making chemistry logical and relevant by jessica ames

8/8/2019 Making Chemistry Logical and Relevant by Jessica Ames

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Making Chemistry Logical and Relevant

Jessica Ames

[email protected]@lisd.net

Pre-AP/AP Chemistry Teacher, Flower Mound HS

Flower Mound, TX

Lewisville ISD

Summer, 2003

ACT2 Biennial Welch Conference

Thanks to the following sources:

Wayne Biddle's A Field Guide to the InvisibleJohn Emsley's Molecules at an ExhibitionKelly Rosier, a Chemistry teacher, who gave me the raw material for most ofmy tests and worksheets and labs!

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Random Tips

1. Use the five step method (thank you, Kelly Rosier) for solving all

problems. Students learn to think logically and can solve most

problems on their own.

I. units or variable desiredII. information given; equationIII. information needed that is not given in the problem; working equationIV. solve the problem (with units in work!)V. answer with units

Example A: What volume of gold weighs 5.0 kg if the density of gold is 19.3 g/cm 3?

I. cm3

II. 19.3 g = 1 cm3; 5.0 kgIII. 1 kg = 1000 g

IV. 5.0 kg xkg1

g1000x

g3.19

cm13

=

V. 260 cm3

Example B: How many mL of 2.0 M hydrochloric acid solution are needed to react completely with 5.0 gsodium carbonate?

I. mL HClII. 5.0 g Na2CO3III. 2 HCl + Na2CO3 --> 2 NaCl + H2O + CO2

2 mol HCl = 1 mol Na2CO31 mol Na2CO3 = 105.98 g Na2CO32.0 mol HCl = 1 L HCl

1 L = 1000 mLIV. 5.0 g Na2CO3 x 1 mol Na2CO3 x 2 mol HCl x 1 L HCl x 1000 mL =105.98 g Na2CO3 1 mol Na2CO3 2.0 mol HCl 1 L

V. 47 mL HCl

Example C: What is the mass of water if 6,500 J are required to raise the temperature by 15oC?I. m

II. Cp = q/m t q = 6,500 J t = 15oC Cp = 4.184 J/gOC

III. m = q/ Cp tIV. 6,500 J =

(4.184 J/gOC) (15oC)

V. 103 g

2. Teach significant figures from a measurement standpoint. Show the logic, before

introducing the rules. See attachment.

Make several measurements, emphasizing the number of digits that are known with certainty, andthe number of digits that can be read given a certain instrument. Then, after the students haveunderstood this, explain what a significant figure is.

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3. Emphasize concepts throughout the course. Hold students accountable

for knowledge through the duration of the course.

Example 1: Require to use the correct number of sig figs on all labs throughout the course. Youcan emphasize this by checking one measurement and/or calculation at random for sig figs on thelab. During pre-lab, emphasize the "extra decimal place" estimation on the particular instrument

that you are using.

Example 2: The AP Chemistry exam gives one digit leeway on sig figs. I do the same on tests andquizzes, in pre-AP and AP. Some teachers recommend no leeway. (However, th AP exam usuallyincludes one or two problems on the multiple choice section that require exact knowledge of sigfigs and the exact number in the answer.)

Example 3: Or, to save time, grade one question at random on each test for exact number ofsignificant figures.

Example 4: Use polyatomic ions often and in every unit after you make your students memorizethem. Then, they will see a use for them and they are more likely to truly have learned them.

Example 5: Do demonstrations that may not be relevant to a unit that you are teaching and harkback to prior knowledge. Or better yet, do a demonstration that relates the current unit of study to aprior unit of study.

Example 6: Teach a topic such as solutions piecemeal, throughout the course.

Example 7: On labs, ask questions that relate to concepts learned in prior units and let thestudents know what unit the knowledge comes from.

Example 8:On each test, put a measurement or two that must be made with the exact number ofsignificant figures.

