What’s Going on with the Temperature? Notes for your Pre-Assessment

1. What are the states of matter? Solid (least movement of molecules) Liquid Gas (most movement of molecules; most energy)*

2. What is the change of state? A change of state is when the matter changes from one state to another by transferring enough energy (or heat) to do so.*

3. What are some examples of these changes of state? Freezing (energy is absorbed by the surroundings to change liquid into solid) Boiling (energy is absorbed by the substance to give it enough energy to transform from a liquid to a gas)*

4. What are the molecules of a substance doing when in a liquid state 4. What are the molecules of a substance doing when in a liquid state? in a gaseous state? In both liquid and gaseous states, molecules are vibrating, rotating and moving about. In the solid state, molecules are vibrating but remaining in their fixed places.*

5. How can you cause a substance to change from one state of matter to another? To go from solid to liquid to gas, add heat to increase the energy of the molecules; to go from gas to liquid to solid state, remove heat to decrease the energy of the molecules.*

6. What is meant by average atomic or molecular speed? In liquid and gaseous states, the individual atoms or molecules are moving at various rates. The average of all of the rates is the average atomic or molecular speed.*

7. What would cause the average atomic or molecular speed to increase 7. What would cause the average atomic or molecular speed to increase? Decrease? First: Increased energy; Second: Decreased energy *

8. What type of energy do we call the energy of molecules or atoms that are vibration, rotating, or moving? Kinetic energy*

9. What principle do thermometers operate on? Thermometers are devices that measure the intensity of the heat or temperature (do not confuse temperature with heat) Thermometers can measure temperature because the liquid inside of them (usually colored alcohol) expands when heated and contracts when cooled. *

10. What is absolute zero? Theoretically (has not been achieved experimentally yet), it is the temperature at which all molecular vibrations, rotations, and movement will cease. It is 0 Kelvin or -273 oC*

11. Conversions K = oC + 273 (remember it is positive because K cannot be negative) oC = K – 273 *

12. What is heat? How does it differ from temperature? Temperature measures the intensity of the heat. Temperature is measured in oC or K but heat is measured in Joules (an unit used to measure energy) *

13. Define convection The movement of matter due to differences in density that are caused by temperature variations Can result in the transfer of energy as heat*

14. Define Thermal Conduction The transfer of energy as heat through a material *

15. What is radiation? Energy that is transferred as electromagnetic waves such as visible light and infrared waves*

16. What is an insulator? A material that does not conduct energy or heat *

17. What is specific heat? The amount of energy required to raise the temperature of one gram of a substance one degree Celsius. The higher the number the more energy that is required to raise the temperature of a substance.*

18. How does specific heat explain why the water is cold on a hot summer day but the sand is so hot that it burns your feet? Both receive the same amount of heat, but water has such a high specific heat that it takes more heat to raise its temperature (so it remains several degrees colder than the sand) as compared to the sand which takes must less heat to raise its temperature (so its temperature is several degrees higher than the water). *

19. Write the specific heat equation Heat (or energy) = mass x specific heat x change in temperature E = m x SH x (Tfinal – Tinitial) SH = value depends on the material The units of SH are J / g x oC (three units) Example: water’s SH is 4.18 J/g x oC *