ENERGY & MATTER Chapter 2. Learning Target List the different types of energy.
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Transcript of ENERGY & MATTER Chapter 2. Learning Target List the different types of energy.
ENERGY & MATTER
Chapter 2
Learning Target
List the different types of energy.
Learning Targets
Know and apply the 3 basic forms of energy.
What is Energy?
The capacity to do work or produce heat.
Law of Conservation of Energy
Energy can neither be created nor destroyed in any chemical or physical process. It can be converted from one form to another.
2-1 Energy
• Energy is classified into three main forms
•Radiant
•Kinetic &
•Potential
Radiant Energy
This is energy from the Sunwhich is the result of
nuclear fusionhttp://interestingenergyfacts.blogspot.com/2010/04/nuclear-fusion-facts.html
Kinetic Energy
This is the energy carried by objects in motion, like a locomotive.
Kinetic Energy includes:1. Mechanical energy carried
by the moving parts of a machine 2. Thermal Energy of the
random internal motion of particles in all substances (This is what is measured with temperature)
Potential Energy
This is the energy possessed by objects because of the position or the arrangement of their particlesIn essence it is stored energy.
Gravitational Potential Energy
• The kind of energy carried by water before it falls through the spillway of a hydroelectric dam is called gravitational potential energy.
• Gravity is responsible for converting the potential energy of the water into kinetic energy , which is then able to do work
Other forms of Potential Energy
• Electrical Energyis the energy that exists when
objects with different electrical charges are separated. Batteries operate on this principle.
Chemical EnergyThis is the energy which exists in some substances because of the arrangement of their particles. Fuels and food contain chemical potential energy
Other forms of Potential Energy
What unit of energy do you personally consume everyday?
Know the energy units (Calories, calories, kilojoules, joules), and how to convert from one unit to another.
Learning Target – 10/8/13
Calorie (cal) [older unit]
The amount of energy required to raise the temperature of 1 gram of water by 1 degree Celsius.
Example #1: How much energy is required to raise 31.0 g of water from 10°C to 25°C?
Energy stored in food is often given a unit that is related to the calorie.
1 Calorie (Cal) or 1 kilocalorie = 1000cal
James Joule
English scientist in the mid-1800’s
Known as the father of thermodynamics
He found that changes produced by heating a substance could also be produced by mechanical energy
He discovered the relationship between mechanical energy and heat energy and formed the basis for the Law of Conservation of Energy
The SI Unit of energy is the Joule (J)
Joule (J) in the long form is kg.m2/s2
4.184J = 1 cal
4.184 kJ = 1kcal or 1Cal
1 kJ = 1000 J
1 Cal or kcal = 1000 cal
1cal =4.184 joules
chocolate bar=200 Cal
200Cal x 4.184 kJ/Cal=
Energy in one chocolate bar= 836.8kJ
How many Joules? How many calories?
Learning Target
Know the difference between Fahrenheit, Celsius, and Kelvin temperature scales and how to convert from one scale to another.
Explain what is meant by Absolute Zero.
What is the difference between heat and temperature?
Thermal Energy (Heat) vs. Temperature
Thermal Energy = sum total of all the KE of the particles in a sample.
Temperature = measure of the average KE of the particles
Temperature
Peak emittance wavelength[65]
of black-body radiationKelvin Degrees Celsius
Absolute zero(precisely by definition)
0 K −273.15 °C cannot be defined
Coldest temperatureachieved[66] 100 pK −273.149999999900 °C 29,000 km
Coldest Bose–Einsteincondensate[67] 450 pK −273.14999999955 °C 6,400 km
One millikelvin(precisely by definition)
0.001 K −273.149 °C2.89777 m(radio, FM band)[68]
Water's triple point(precisely by definition)
273.16 K 0.01 °C10,608.3 nm(long wavelength I.R.)
Water's boiling point[A] 373.1339 K 99.9839 °C7,766.03 nm(mid wavelength I.R.)
Incandescent lamp[B] 2500 K ≈2,200 °C1,160 nm(near infrared)[C]
Sun's visible surface[D][69] 5,778 K 5,505 °C501.5 nm(green-blue light)
Lightning bolt'schannel[E] 28 kK 28,000 °C
100 nm(far ultraviolet light)
Sun's core[E] 16 MK 16 million °C 0.18 nm (X-rays)Thermonuclear weapon(peak temperature)[E][70] 350 MK 350 million °C
8.3×10−3 nm(gamma rays)
Sandia National Labs'Z machine[E][71] 2 GK 2 billion °C
1.4×10−3 nm(gamma rays)[F]
Core of a high-massstar on its last day[E][72]
3 GK 3 billion °C1×10−3 nm(gamma rays)
Merging binary neutronstar system[E][73] 350 GK 350 billion °C
8×10−6 nm(gamma rays)
Relativistic HeavyIon Collider[E][74]
1 TK 1 trillion °C3×10−6 nm(gamma rays)
CERN's proton vsnucleus collisions[E][75] 10 TK 10 trillion °C
3×10−7 nm(gamma rays)
Universe 5.391×10−44 s
after the Big Bang[E] 1.417×1032 K 1.417×1032 °C1.616×10−27 nm
(Planck Length)[76]
Thermometer
The modern thermometer used in our class is filled with colored alcohol.
Fahrenheit Scale
Daniel Fahrenheit developed the first alcohol thermomter in 1709 and the mercury thermometer in 1714
He divided the freezing and boiling points of water into 180 degrees. 32° F was freezing of water and 212° F was the boiling piont.
