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Chapter 2

Chapter 2. Energy & Matter. Learning Target. List the different types of energy. Learning Targets. Know and apply the 3 basic forms of energy. What is Energy? . The capacity to do work or produce heat. Law of Conservation of Energy.

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Chapter 2

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  1. Chapter 2 Energy & Matter

  2. Learning Target • List the different types of energy.

  3. Learning Targets • Know and apply the 3 basic forms of energy.

  4. What is Energy? The capacity to do work or produce heat.

  5. Law of Conservation of Energy • Energy can neither be created nor destroyed in any chemical or physical process. It can be converted from one form to another.

  6. 2-1 Energy Energy is classified into three main forms Radiant Kinetic & Potential

  7. Radiant Energy This is energy from the Sun which is the result of nuclear fusion http://interestingenergyfacts.blogspot.com/2010/04/nuclear-fusion-facts.html

  8. Kinetic Energy This is the energy carried by objects in motion, like a locomotive. Kinetic Energy includes: 1. Mechanical energy carried by the moving parts of a machine 2. Thermal Energy of the random internal motion of particles in all substances (This is what is measured with temperature)

  9. Potential Energy This is the energy possessed by objects because of the position or the arrangement of their particles In essence it is stored energy.

  10. Gravitational Potential Energy The kind of energy carried by water before it falls through the spillway of a hydroelectric dam is called gravitational potential energy. Gravity is responsible for converting the potential energy of the water into kinetic energy , which is then able to do work

  11. Other forms of Potential Energy Electrical Energy is the energy that exists when objects with different electrical charges are separated. Batteries operate on this principle.

  12. Other forms of Potential Energy Chemical Energy • This is the energy which exists in some substances because of the arrangement of their particles. • Fuels and food contain chemical potential energy

  13. Learning Target – 10/8/13 Know the energy units (Calories, calories, kilojoules, joules), and how to convert from one unit to another. • What unit of energy do you personally consume everyday?

  14. Calorie (cal) [older unit] • The amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius.

  15. Example #1: How much energy is required to raise 31.0 g of water from 10°C to 25°C?

  16. Energy stored in food is often given a unit that is related to the calorie. 1 Calorie (Cal) or 1 kilocalorie =1000cal

  17. James Joule • English scientist in the mid-1800’s • Known as the father of thermodynamics • He found that changes produced by heating a substance could also be produced by mechanical energy • He discovered the relationship between mechanical energy and heat energy and formed the basis for the Law of Conservation of Energy

  18. The SI Unit of energy is the Joule (J) Joule (J) in the long form is kg.m2/s2 4.184J = 1 cal 4.184 kJ = 1kcal or 1Cal 1 kJ = 1000 J 1 Cal or kcal = 1000 cal

  19. 1cal =4.184 joules chocolate bar=200 Cal 200Cal x 4.184 kJ/Cal= Energy in one chocolate bar= 836.8kJ How many Joules? How many calories?

  20. Learning Target • Know the difference between Fahrenheit, Celsius, and Kelvin temperature scales and how to convert from one scale to another. • Explain what is meant by Absolute Zero.

  21. What is the difference between heat and temperature?

  22. Thermal Energy (Heat) vs. Temperature • Thermal Energy = sum total of all the KE of the particles in a sample. • Temperature = measure of the average KE of the particles

  23. Thermometer • The modern thermometer used in our class is filled with colored alcohol.

  24. Fahrenheit Scale • Daniel Fahrenheit developed the first alcohol thermomter in 1709 and the mercury thermometer in 1714 • He divided the freezing and boiling points of water into 180 degrees. 32° F was freezing of water and 212° F was the boiling piont. • 0° F was based on the temperature of water, ice and salt mixture.

  25. Celsius Scale • In 1742 Anders Celsius took 0° C for freezing of water and 100° C for the boiling point of water. • He dividing these points into equal scales. • Often referred to as the “centrigrade” scale which mean “divided into 100 degrees”

  26. Kelvin • Lord Kelvin used the same scale as Celsius to invent the Kelvin scale in 1848. • He developed the theoretical idea of absolute zero and this became 0 K.