4. For a warm-up, give a trivia question/concept. I call my daily trivia series the "AskAmes" series. I use this trivia to present interesting facts, connections of Chemistry to reallife, concepts we don't learn as much about, environmental issues, and as a TAKS review

(especially for the TEKS I don't think I cover well enough!). Of course, the students don'tknow my motivations and think it is pure random fun!

Possible topics: How diamonds are made?How the bonding graphite is different than the bonding in diamonds and why does this

give them different properties?Flatus factsProducts of petroleum distillationInteresting organic compoundsPheromonesJobs in ChemistryIsomers with totally different properties (like caraway seed and spearmint)Photosynthesis and Respiration

Global Warming FactsOzone Hole FactsThe number of atoms of different elements in your body.

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Cool facts about particular elements or compounds such as oxalic acid, bromine, goldWhat is a free radical?The density of sea waterSmoke DetectorsBody OdorGems and CompoundsNASA's $125 million mistake (the Mars Orbiter)Spontaneous Combustion

** I am currently putting my trivia series on disk. If you would like a copy, please e-mail me [email protected] (preferred) or [email protected]. Disclaimer: I have just begun this endeavor andcannot attest to the veracity of all trivia, though I try my best.

5. Sequence material so that students are using prior knowledge gained in

the course constantly.Example: (Most units are a bit large due to the fact that I teach on accelerated block scheduling)

Unit 1: Measurementand Problem Solving, Specific HeatUnit 2: Atomic Structure and Nuclear Chemistry

Unit 3: Electrons and PeriodicityUnit 4: Bonding (with a touch of organic)Unit 5: Classification of Matter, Introduction to solutions, Introduction to energy changesUnit 6: Nomenclature (also emphasize difference of properties between ionic and covalent, polar

covalent and nonpolar covalent)Unit 7: The Mole, also MolarityUnit 8: Reactions, Intro to Redox, Intro to KineticsUnit 9: Stoichiometry and Heats of Reaction (brief)Unit 10: GasesUnit 11: Acids and Bases

6. Give students something to hold when you teach the metric system or use

the metric system. (Tape a metric ruler to every desk!) Give students

various objects and have them pick up the appropriate object when you

discuss a given mass or length or volume unit.

7. Have each student hold a piece of charcoal, after or while describing how

big a mole is, to show what 1 mole of carbon is (approximately).

8. Do take-home labs! (Thank you Sara from Marcus HS)Separating a mixtureInvestigating the polarity of water and water's unique characteristicsThe temperature that doesn't occur when boiling water

Density columnCollect labels from household products and identify common compounds

9. Teach the factor label method long before you get to stoichiometry and use it all the time!

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10. Have students organize terms into categories or lists or chronologically as review.

11. Make sure there is logic and reason to everything you teach. Make sure the students can

understand what is going on and gain some insight into the chemical world.

Example: Students love the flame test lab, but make sure they "get" the fact that it is proof of the

existence of energy levels!

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NOTES: Significant Figures

What is a significant figure?

significant figures--consist of all known digits in a measurement known with certainty plus one finaldigit, which is uncertain or estimated.

For example (as shown above): A measurement made in a lab of 51.3 mL means that the measurement is anywhere between

51.25 and 51.34. We do not know whether the exact volume of the liquid was 51.36 mL or 51.43 mL because the instrument of

measurement we used did not have that much precision. To our eye, using this particular instrument, we cannot distinguishbetween 51.2 mL and 51.3 mL. Both look like 50.3 mL. The "5" and the "1" are exact and true while the ".4" is estimated.

Thus, this measured value has three significant figures.

The use of significant figures in science is important because you cannot calculate an answer that is more precise than

the measurements made were.

More Examples: How many sig figs do you think the following numbers have? (How many digits do we know withcertainty?)

Population of the earth: 6,000,000,000 6,324,654,123 6,325,000,000

Population of the school: 2500 2,505

My bank account: $1,000 $1,200 $1,200.00 $1,200.32

The money in my wallet: $10 $10.00

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Students will quickly see that 0's are the problem! You wouldn't bother to

place a "4" in a number unless you meant for the "4" to be there. But

you might use a "0" without meaning exactly "0".