0° F was based on the temperature of water, ice and salt mixture.
Celsius Scale
In 1742 Anders Celsius took 0° C for freezing of water and 100° C for the boiling point of water.
He dividing these points into equal scales.Often referred to as the “centrigrade” scale
which mean “divided into 100 degrees”
Kelvin
Lord Kelvin used the same scale as Celsius to invent the Kelvin scale in 1848.
He developed the theoretical idea of absolute zero and this became 0 K.
The Celsius Temperature Scale
The freezing point of pure water at sea level is 0º C, 32°F, 273.15 K.
The boiling point of pure water at sea level is 100ºC, 212°F, 373.15 K.
Kelvin Temperature Scale
SI Unit for temperature is Kelvin (K).The degree unit is not used in Kelvin (K),
The Difference between Kelvin and Celsius
The main difference is the location of the zero point.
The zero point for kelvin is called absolute zero.
Absolute zero is equal to -273º C or 0K.
Absolute zero is the point at which the motion of particles of matter has completely stopped.
Converting Kelvin and Celsius
ºC = K – 273K = ºC + 273
Convert 50. K to the Celsius scale
Converting Fahrenheit to Celsius
ºC = (ºF – 32) x 5/9
Convert 67°F to °CºC = (67º – 32) x 5/9 = 19.4 ºC
Converting Celsius to Fahrenheit
ºF = (9/5 x ºC) + 32
Convert -14 ºC to ºFºF = (9/5 x -14º) + 32 = 6.8ºF
Learning Target
1) Name and describe the 4 states of matter2) Describe the differences between a physical
change and chemical change.
3 States of Matter [Actually 4 States]
Solid-definite shape & volume, maintains shape without a container.
Liquid-definite volume but indefinite shape, takes the shape of its container but does not fill.
Gas-indefinite shape & volume, fills any container placed in.
Plasma-highly ionized form of gas that exists at high temps. (surface of the sun)
Physical Characteristics
Physical Changes-These are observed or tested without changing the substance.
Physical Properties of Matter
Extensive Properties- dependent on the quantity of matter. (mass, volume, shape)
Intensive Properties-Not dependent on the size of the sample. (melting point, boiling point, density)
Chemical Characteristics
Chemical Properties-How a substance reacts with other substances. This is observed in chemical reactions.
Chemical Change-When a substance is converted into a new substance. All properties and characteristics will change!
Format: Reactants Products (start) (yields) (ending)
Inferences vs. Observations
Observation: You use one or more of your five senses to know or determine something.
Inference: You make an explanation for the observation.
Example: You see steam rising off of a cup of
coffee. (Observation)The coffee is hot. (Inference)
Indicators of Chemical Change
1. Evolution of heat and/or light.
2. Production of a gas (not from boiling)
3. Production of a precipitate (ppt.) (solid but not from freezing)
4. Color change (be careful with this one, indicators cause color change but that is not chemical!)
WARM UP
A runner burns about 10 kcal per minute. If the runner completes a race in one hour and fourteen minutes, how many kJ did he burn? How many J did he burn?
Learning Targets
1) Compare physical and chemical properties of matter.
2) Explain the differences between elements, compounds, and mixtures.
3) Explain the difference between homogeneous and heterogeneous mixtures, and techniques to separate them.
Chemical Characteristics
Chemical Properties-How a substance reacts with other substances. This is only observed in a chemical reaction.
Chemical Change-When a substance is converted into a new substance. All properties and characteristics will change!
Format: Reactants Products (start) (yields) (ending)
Physical Characteristics
Physical Properties-These are observed or tested without changing the substance.
Physical change -These include changes of state such as melting, boiling, dissolving, grinding, filtering, etc.
Mixtures
Mixture-Physical combination of 2 or more substances.
2 Classifications: Heterogeneous-different
composition present[examples: sand, granite, milk of
magnesia]
Homogeneous-same composition present throughout
[examples: salt water, Gatorade, coffee]
Separation of Mixtures
separate mixtures based on different physical properties of the components
EvaporationDissolves in water
Filtration/DecantingState of Matter (solid/liquid/gas)
Distillation Boiling Point
TechniqueDifferent Physical Property
Distillation
Filtration
Evaporation
Liquid vaporizes leaving less volatile liquid or solid.
Pure Substances
Elements & CompoundsThese always have the same properties
The same composition
They can not be separated without changing properties.
Element
A substance that can not be broken down into another substance by chemical means.
The smallest part is an atom
There are approximately 90 naturally occurring elements.
Compound
A substance that can be broken down into another substance by chemical means.
The smallest part is a molecule or ion.
Kinetic Energy (KE)
KE = ½ mv2 Unit
KE = kinetic energy J = Joule (kg.m2/s2)
m = mass kg
v = velocity m/sec
Calculate the KE of a 70kg man walking at
2.5m/s.
Potential Energy (PE)
PE=m g h m=2kgh= 40mg=9.8m/s2
PE = 2kg x 40m x 9 .8m/s2
PE = 784 Joules
What is the gravitational potential energy of a 2 kg ball at rest on a window sill, 40m up from the pavement?
WARM-UP PROBLEM
Determine the kinetic energy for a 400 g ball traveling at 3.0 km/min. (Remember to convert g to kg and km/min to m/s.)
See sample problem #4
What is the minimum height the ball would need to be dropped from to achieve this velocity before impact with the ground?