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?