So, how would I indicate that I have exactly $10 in my wallet (without meaning $11 or $9), though there

may be other change in my pocket?$1.0 x 101

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Rules to Determine the Number of Significant Figures

1. All nonzero digits are significant.421 three significant figures

2. All zeros between two significant digits (trapped zeros) are significant.4.021; 4.201; 402.1 four significant figures

3. Zeros to the right of a nonzero digit, but to the left of a decimal point (trailing zeros), are not significant. Theyare placeholders.

421,000 assume only three significant figures

4. Zeros to the right of a decimal point that are to the left of the first nonzero digit (leading zeros) are notsignificant, they are placeholders.

0.000421 three significant figures

5. All zeros to the right of a decimal point and to the right of a nonzero digit are significant.0.42100 five significant figures

6. In scientific notation, all numbers written to the left of the x 10x

portion are significant.4.21 x 102 three significant figures4.210 x 102 four significant figures4.2100 x 102 five significant figures

Remember that zeros are significant when they are used to indicate the precision of the

measurement. They are NOT significant when they are used as placeholders only.

Hint: Typically, zeroes that you would not worry about using in your math class, are written for a

reason - to show precision!

Examples:

1. 0.02

2. 0.020

3. 501

4. 501.0

5. 5,000

6. 5,000.0

7. 5.00 x 103

8. 6,051.00

9. 0.0005

10. 0.1020

11. 10,100

12. 8040

13. 0.0300

14. 699.5

15. 2.000 x 102

16. 0.90100

17. 90,100

18. 4.7 x 10-8

19. 10,800,000

20. 3.01 x 1021

DO NOT CONFUSE VALUE WITH SIGNIFICANCE!

25 and 250 both have two significant figures but have very different values.

Just because a digit is "insignificant" does not mean that it is unimportant!

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Using Significant Figures:

Multiplication and Division Involving Significant Figures

LOGIC:

Example: Imagine that you measure the mass of an object on our "crappy" digital balance that only reads one

decimal place. It says: 3.7 g

(remind students that this could mean the object is really 3.654290 g or 3.7023 g, etc., but the balance isn't preciseenough to tell us.)

Then, you measure the volume of the object (using water displacement) to be 2.2 cm3.

(remind students that object could be really 2.16 cm3 or 2.2578 cm3, but the graduated cylinder didn't have enoughlines to distinguish more precisely)

Calculate the density (as a class). Your calculator should say:1.681818182 g/cm

3

Then, you take the same object and weigh it on the really expensive digital balance and it says:

3.662 g (Why didn't we get that the first time?)Its volume is still 2.2 cm3

Its "true" density is: (according to calculator) 1.664545455 g/cm3

How many digits did the two values have in common?2.

So, it is only appropriate (when using the "crappy" balance) for us to say that the density ofthe object is

1.6 g/cm3

To give more digits would be incorrect. We don't know, with the instruments (the "crappy"balance) that we have, what the remaining digits are.

You can't have an answer that is more precise than the instruments you used to get the data!If you use crappy instruments, you get crappy data, and your answer should be equally

crappy!

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RULE:

In multiplication and division, the product or quotient should be rounded off so that there are no more

significant digits than the least precise number in your problem.

4.23 x 2.501 x 3.610 x 0.0024 =

Examples: 1. 1.35 m x 2.467 m = 4. 0.021 cm x 3.2 cm x 100.1 cm =2. 1,035 m2 x 42 m = 5. 150 L2 4 L =

3. 1.252 mm x 0.115 mm x 0.012 mm = 6. 1.278 x 103 m2 1.4267 x 102 m =

Addition and Subtraction Involving Significant Figures

LOGIC:

Example: If the population of our school is 2500 and a new student moves in today, is the population 2501?No, it was about 2500 so it is still about 2500. We didn't know what it was exactly to begin

with.

