperature, velocity, frequency, and force of collisions. • Summary of the Theory: • Gases contain particles (usually molecules or atoms) that are in constant, random, straight-line motion. • Gas particles collide with each other and the wall of the container. These collisions could result in the transfer of energy, but there is no net loss of energy because of these collisions. Collisions are said to be perfectly elastic ( energy is completely transferred and not lost- it is the same before and after collision) • Gas particles are separated by a relatively great distance, so the volume occupied by the particles themselves is negligible and is not needed to be accounted for. • Gas particles do not attract each other.

  25. Relationship by Formula • You can figure out the relationship among pressure, temperature, and volume by using the following “Combined Gas Law” equation: P1V1 = P2V2 T1 T2 *For this equation, Temperature (T) has to be in Kelvin! **Any problem that does not give you a second number for one of the values, but states it is in “STP”- use the values on Table A for the missing values!

  26. Ideal vs Real Gases • The Kinetic molecular theory explains the behavior of gas called an “ideal gas”, but solving problems in a laboratory with “real gases” may not have the outcome predicted using the “ideal” gas. • Why does theory (what is predicted to happen) not always the real outcome? This is because two assumptions in the Kinetic molecular model are not perfectly correct.

  27. Two assumptions of the Kinetic molecular theory: • Gas particles do not attract one another: although this is usually the case because attractive forces are so small, there are extreme times that these forces are important. For example: when there is extreme cold in the atmosphere, attractive forces among the molecules make the water molecules combine to form rain or snow. • Gas particles do not occupy volume: although gas particles do not occupy large space under normal conditions, but when pressure increases this becomes important. At high pressure, the increased concentration of particles leads to more collisions and a greater chance of combining.

  28. Continued… • A gas is said to be “ideal” when it behaves as predicted, but most gases are not ideal. The closes gases to being ideal are Hydrogen and Helium. • Gases are most ideal at low pressures and high temperatures….this is why extreme cold or high pressures are important.

  29. Avogadro’s Hypothesis • Avogadro stated a theory that when the volume, temperature, and pressure of two gases were the same- they contained the same number of molecules. So, 12 liters of nitrogen at STP would contain the same number of molecules as 12 liters of oxygen at STP. Today, we believe that 22.4 liters of any gas will contain one mole of that gas. We know from our previous chapters, that 6.02 X 1023 moles are in 1 mole of any substance= Avogadro’s Number

  30. HW # 6 Essay Separation of Mixtures: Separatory Funnel • Filtration is a process of separation. Some mixtures are solids with liquids, while others are two liquids. For solids mixed with liquid, filter paper is used. Filter paper is a material with small holes (porous) that allows liquid through, but catches larger solid particles. • Mixtures composed of two liquids that are immiscible, or that don’t mix like oil and water, must be separated by a separatory funnel. After both liquids settle and separate, the valve is opened to drain the more dense liquid located at the bottom of the funnel.

  31. Separation of Mixtures: Distillation • When solids dissolve in liquids and make a homogenous solution, they must be separated by distillation. The liquid solution is brought to a boil, creating vapor that travels to a receiving flask. Once all the pure liquid travels to the receiving flask, the solid is left in the distillation flask. • If there are two liquids that are miscible, then the difference of boiling points are used to separate the two. The solution is brought to the boiling point of the solution with the lowest boiling point so that its travels through the apparatus and is caught in the receiving flask, leaving the liquid with the higher boiling point in the distillation flask.

  32. Separating Mixtures: Chromatography • There will be separation based on the properties of the chromatography paper and solution.

  33. Whew! You finished!

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