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Chem 1H

Matter

Energy 2-1

• The capacity to do work or to produce heat

o Work is the capacity to move an object over a distance

• Forms of energy

o Kinetic energy

▪ Energy of motion

• Thrown baseball, car moving

• Mechanical energy

o Moving parts of a machine

• Thermal energy

o Random internal motion of particles in matter

o Potential energy

▪ Energy of position or arrangement of particles

• Chemical energy

o Energy stored in chemical bonds

▪ Gasoline

▪ Food

• Electrical potential energy

o Energy existing when two oppositely charged particles are separated

• Measuring Energy

o Common unit is calorie (cal)

▪ The amt of E needed to raise 1g of water 1°C

• 1 cal = 1g x 1°C

▪ How many calories does it take to raise the T of 5g of water by 1°C?

• Soln:

o Unit for food is Calorie (Cal)

▪ 1Cal = 1000cal = 1 kcal

• Typical chocolate bar has 200 Calories or 200 kcal or 200 000cal!

o There goes your 2000 calorie a day diet!

▪ SI unit is joule (J)

• Lifting an apple to a height of 1m (about 3 feet)

• James Prescott Joule

o Pioneer in understanding E

o 1 cal = 4.184 J

o Law of Conservation of Energy

▪ Energy is neither created or destroyed in a chemical reaction it is changed into another form

o Sample Problem 1 – Energy

▪ A student uses 30.J of E putting books on a shelf in the classroom. Convert this amt of E from joules to calories.

• Soln:

o Practice Problems – Energy

▪ (1) Suppose you use 135 cal of E to perform a task. How many joules have you used?

• Soln:

Ans: 565J

▪ (2) The E content of a small tomato is about 17 Cal. Convert this measurement to joules.

• Soln:

Ans: 7.1x104J

Temperature 2-2

• Fahrenheit

o Gabriel Fahrenheit

▪ fp - 32°F

▪ bp - 212°F

• Celsius

o Anders Celsius

▪ Swedish astronomer

▪ fp - 0°C

▪ bp - 100°C

• Conversion between °C and °F

o °F = 1.8(°C) + 32

o °C = (°F – 32)/1.8

o Sample Problem 2 – Temperature Conversions

▪ What is the temperature of 23°F in Celsius?

• Soln:

Ans:

• Kelvin Temperature Scale

o SI unit for T

o William Thomson, Lord Kelvin

o Absolute zero

▪ 0K or -273°C

▪ Lowest possible T

▪ All motion (their KE) in atom/molecule ceases

o A 1K change in T is the same as 1°C change in T

▪ 2K – 1K = 2°C – 1°C

• 1K = 1°C (increment between degree marks)

o Conversion between Kelvin and Celsius

▪ K = °C + 273

▪ °C = K – 273

o Sample Problem 3 – Kelvin/Celsius Conversion

▪ Temperatures close to absolute zero are incredibly cold – at 50.K air will freeze into a solid! Convert 50.K to °C.

• Soln:

Ans:

o Practice Problems

▪ (1) Normal body T is 310.K. convert 310.K to °C.

• Soln:

Ans:

▪ (2) Antifreeze, or ethylene glycol, boils at 197°C. Convert to Kelvin.

• Soln:

Ans:

Matter 2-3

• Matter

o Anything with a mass and volume

▪ Is it possible to have a mass without a volume?

▪ Is it possible to have a volume without a mass?

• States of Matter

o Solid (s)

▪ Has a definite shape and volume

▪ High density

▪ Not compressible

• Pressure does not affect density, m/V

o Liquid (l)

▪ Has a definite volume but takes on the shape of part of its container

▪ Flows freely

▪ High density

▪ Not compressible

• Pressure does not affect density, m/V

o Gas (g)

▪ No definite shape or volume

▪ Takes the shape and volume of its container

▪ Low density

▪ Very compressible

• Pressure DOES affect the density

o The more P the denser the gas

• Density depends on P

o Plasma

▪ Low density

▪ Density depends on P

▪ Exists only at high T

• Changes in state

o Heating or cooling a sample of matter

o Heating (endothermic, heat absorbed)

▪ Sublimation s to g

▪ Melting s to l

▪ Vaporization l to g

• Boiling point (bp)

o Vaporization at boiling T

• Evaporation

o Vaporization below bp

o Cooling (exothermic, heat released)

▪ Deposition g to s

▪ Freezing l to s

▪ Condensation g to l

• Properties of Matter

o Physical properties

▪ Can be observed without altering the substance

• Density, color, mp (melting point), solubility (dissolves in water), and bp

o Chemical properties

▪ Cannot be observed without altering the substance

• Flammability, reactivity with oxygen

o Does it have to react to see property?