2500 really means 25??+ 1 + 12500 25?? or 2500 (placeholder 0's)

We can't add 1 to a number we don't know!

Another Example: The water in a graduated cylinder has a volume of 10.5 mL. You drop an object in it thathas a volume of 0.44 mL. What is the new total volume?

Remember that 10.5 really means 10.5???? mL

So,10.5????+ .4410.9 mL

Again, ? + 4 = ? We can't have a digit in the second decimal place since we don't know what is in the seconddecimal place in the first measurement.

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Rule:

In addition and subtraction, the arithmetic result should be rounded off so that the last significant

figure in the answer is no further right than the last significant figure in any of the data.

Tip: Add or subtract the way you did in elementary school!

23.14.77

125.38+ 3.581

More examples:

1. 12.01 mL + 35.2 mL + 6 mL = 3. 0.15 cm + 1.15 cm + 2.051 cm =

2. 55.46 g 28.9 g = 4. 505 kg 450.25 kg =

Exact conversion factors have no uncertainty and do not limit the number of significant figures in acalculation.

ex. 7 days = 1 week, 1 hour = 60 seconds, 100 cm = 1 m

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Size of the atom analogies:

If the nucleus of a uranium atom were a bowling ball sitting in front of you, the electrons would be like 92grains of sand scattered over an area the size of Dallas Fort Worth.

If the Superdome were an atom, the nucleus would be a green pea and the rest of the Superdome would beempty (except for the electrons).

If you stepped on a balance and weighed yourself, then stepped off and took off all your electrons, thenstepped back on the balance, you would weigh.....the same! (practically, so little of your weight would begone that a typical household scale would not register the difference)

The diameter of the atom is about 100,000 times larger than the diameter of the nucleus.Draw an circle on the board or overhead. Put a dot in the middle. Explain the dot is too big. Every

single atom your students have ever seen drawn before is WAY out of scale. The nucleus is always WAYTOO BIG!

The nucleus is so small that its density is 2 x 108 metric tons/cm3.

If you held a pea that had the same density as a nucleus, the pea would weigh about 250 million tons!

The number of atoms that it would take to line up across the diameter of a golf ball is equal to the number ofgolf balls it would take to line up across the diameter of the earth! (Thanks Ken Spengler)

If the nucleus of a hydrogen atom were the size of a ping pong ball, the electron would be 1/2 mile away andthe ping pong ball would weigh 5 billion tons! What would be between the ping pong ball and that electron?Empty space!

If you were a nucleus, the nearest electron would be 38 miles away. What would be between you and that

electron? Empty space!

The empty space concept (99% of an atom's volume is empty!) is very interesting to discuss because it mightlead to the conclusion that everything is mostly empty space. So, why doesn't it appear that way?

The interaction between electrons and light (and other forms of energy) give color to things andmake them appear to have a continuous surface.

The interaction/repulsion between electrons of one atom with the electrons of another atom causesthings to "feel" continuous. For example, when you touch a table, you are not actually directly

touching anything! What you feel is the large repulsive force between the electrons of your fingerand the electrons of the table.

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Cool Mole Facts!Can you truly comprehend the mole?????

A mole is sooo big that......

Hold up a mole of carbon atoms..... (12.01 g of charcoal) ...it is about a handfulThere is 1 mole of atoms in your hand, or 6.022 x 1023 atoms in your hand. (or better yet, have all of thestudents hold a piece of charcoal!)

Fact: There are about as many stars over the entire universe as there are atoms in my hand!

Q: How long would it take you to count all of the atoms in this sample, if you counted 1 each second?A: 19,089,294,774,200,000 years (that's like taking the life of this universe and living it 1 million

times!)

Q: OK, so obviously we need help! How long would it take all the members of the school to count all of theatoms in this sample? (I'm assuming 2,000 students)

A: It would still take 9,544,647,307,110 yrs (which is like living the life of this universe 600 times!)

