Title: Thermodynamics I. Systems A system is a group of interacting parts, including energy and matter, forming a complex whole with a common purpose.
1. Open System Definition Allows energy and matter to move in and out of the system Ex. The ocean All spheres of the Earth A Classroom
2. Closed System Definition Allows energy, but NOT matter, to move in and out of the system. * sealed ziplock bag * a sealed water bottle
3.Isolated System Definition DOES NOT allow energy or matter to move in or out of the system. The fact that, in reality, a thermos is not perfect in keeping things warm/cold illustrates the difficulty in creating a truly isolated system. In fact, there are a few, if any, systems that exist in this world that are completely isolated systems.
Isolated System Example There are not practical real world examples of this type of system.
Notes / Cornell Notes (Right Side) Thermal energy- the total energy of motion in the particles of a substance it is the energy that comes from heat. Heat- is a form of energy generated by the movement of tiny particles within an object. The faster these particles move, the more heat is generated. Stoves and matches are examples of objects that conduct thermal energy.
Foldable On the left side make a foldable for all three systems we talked about today. Word, explanation, example
Temperature Scales
Temperature-is the measure of average kinetic energy of particles in a substance.the temperature of an object tells us how HOT it is. Measured in degrees Celsius - C, F, K (Kelvin) It is NOT the same as heat energy although the two quantities are related.
What is Heat? This is the movement of thermal energy from a substance at a higher temperature to another at a lower temperature. Heat ALWAYS moves from HOT to COLD. NEVER from COLD to HOT
Equilibrium Two objects of different temperature when placed in contact will reach the same temperature + = Cold milk Light brown coffee Hot black coffee
Heat Transfer Heat always moves from a warmer place to a cooler place. Hot objects in a cooler room will warm to room temperature.
Heat Transfer Methods There are three types of heat transfer: 1.Conduction 2.Convection 3.Radiation Can we have three methods of heat transfer at one? YES! Copyright 2015 All rights reserved. www.cpalms.org
1. Conduction Happens most frequently in solids, because in solids the particles are packed closely together. Conduction Transfer of heat through matter by the direct contact of particles. Imagine it is very cold outside and you walk to school. As soon as you come inside, I hand you a mug of hot chocolate. What happens to your cold hands? Copyright 2015 All rights reserved. www.cpalms.org
2. Convection One way that liquids and gases differ from solids is that they can flow. (What does flow mean?) This makes them fluids. Convection heat transfer in a liquid or gas by flowing movement of heated particles Copyright 2015 All rights reserved. www.cpalms.org
3.Radiation Radiation is the transfer of energy by electromagnetic waves. Copyright 2015 All rights reserved. www.cpalms.org
Left Side IN Directions: Classify each example as conduction, convection, or radiation and write your answer in the chart. Conduction Convection Radiation Copyright 2015 All rights reserved. www.cpalms.org
Left Side Example 1: A pot sitting on a hot burner Example 2: Touching a metal spoon that is sitting in a pot of boiling water Example 3: A person placing their cold hands over a warm fire Copyright 2015 All rights reserved. www.cpalms.org
Left Side Example 4: Picking up a hot cup of coffee Example 5: Using an electric blanket to get warm Example 6: Putting your wet shoes on a floor vent to dry them faster. Copyright 2015 All rights reserved. www.cpalms.org
Left Side Guided Practice Example 7: Lying out in the sun to get a tan Example 8: Macaroni rising and falling in a pot of boiling water Example 9: Cold water sinking and warm water rising in the ocean Copyright 2015 All rights reserved. www.cpalms.org
Compare and Contrast: Conduction, Convection and Radiation
States of Matter States of Matter Most matter on Earth exists in three different forms: solids, liquids, and gases. Chemical composition stays the same during a change of state, but the particle makeup changes.
Solids Solids are made of particles that are packed together and they are unable to move. These particles then vibrate back and forth. Because of the vibration of the particles they have a fixed shape and volume. This is an example of what particles in a solid look like.
Liquids Particles in a liquid are close together but not as tightly packed as solids. These particles move slowly around. They do not have a definite shape, but they have adefinite volume. This is an example of what particles in a liquid look like.
Gases Particles in a gas are never packed near each other. These particles move very fast to fill all of their available space. Unlike the other forms, gases do not have a fixed volume or a definite shape. This is an example of what the particles in a gas look like.
Changes in states of matter
Specific Heat The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius. The relationship between heat and temperature change is usually expressed in the form shown below where c is the specific heat.
Q = Amount of Energy (J) m = Mass (g) c = Specific Heat (J/g C) Δt = Change in Temperature = Final T Initial T ( C)
Example Calculation Compare the amount of heat energy required to raise the temperature of 1 kg of water and 1 kg of iron 20 C? Q Q Q = mc T For Water = ( 1000g) (1cal / g For Iron o C)(20 = ( 1000g) (0.107cal / g o o C) = C)(20 o 20,000cal C) = 2140cal
1. How many joules of energy are absorbed by a pot of water with a mass of 350g in order to raise the temperature from 25 C to 30 C? (Specific heat of water = 4.18 J/g C) 7,315 J 2. If it takes 850 J of energy to warm 200g of aluminum from 30 C to 35 C, what is the specific heat (c) of aluminum? 0.85 J/g C 3. How much copper in grams would be needed if 900 J of energy were added and changed the temperature from 60 C to 95 C? (Specific heat of copper = 0.386 J/g C) 66.62 g 4. If it takes 38,200 J of heat to warm 275 g of zinc, what was the temperature change? (Specific heat of zinc = 0.387J/g C) 358.94 C