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EDT 181- Exam 2 review

EDT 181- Exam 2 review - EDT 181 Exam#2 Review Chapter 4...

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EDT 181- Exam #2 Review Chapter 4- Heat and Temperature I. Kinetic Molecular Theory - Idea that substances are composed of very small particles that can be traced back to certain Greek philosophers- Democritus A. Molecules All matter is made of up tiny basic units of structure called atoms Compounds - pure substances that have more complex units of structure that are not easily broken up. Ex. Water, sugar, alcohol. Molecule= tightly bonded group of atoms in which the atoms maintain their identity. Diatomic Molecules- At ordinary temperatures, the atoms of oxygen, nitrogen, and other gases are paired in groups B. Molecules Interact Cohesion- attractive force is between the same types of molecules. Without cohesion all matter would be in form of gases Adhesion- attractive force between unlike molecules C. Phases of Matter Solids - definite shapes and volumes. Fixed distances apart, bound by strong cohesive forces. Mass and space between determine density Liquid - close together and bound by cohesive forces. Can move easily from place to place. Definite volume, NOT SHAPE. Ex) A liter of water is always a liter of water. Gases - molecules with weak cohesive forces acting between them. Far apart, move freely in constant motion. NO FIXED SHAPE OR VOLUME Plasmas - gases made up of positive ions and negative electrons. Conduct electricity, magnetic. Ex. Neon, fluorescent lights, sun, stars Vapor - Describe a gas that is in liquid phase. Ex. Water vapor D. Molecules Move Ammonia molecules diffuse or spread throughout the room. Diffuse faster in high temperature and slower in lower. Temperature of gas is proportional to average kinetic energy. II. Temperature- Measure of the average kinetic energy of the molecules making up the substance. How hot or cold something is… A. Thermometers Measures the hotness or coldness of something. Materials expand with increasing temperatures Measures hottest temperature.
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B. Temperature Scales Fahrenheit Scale- Degrees of temperature scale. (Freezing boiling= 180 degrees. Tf= 9/5 (Tc) + 32 Celsius Scale- Freezing and boiling of water at normal atmospheric pressure. Tc= 5/9 (Tf-32) Kelvin Scale- Lowest possible temperature is absolute zero, (0K). Freezing= 273 and Boiling= 373. Tk= Tc + 273 III. Heat - Used to describe the “something” that moves between objects when two objects of different temperatures are brought together. External Energy- Total potential and kinetic energy of everyday sized objects. Internal Energy- Total kinetic and potential energy of the molecules of an object. Ex) temp, heat, density, volume, pressure of gas ect… A. Heat as Energy Transfer Heat is a measure of the total internal energy of the molecules of the body. If object has same temperature, they have same average kinetic energy. More total energy takes longer to cool down Heating- process of increasing internal energy Cooling- process of decreasing internal energy Heating plus Cooling= direction of energy flow B. Two Heating Methods 1)
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EDT 181- Exam 2 review - EDT 181 Exam#2 Review Chapter 4...

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