  27. The Celsius Temperature Scale • The freezing point of pure water at sea level is 0º C, 32°F, 273.15 K. • The boiling point of pure water at sea level is 100ºC, 212°F, 373.15 K.

  28. Kelvin Temperature Scale • SI Unit for temperature is Kelvin (K). • The degree unit is not used in Kelvin (K),

  29. The Difference between Kelvin and Celsius • The main difference is the location of the zero point. • The zero point for kelvin is called absolute zero. • Absolute zero is equal to -273º C or 0K. • Absolute zero is the point at which the motion of particles of matter has completely stopped.

  30. Converting Kelvin and Celsius • ºC = K – 273 • K = ºC + 273

  31. Convert 50. K to the Celsius scale

  32. Converting Fahrenheit to Celsius ºC = (ºF – 32) x 5/9 Convert 67°F to °C ºC = (67º – 32) x 5/9 = 19.4 ºC

  33. Converting Celsius to Fahrenheit ºF = (9/5 x ºC) + 32 Convert -14 ºC to ºF ºF = (9/5 x -14º) + 32 = 6.8ºF

  34. Learning Target • Name and describe the 4 states of matter • Describe the differences between a physical change and chemical change.

  35. 3 States of Matter [Actually 4 States] Solid-definite shape & volume, maintains shape without a container. Liquid-definite volume but indefinite shape, takes the shape of its container but does not fill. Gas-indefinite shape & volume, fills any container placed in. Plasma-highly ionized form of gas that exists at high temps. (surface of the sun)

  36. Physical Characteristics Physical Changes-These are observed or tested without changing the substance.

  37. Physical Properties of Matter Extensive Properties- dependent on the quantity of matter. (mass, volume, shape) Intensive Properties-Not dependent on the size of the sample. (melting point, boiling point, density)

  38. Chemical Characteristics Chemical Properties-How a substance reacts with other substances. This is observed in chemical reactions. Chemical Change-When a substance is converted into a new substance. All properties and characteristics will change! Format: Reactants  Products (start) (yields) (ending)

  39. Inferences vs. Observations • Observation:  You use one or more of your five senses to know or determine something.Inference: You make an explanation for the observation.Example:  You see steam rising off of a cup of coffee.  (Observation) The coffee is hot. (Inference)

  40. Indicators of Chemical Change 1. Evolution of heat and/or light. 2. Production of a gas (not from boiling) 3. Production of a precipitate (ppt.) (solid but not from freezing) 4. Color change (be careful with this one, indicators cause color change but that is not chemical!)

  41. WARM UP A runner burns about 10 kcal per minute. If the runner completes a race in one hour and fourteen minutes, how many kJ did he burn? How many J did he burn?

  42. Learning Targets • Compare physical and chemical properties of matter. • Explain the differences between elements, compounds, and mixtures. • Explain the difference between homogeneous and heterogeneous mixtures, and techniques to separate them.

  43. Chemical Characteristics Chemical Properties-How a substance reacts with other substances. This is only observed in a chemical reaction. Chemical Change-When a substance is converted into a new substance. All properties and characteristics will change! Format: Reactants  Products (start) (yields) (ending)

  44. Physical Characteristics Physical Properties-These are observed or tested without changing the substance. Physical change -These include changes of state such as melting, boiling, dissolving, grinding, filtering, etc.

  45. Mixtures Mixture-Physical combination of 2 or more substances. 2 Classifications: Heterogeneous-different composition present [examples: sand, granite, milk of magnesia] Homogeneous-same composition present throughout [examples: salt water, Gatorade, coffee]

  46. Separation of Mixtures separate mixtures based on different physical properties of the components Different Physical Property Technique Boiling Point Distillation State of Matter (solid/liquid/gas) Filtration/Decanting Dissolves in water Evaporation

  47. Distillation

  48. Filtration

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