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Warm-up: Gas Laws 1. If the temperature remains constant while the volume of a given amount of gas is tripled, the pressure will be 9 times the original pressure 3 times the original pressure 2/3 of the original pressure 1/3 of the original pressure 2. Boyle’s Law concerns the Pressure & volume of gases with the number of molecules and temperature constant Partial pressure of gases with temperature and volume constant Temperature and volume of gases with the number of molecules and pressure constant Temperature and pressure of gases with the number of molecules and volume constant
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Warm-up Reading a Thermometer
1. What is the reading in Celsius on the thermometer below? 2. What is the reading in Celsius on the thermometer to the right?
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Warm-up: Changes of State What is occuring on the graph?
Thermal Energy and States of Matter Warm-up: Changes of State What is occuring on the graph?
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Carbon Dioxide Triple point- the point at which the three state of matter: gas, liquid and solid coexist Critical Point- the point at which at he substance is indistinguishable between liquid and gaseous states Melting or freezing curve – curve that represents transition from liquid and solid Vaporization or condensation curve – represents th
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Phase diagram for water
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Water is more dense in the solid state so the line is moves towards the left
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3 Temperature Scales named after 3 scientists
Daniel Fahrenheit German Scientist Introduced scale in 1724 Lord William Thomson Kelvin Mathematician and Scientist who created his scale in 1848 Anders Celsius Swedish Astronomer Created his scale in 1742
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Kelvin has the same magnitude as
◦Celcius. Temperature Scales
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Temperature Conversions
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Thermal Expansion occurs in almost all substances
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Expansion Joints on a road
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Bimetallic Strips
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States of Matter Warm-up
1. Which state of matter does NOT have a definite shape or a definite volume? 2. Is condensation an endothermic or exothermic change? Refer to the phase change graph for 3, 4, & 5: 3. What is the boiling point of the substance in graph? What is the melting point? 4. How will substance change if energy is added to the liquid at 20 degrees Celcius? 5. Is water the substance in the phase change graph?
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Warm-up Why do you think heating a full pot of soup on the stove could cause the soup to overflow? Compare the ocean to a cup of hot chocolate in terms of thermal energy and temperature. Thermal Expansion The ocean has more thermal energy the cup of hot chocolate has a higher temperature
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Transfer of energy (heat) occurs by conduction,
convection, or radiation.
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Conduction
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Convection
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Convection
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Radiation
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Radiation
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Ectotherms use behaviour to control their body temperature by altering the amount of heat they are gaining or losing by convection, conduction and radiation.
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Plasma: no definite shape or volume & particles have broken apart
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Warm-ups The particles in a sample of table salt (sodium chloride) are not free to move about. They are locked in place in a structure known as a crystal lattice. Can the particles of sodium chloride possess kinetic energy? Explain why high quality thermos bottles have a vacuum lining as a major component of their insulating ability. How does an electric heater placed on the floor of a cold room warm up the air in the room?
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Melting- Endothermic change of state from SOLID to LIQUID
Melting- Endothermic change of state from SOLID to LIQUID. Example: Ice cream melting on a hot day. Vaporization- Endothermic change of state from LIQUID to GAS. Example: Puddle there one minute gone the next. Deposition- Exothermic change of state from GAS to SOLID by passing LIQUID. Example: Dry ice. Condensation- Exothermic change of state from GAS to LIQUID. Example: Rain. Freezing- Exothermic change of state from LIQUID to SOLID. Example: Water to ice. Sublimation- Endothermic change of state from SOLID to GAS by passing LIQUID. Example: Dry ice.
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Exothermic Changes Light Energy Released Light and thermal energy
Electrical Energy released from dry cell (battery)
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Warm-up: Find the Conduction, Convection, and Radiation
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- The Transfer of Heat Insulators Air between the panes of this window acts as an insulator to slow the transfer of heat.
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This picture of Lake Tahoe (on the California/Nevada border) was taken from an aircraft. But the colorful part of the lake is an infrared image that has been color-enhanced. Purple and blue show the coldest parts of the lake, while yellow and red are the warmest.
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Humans, at normal body temperature, radiate most strongly in the infrared at a wavelength of about 10 microns. A micron is the term commonly used in for a micrometer or one millionth of a meter. This image shows a man holding up a lighted match! Which parts of this image do you think have the warmest temperature? How does the temperature of this man's glasses compare to the temperature of his hand?
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The elephant has just left a pile of manure which is still much warmer than the surrounding environment. The temperature range goes from hot (white) to cold (blue). Thermography is a technique for visualizing the temperature of surfaces by recording the emission of long-wavelength infrared radiation. This heat radiation is detected electronically and displayed with different colors representing different temperatures
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In simplest terms, the Laws of Thermodynamics dictate the specifics for the movement of heat and work. First Law of Thermodynamics is a statement of the conservation of energy Second Law is a statement about the direction of that conservation Third Law is a statement about reaching Absolute Zero (0 K).
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Energy Is Neither Created Nor Destroyed
To scientists, "conservation of energy" does not mean saving energy. Instead, the law of conservation of energy says that energy is neither created nor destroyed. When we use energy, it doesn't disappear. We change it from one form of energy into another. A car engine burns gasoline, converting the chemical energy in gasoline into mechanical energy. Solar cells change radiant energy into electrical energy. Energy changes form, but the total amount of energy in the universe stays the same.
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Temperature, Thermal Energy and Heat Specific Heat A material with a high specific heat can absorb a great deal of thermal energy without a great change in temperature. Why do land and sea breezes occur?
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Heat Warm-ups mass x specific heat capacity x Δ temperature Q = mc ΔT
1. How much heat must be absorbed by 375 grams of water to raise its temperature by 25 degrees C? The specific heat of liquid water is 4.18 J/gC. 2. Which thermometer, the one inside the oven mitt or the one on the outside will have the highest temperature? 3. How much heat (in calories) is needed to raise 20 grams of water from 5 0C to 40 0C? The specific heat of water in calories is 1 cal/g0C. 375g x 4.18 J/gC x 25o C = 39,187.5 or 3.9 x 104 J Q= ? m = 20 g C= 1 cal/g0C delta t = 40 – 5 =350C Q= (20 g) (1 cal/g0C)(35 0C) Q= 700 cal
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