▪ Yes ( chemical prop

▪ No ( physical prop

• Changes in matter

o Physical change

▪ Change in physical nature of substance

• Tearing, crushing, freezing, dissolving, melting, etc.

o Chemical change (or chemical reactions)

▪ Altering of substance into new substance

• Burned, reacts, combusts,

o Can I change it back by simple means?

▪ Yes ( physical change

▪ No ( chemical change

o Sample Problem 4 – Properties and Changes

▪ Determine if the underlined words describe a chemical/physical/neither change.

Dear Aunt Linda,

Prom night was great fun! Tyler, my date, looked very handsome in his rented tuxedo – it was a shame the dog tore a little hole in his pants. First we went to dinner at the Stratosphere. 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 very busy and we didn’t mind. (The ice melted right away, too, and we had to add more.)

o Practice Problems

▪ (1) Underlined physical/chemical/neither.

We both ordered shrimp scampi. While we waited, we cut slices from a loaf of warm French bread – yum! My shrimp scampi was delicious! But poor Tyler! The waiter was hurrying so much that he spilled the whole plate on him. Tyler 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 black, but Tyler said it tasted fine.

▪ (2) Identify at least one chemical change and one physical change in the following paragraph.

Thank goodness it was a warm evening. We had to drive with the windows rolled down because Tyler was starting to smell a little 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 Tyler caught the edge of his sleeve on fire, reaching over the snack table – I think too many little candles were burning on it. Mr. Dehne was mad that Tyler dunked his arm in the punch bowl to put out the fire out, but honestly what else could he do? (Fire blanket, anyone?) 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 Tyler – he was going to need a job to pay for what happened to his suit!

Love, Sandra B.

P.S. Tyler loves his new job, and he’s just been promoted to assistant manager!

• Conservation of Matter

o Matter is neither created or destroyed in a chemical reaction

o Antoine Lavoisier

▪ Recognized the role of oxygen in burning and rusting

Elements and Compounds 2-4

• Elements

o Simplest form of matter

o Cannot be separated into simpler forms of matter

o Pure substance

o Atom

▪ Simplest part of element that retains the properties of the element

o Study the elements and symbols below for a quiz.

Al aluminum Mn manganese

Ar argon Hg mercury (hydrargyrum)

As arsenic Ne neon

Ba barium Ni nickel

Be beryllium N nitrogen

B boron O oxygen

Br bromine P phosphorus

Cd cadmium Pt platinum

Ca calcium K potassium (kalium)

C carbon Ra radium

Cs cesium Rn radon

Cl chlorine Rb rubidium

Cr chromium Se selenium

Co cobalt Si silicon

Cu copper (cuprum) Ag silver (argentum)

F fluorine Na sodium (natrium)

Fr francium Sr strontium

Au gold (aurum) S sulfur

He helium Te tellurium

H hydrogen Th thorium

I iodine Sn tin

Fe iron (ferrum) W tungsten

Kr krypton U uranium

Pb lead (plumbum) Xe xenon

Li lithium Zn zinc

Mg magnesium

• Compounds

o Two or more chemically combined elements or two or more elements combine in chemical reaction

▪ 2H2(g) + O2(g) ( 2H2O(g)

▪ 6CO2(g) + 6H2O(l) ( C6H12O6 + 6O2(g) (glucose)

▪ Elements combine in fixed proportion be mass

• When magnesium burns in air, magnesium oxide is produce

o 2Mg(s) + O2(g) ( 2MgO(s)

▪ MgO is composed of 60.32% magnesium and 39.68% oxygen

o Compounds are written using the symbols of the elements and the whole number ratio between the elements

▪ Water is H2O

• Ratio: 2H:O or 2:1

• Pure substances

o Compounds and elements

▪ Unique set of physical and chemical properties

Mixtures 2-5

• Mixture is a blend of two or more types of matter

o Seawater

• Types of Mixtures

o Homogeneous mixture

▪ Called a solution

▪ Uniform composition

• Means the concentration never changes from beginning to end

o The first drink of Kool-Aid is the same as the last

• Parts are not visibly different

▪ Solvent

• Does the dissolving

o Water in Kool-Aid

▪ Solute

• Is the part dissolving

o The powder in Kool-Aid

o Heterogeneous Mixture

▪ Not uniform

▪ Parts can be visibly separated

• Chocolate chip cookies and granite

• Separating the Components of a Mixture

o Do not cause chemical change

o Filtration

▪ Heterogeneous mixture of liquid and solid

o Distillation

▪ Homogeneous mixture

• Takes advantage of the different boiling points between the two liquids in the mixture

o Petroleum refining

• When used with a dissolved solid (salt water) one can boil off the water and leave behind the salt

o Crystallization

▪ Homogeneous mixture

• When salt water is allowed to evaporate slowly crystals form

o Chromatography

▪ Homogeneous mixture

• Separate the colors in ink

o Colors move at different rates through the chromatography paper

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Matter Notes are Finished!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Please inform me of any errors.

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