Presentation is loading. Please wait.

Presentation is loading. Please wait.

MARCH 21 st 2013. Energy Types  Electrical / Magnetic (light, magnetic fields)  Chemical (food, batteries)  Thermal (heat)  Nuclear (fission, fusion)

Similar presentations


Presentation on theme: "MARCH 21 st 2013. Energy Types  Electrical / Magnetic (light, magnetic fields)  Chemical (food, batteries)  Thermal (heat)  Nuclear (fission, fusion)"— Presentation transcript:

1 MARCH 21 st 2013

2 Energy Types  Electrical / Magnetic (light, magnetic fields)  Chemical (food, batteries)  Thermal (heat)  Nuclear (fission, fusion)  Kinetic (motion)  Potential (resting, stored up)

3 Kinetic Energy is entire objects travelling in a particular direction. Thermal Energy measures how each and every atom is wiggling or bouncing randomly all the time. KE vs. TE

4 Temperature measures the AVERAGE kinetic energy. Molecules will follow a distribution surrounding the average related to a STANDARD DEVIATION. Temperature vs. Energy Distribution

5 States of Matter TypeChange Shape?Expand to Fill Container? SolidNo LiquidYesNo GasYes Plasma*Yes *Plasma has enough Thermal Energy to separate electrons from the nucleus. **Atoms have insignificant volume and undergo elastic collisions. Match the diagram above with the description below.

6 Solids Packed tightly together. Held in place by chemical bonds. ‘Vibrate’ in place. May be crystalline in structure. May take multiple forms (allotropes)

7 Liquids Tend to stick to similar molecules (Surface tension due to intermolecular forces). ‘Wiggle’ and move around so long as touching other molecules. Have a vapor pressure which is positively correlated to temperature. Vapor pressures are the equilibrium between liquid and gas within a closed system at a certain temperature.

8 Gases Moves freely with or without contact from other atoms. ‘Bounces’ around in-between walls of container. Molecules are moving the fastest. Collisions w/ container cause pressure. Atmospheric pressure is defined as: 1 atm 760mm Hg 101.3 kPa Plasma is a special gas where e - get removed from their orbits and go free. Examples: lightning, fluorescent lights, stars Subject to forces from electric and magnetic fields. Plasma

9 Solid LiquidGasPlasma Less EnergyMore Energy ColderHotter Melting Evaporating Ionizing Boiling Vaporization Sublimating FreezingCondensing De-Ionizing Fusion Phase Changes De-sublimating

10 Phase Diagram

11 Vapor Pressures

12 Heat Transfer 1)Radiation: The hot object ‘glows’ (visibly or invisibly) and energy leaves as light, or photons. Example: campfire, toaster oven, microwave, laser 2) Conduction: High-speed atoms (hot) hit touching atoms like bumper cars, and transfer their momentum and thermal energy directly. Example: ice-cubes, stove -> skillet -> food, hot pavement -> feet 3) Convection: High-speed atoms spread out and mix with cooler atoms, increasing the overall average energy. Examples: HVAC, hot and cold water spigots, hair dryer

13 Physics of Heating Latent Heat (L) is the amount of energy required to cause a phase change. Equation: Q = m L Units: Q = heat in Joules, m = mass in grams, L = Latent heat in J/g Specific Heat Capacity (C) defines how much temperature is affected by heating within a particular phase. Equation: Q = m C ∆T Units: same, C = specific heat capacity in J/(g *K) Material Freezing Point Boiling Point Solid Specific Heat Capacity (C s ) Liquid Specific Heat Capacity (C s ) Gas Specific Heat Capacity (C s ) Latent Heat of Fusion (Lf) Latent Heat of Vaporization (Lv) Water273*K373*K2.11 J/g *K4.18 J/g *K2.08 J/g*K334 J/g2260 J/g Ammonia195 *K240 *K? (use 4.6)4.6 J/g *K2.17 J/g *K339 J/g1369 J/g Ethanol159*K352 *K2.41 J/g *K2.43 J/g *K1.70 J/g * K109 J/g838 J/g

14 Starter Gas Laws Charles’ Law V 1 / T 1 = V 2 / T 2 when P stays the same Boyle’s Law P 1 V 1 = P 2 V 2 when T stays the same Gay-Lussac’s Law P 1 / T 1 = P 2 / T 2 when V stays the same

15 Ideal Gas Law P V = n R T P = pressure V = volume n = number of moles (groups of 6.02 * 10 23 atoms or molecules) R = 8.31 L*kPa/(mol *K) called the universal gas constant T = temperature in Kelvin Measure in kPa for pressure, Liters for volume, moles for n, and Kelvin for temperature.

16 Guided Practice Problems 1)If I have a jar of air at 293 *K which has a pressure of 10 Pascals, and I place it in boiling water and let it reach thermal equilibrium, what will the new pressure be (assuming it does not expand)? 2)If I have a balloon at sea level, which I carry up a mountain until it is twice the size, what do I know about the air pressure at that elevation on the mountain? 3)A motor piston has a pressure of 100,000 Pa on both sides before the fuel ignites. Then the fuel temperature on one side goes from 293* K to 373* K. 1)What does the pressure on the hot side do? 2)What is the net pressure on the piston? 3)If the piston has an area of.1 m 2, what is the force? 4) How much volume will 4g of H 2 occupy at 400*K and 1.5 atm?


Download ppt "MARCH 21 st 2013. Energy Types  Electrical / Magnetic (light, magnetic fields)  Chemical (food, batteries)  Thermal (heat)  Nuclear (fission, fusion)"

Similar presentations


Ads by Google