CHAPTER 2: ENERGY AND MATTER

2-1 Energy

2-2 Temperature

2-3 Matter

2-4 Elements and Compounds

2-5 Mixtures

2-1 ENERGY

Name 3 basic forms of nrg

State the law of conservation of nrg

NEED FOR NRG Heat water for cooking, bathing, etc. Provide nourishment for our bodies Travel long distances in comfort

NRG The capacity to do work or to produce

heatWork is the ability to move an object over a

distance against a resisting force A locomotive moves a train against the resisting

force of the air and friction of the wheels Sunlight striking solar panels to power a motor

against the resistance of the attached appliance A chocolate bar gives you nrg to climb a steep

hill against the resisting force of gravity

FORMS OF NRG nrg can be grouped under

3 headings Radiant nrg: light nrg

sunlight Kinetic nrg: nrg of motion

Locomotive down the tracks Mechanical nrg – moving

parts of a machine Thermal nrg – random

internal motion of particles w/in matter

Potential nrg: stored nrg because of position/ arrangement of particles Stored rain water wheel

MEASURING NRG calorie (cal): measures the amount of heat

needed to raise the temp of 1g of water 1˚C 1 cal = 1g x 1˚C

How many calories of heat would be needed to raise 5g of water 1˚C ?5g x 1˚C = 5 cal

Calorie (Cal): measures the nrg stored in food 1 Cal = 1000 cal or 1 kilocalories

Chocolate bar w/ 200 Cal = 200 kcal = 200 000 cal

Joule (J): SI unit of nrg Lifting 1 apple the length of 1 meter = 1 joule 1 cal = 4.184 J

SAMPLE PROBLEM A student uses 30. J of nrg putting books

on a shelf in the classroom. Convert this amount of nrg from joules to calories.

30. J 1 cal4.184 J = 7.2 cal

LAW OF CONSERVATION OF NRG In any process, nrg can not be created

or destroyedProcess: any situation where nrg is

converted Examples:

Hitting a baseball transfers kinetic nrg of the bat to the ball

Striking a match transforms chemical nrg into heat and light

THE NRG CRISIS If nrg is never created or destroyed, how

can we be running out of nrg?The nrg gets turned in to another form of

nrgrenewable

8%nuclear

8%

coal22%

natural gas24%

petrolium38%

2-1 SECTION REVIEW Page 60 (1-5)

2-2TEMPERATURE

Compare the Fahrenheit, Celsius, and Kelvin temperature scales

Explain what is meant by absolute zero

WHY CAN’T WE USE TOUCH TO MEASURE TEMPERATURE? There are nerves on our skin that are

sensitive to temp Some people are more sensitive than

othersA room that feels comfy to 1 person, may

feel cold to another Must use a more precise method

Thermometer – accurate and precise Galileo Galilei (1564-1642) doctor who

invented the 1st thermometer to measure the fevers in his patients.

PARTS OF A THERMOMETERFilled w/ colored alcohol

As thermometer is heated, the liquid expands and rises

As thermometer is cooled, the liquid contracts and falls

Bulb

Stem

COMPARISON OF CELSIUS AND FAHRENHEIT

Example Temperature(˚C)

Temperature(˚F)

Lowest temp in US (Prospect Creek, AK)

-62 -80

Melting ice 0 32

Room temp 21 70

“Normal” body temp 37.0 98.6

Highest temp in US (Death Valley, CA) 57 134

Boiling water 100. 212

Oven temp for baking 163 325

Surface of sun 6 000 10 000

KELVIN TEMPERATURE SCALE Unit = kelvin (K) No degree symbol (˚) is used A temperature change of 1 kelvin is the

same as a change of 1 Celsius degree Kelvin has absolute zero

The point at which all motion of particles ceases

All kinetic nrg stopsAbsolute zero = -273.15˚C

˚C = K – 273 K = ˚C + 273

EXAMPLE Temps close to absolute zero are

incredibly cold, at 50. K air will freeze into a solid! Convert 50. K to the Celsius scale.

˚C = K – 273˚C = 50. – 273˚C = -223 ˚C

PRACTICE Normal body temp is 310 K. Convert to

˚C37˚C

Antifreeze, or ethylene glycol, boils at 197˚C. Convert this to kelvin.470 K

PURSUING ABSOLUTE ZERO Read w/ your partner the Connection on

page 64Answer this questions when you are done

reading Why would it be good for scientists to reach

Absolute Zero?

2-3 MATTER

Name and describe the 4 states of matter

Compare physical and chemical properties of matter

State the law of conservation of mass

MATTER

Matter is anything that has mass and volumeAnything that

takes up space

STATES OF MATTER 4 states:

Solid Holds a particular shape, has definite volume

Molecules are rigid and structured Liquid

Does not hold shape but does have definite volumeMolecules are disordered

Gas No definite shape or volume It expands to fill the shape of the container

Molecules in constant motion Plasma

Inside stars

VIDEO

Short explanation of the matter and the 4 states of matter

PROPERTIES OF MATTER When you were at lunch today, how did

you find your friends to eat with? What did you do to find them?

