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Part A: Decide which of the following statements correctly describes heat. If the statement describes heat correctly, write H before the number. If.

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Presentation on theme: "Part A: Decide which of the following statements correctly describes heat. If the statement describes heat correctly, write H before the number. If."— Presentation transcript:

1 Part A: Decide which of the following statements correctly describes heat. If the statement describes heat correctly, write H before the number. If the statement does not describe heat correctly, write N.   ___N__ 1. Heat is an invisible, weightless fluid. ___N__ 2. Heat is a substance called caloric. ___N__ 3. Heat is made up of molecules. ___H__ 4. Heat moves from a warmer object to a colder object. ___N__ 5. Heat can be transferred in only one way. ___H__ 6. Heat is a form of energy. ___N__ 7. Heat is caused by the internal motions of atoms and molecules. ___H__ 8. Motion produces heat. ___N__ 9. Cold molecules move faster than warm molecules. ___N__ 10. The hotter a substance is, the less energy its molecules have.

2 Part B: These questions will help your understanding of heat and temperature.
1. What does temperature measure? Temperature measures the average kinetic energy of atoms and molecules – it’s measuring how fast they are moving.   2. Underline the correct terms: If you add kinetic energy to a sample of matter, its temperature will increase/decrease. If you take away kinetic energy from a sample of matter, its temperature will increase/decrease.   3. How are these terms related? a. temperature:thermometer – A thermometer measures temperature. b. absolute zero:temperature – Absolute zero is the absence of temperature. It is the temperature at which atoms and molecules are not moving. Its value is 0 Kelvin. c. Celcius Scale:Kelvin Scale – The Celsius and Kelvin scales are the same, they just start at different places. 0°C is the freezing pt. of water. 0 Kelvin is absolute zero. d. absolute zero:kinetic energy – Absolute zero is the absence of kinetic energy.

3 Part B - Continued e. kinetic energy:temperature – Temperature measures the kinetic energy of atoms and molecules. f. absolute zero:Kelvin Scale – Absolute zero is zero on the Kelvin scale. 4. Define heat. Explain what 2 things determine the amount of heat in a sample of matter. Heat is energy that gets transferred from one substance to another. Mass and temperature determine heat energy (also phase). 5. Decide which has more heat AND explain why. a. A pail of water at 20˚C or a cup of water at 20˚C. The pail of water. Same temperature, but higher mass. b. A pail of water at 20˚C or a pail of water at 10˚C. The 20°C pail. It has equal mass, but has a higher temperature   6. What is specific heat? The amount of heat energy required to raise one gram of a substance 1 degree Celsius.

4 Part B - Continued 7. See page 476. What is the specific heat of silver? What does this actually mean? The specific heat of silver is J/g°C. This means that it takes J of heat energy to raise the temperature of 1 gram of silver 1 degree Celsius. 8. Write the formula to calculate the amount of heat needed to change the temperature of a sample of matter. Identify what each part of the formula means. Q = m • c • ∆T Q is the change in heat energy. m is the mass of the object, c is the specific heat of the substance. ∆T is the temperature change of the substance. 9. Now, how much heat will raise the temperature of 20 g of silver from 15˚C to 20˚C? Q = m • c • ∆T = 20 g • J/g°C • 5°C = 23.5 J of energy

5 Part C: List the containers below in order of increasing heat energy
Part C: List the containers below in order of increasing heat energy. Explain why you did so. A B C D 500g 200g 200g 500g 70˚C 50˚C 25˚C 50˚C Cup C has the least temp and the least mass, so has the least heat energy. Cup B has the same temp, but a lower mass than Cup D. Cup A has both the largest mass and the highest temperature, so it goes last.

6 Part D: Complete the chart by expressing each temperature in Celcius and Kelvin. Hint: K = ˚C & ˚C = K - 273 ˚C 10 24 95 22 96 -20 -15 35 100 225 2 -273 540 -173 K 283 297 368 295 369 253 258 273 308 373 498 275 813

7 Part E: Heat transfer & thermodynamics.
1. Do the following actions involve adding heat, removing heat or no change? Putting ice into a glass of soda. Removing A can of fruit juice sits on a table all day long. No change. You hit your desk top as hard as you can. Adding You clap your hands at a basketball game. Adding A cup of hot soup sits on the table for 10 minutes. Removing Your books sit on the table for 10 minutes. No change. You carry your books outside. Either…, it depends. You put a quart of milk into the refrigerator. Removing. An ice cream cone melts in the sun. Adding.

8 Part E: Heat transfer & thermodynamics.
2. Classify each item as a conductor or an insulator. a pencil Graphite – conductor, wooden part – insulator a plastic pen insulator a metal table or tray conductor loose-leaf paper insulator your desk top insulator (plastic) a metal faucet conductor a rubber band insulator a car’s radiator. conductor

9 Part E: Heat transfer & thermodynamics.
Joules is the amount of __heat energy____ required to raise the _temperature_ of one _____gram_____ of ______water_____ by _______1______˚C. 4. How many joules of energy is removed from 10 g of water to lower its temperature 50˚C___2090 J___ 100˚C_____4180 J____ 30˚C______1254 J______?


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