PHYSICAL PROPERTIES Characteristics of a substance you can

observe w/o changing it Examples:

DensityColorMassTextureMost anything you find through using your

senses

CHEMICAL PROPERTIES Characteristics of a substance that

cannot be observed w/o changing it Examples:

Flammability – tendency to burn in air If it is a property that will change the

substance to be something else and is unreturnable, it is a chemical property

CHANGES IN MATTER Physical changes

Do not alter the identity of the substance If I tear a piece of paper into 2, 3, or even

20 pieces, it is still paper Chemical changes/Chemical reactions

Do alter the identity of the substance If I set those pieces of paper on fire, they

would no longer be paper

DIFFERENCE B/W CHEMICAL PROPERTY AND CHEMICAL CHANGE

A property is describing what could happen

A change is describing what is or what already happened

Which is the property, which the change?Leaves change colors in the FallWhen I looked out my window this morning,

I noticed the leaves are starting to change color.

SAMPLE PROBLEMS

Identify whether the underlined phrases are chemical or physical change or neither

PROBLEM #1Dear Aunt Linda,

Prom night was great fun! Tony, my date, looked very handsome in his rented tux – it was a shame the dog tore that little hole in his trousers. First we went to dinner at Chez Chemie. I was a little surprised that we had to light the candle on our own table and put ice water in the glasses, but the restaurant was vey busy and we didn’t mind. (The ice melted right away, too, and we had to add more.)

PROBLEM #2We both ordered shrimp Creole. While

we waited, we cut slices from a loaf of warm French bread – yum! My shrimp Creole was delicious. But poor Tony! The waiter was hurrying so much he spilled the whole plate on him. Tony was sweet about it, though. We got him cleaned up pretty well. He ordered a hamburger after that. He also ordered a baked potato, but he had to send it back to be cooked some more because it was still hard. It came back looking rather block, but Tony said it tasted fine.

PROBLEM #3Thank goodness it was a warm evening. We had to drive with

the windows rolled down because Tony was starting to smell like a fish market.

At the prom, we actually danced in the moonlight! (We couldn’t dance indoors on account of you know who.) We had a wonderful time. It really wasn’t anyone’s fault that Tony caught the edge of his sleeve on fire reaching over the snack table – I think too many little candles were burning on it. Mrs. Donaldson was mad that Tony dunked his arm in the punch bowl to put the fire out, but honestly what else could he do? He tipped over a vase of flowers to get to the punch bowl in time, and it shattered into a thousand pieces. Everyone stopped and stared, but no one got hurt.

On the way home, we happened to pass the tuxedo rental store, and I saw a “Help Wanted” sign. That was lucky, said Tony – he was going to need a job to pay for what happened to his suit!Love, JaniceP.S. Tony loves his new job, and just been promotes to assistant manager!

CONSERVATION OF MATTER Matter can never be created or

destroyedMeans the molecule that were here at the

beginning of time are still hereLaw of conservation of matter in effect for

the universe

ANTOINE LAVOISIER (1743 – 1794)

Uncovered the law of conservation of matter

Known for his accurate and precise measurements

The balance was his most treasured tool

Worked with his wife Killed at the guillotine

after the French Revolution b/c he was a part of a group who collected taxes for the gov’t

2-4 ELEMENTS AND COMPOUNDS

Explain the difference b/w an element and compound

ELEMENTS A substance that cannot be

separated into simpler substances by a chemical change

A little over 100 elements known today

Named after the scientist, country, state, or even planets einsteinium, americium,

californium, plutonium Use element symbols to

abbreviate names 1st letter always capital while

2nd, if there is one, will be lowercase Al for aluminum, H for hydrogen,

He for helium

Use the periodic table to organize the elements

COMPOUNDS 2+ elements combine in a chemical

reaction In fixed proportions

When magnesium is burned in air, it reacts with the oxygen in the air to produce magnesium oxide

+ air

2-5 MIXTURES

Compare heterogeneous and homogeneous mixtures

Describe several techniques to separate mixtures

MIXTURES A combination of 2 or more pure

substances in which each pure substance keeps its individual chemical propertiesThis means you can separate them after

you mix them It’s not a permanent change

Most substances want to mix, it is hard to find and keep a substance pure

EXAMPLES OF MIXTURES Sand + Water

How could we separate these?

Table salt + WaterHow could we separate these?

COMPOUND VS MIXTURE Compounds

Same composition 2 hydrogen and 1 oxygen always make water

MixturesVaried composition

Collection of elements and compounds

PURE SUBSTANCES Can be elements or

compounds How do you decide which?

Electrolysis – an electric current is passed through a sample If the sample is an element,

nothing will happen If the sample is a

compound, it will separate into the elements that make it up.

Same composition Always has the same

physical and chemical properties

Mixtures can be separated into pure substances

TYPES OF MIXTURES

HOMOGENEOUS MIXTURES Mixture that is the

same throughout Also called a

solution Examples

Sport drinksSalt waterAir you breathBrass (copper + zinc)

HETEROGENEOUS MIXTURE Mixture that has

different properties in different regions

ExamplesSand and waterCerealPizzaChocolate Chip

Cookies

HOW DO WE SEPARATE MIXTURES? Distillation Filtration Chromatography

DISTILLATION Used to separate 2 liquids Based on boiling points of each liquid

FILTRATION Used to separate a solid from a liquid

CHROMATOGRAPHY Used to separate the colors out of dyes

CHAPTER 2 REVIEW Multiple Choice

# 1-7 True or False

#8-17 Concept Mastery

#18, 19, 21(a –b), 22(a-b)

Critical Thinking and Problem Solving#26-29