Q: OK, so we need MAJOR HELP! Let's use everyone on earth! How long would it take to count all theatoms in my hand then?

A: about 3 million years!

Fact: Let's be more realistic!If all the people in the world were to count by ones from the time when theylearned how to count until they retired at the age of 65, they would just be able to count all of the iron atomsin the head of a straight pin.

Q: Could we try something more efficient than trying to get all the people on earth to agree to do somethingtogether for 3 million years! Let's get a computer that can count to 1 billion every second to do it! How longwould it to count all the atoms in this sample?

A: 20 million years

Fact: Indeed a mole of seconds is 4 million times the length of time the earth has existed!

Q: Obviously a mole is a huge number! And obviously atoms must be very small! If after the flood of 3000BC, Noah had started to string hydrogen atoms on a thread at the rate of one atom per second for 8 hrs a day,how long would his chain be today?

A: only 3.9 meters

Fact: There are more molecules in one teaspoon of water than there are teaspoons of water in the Atlantic

Ocean!

Fact: All the water in the Pacific Ocean is only about 1 mole of grams! (You may have to say this one morethan once!)

Q: But pennies are lots bigger than atoms! If we had a mole of pennies laid end to end, how far would theystretch?

A: A mole of atoms takes up the size of my hand, but a mole of pennies goes around the earth 270trillion times!

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Q: What if we just covered the earth in pennies as opposed to lining them end to end in a chain?A: They would cover the earth to a depth of 420 meters!

Q: That's a lot of pennies! Would a mole of pennies pay off the national debt?A: YES! And there would be enough left over to pay each US citizen 20 trillion dollars!

Fact: If one mole of pennies was divided up evenly and given to every person on earth, each person wouldreceive 1.2 x 1014 pennies. (That's a trillion bucks!) Personal spending at a rate of 1 million dollars a daywould use up each person's wealth in just under 3,000 years!

Q: Popcorn kernels are much smaller than pennies. What if we had a mole of popcorn kernels? And wecovered the earth with them?

A: We'd be covered to a depth of 9 miles! All over the earth! That is just 1 mole of popcorn kernels!

Q: What if I had a mole of Rice Crispies covering the earth?A: They would cover the earth to a depth of about 75 meters! (Or 246 feet!)

Fact: There are more rice grains in a mole of rice grains than all of the rice grains grown since the beginningof time!

Q: What if I had a mole of marshmallows covering the earth?A: They would cover the earth to a depth of 12 miles! (That's close to 5 million trillion tons of

marshmallows!)

Q: How long would it take all of us on earth to eat those marshmallows?A: If we each ate 1 marshmallow each second 24 hours a day, 7 days a week, it would take 40 million

years!

Q: How far would a stack of paper containing 1 mole of sheets of paper stretch?A: To the moon and back 80 million times!

Q: If I had a mole of dollars and gave one million dollars per second, how much would I have left when Idied?

A: If I had been alive since the day earth was created 4.5 billion years ago, I would still have 3/4thsof what I originally had!

Q: How many people would you have to have to have a mole of cells?A: Assuming that each person has 6 trillion body cells and that earth's population is 6 billion, the

whole earth's population of humans wouldn't even contain a mole of cells!

Fact: There are 46 chromosomes in each person's cell. If we had a mole of chromosomes, we'd have all thechromosomes in all of the cells of all the US population.

Q: How large would a mole of baseballs be?A: It would fit perfectly into a bag the size of the earth!

Q: So how would you feel if you dove into a mole of water molecules?A: You'd be hurt! That's only 18.02 mL of water! (Show your students this amount!)

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Some of these analogies are taken from "The Mole" song by Michael Offutt.

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LAB 10: Flame Tests and Spectroscopy

INTRODUCTION:

When elements are heated to high temperatures, some of their electrons are excited to higher energy levels.These excited electrons can then fall back to lower energy levels, releasing the excess energy in packages oflight called photons, or light quanta. The color of the emitted light depends on its energy . Blue light is

more energetic than red light, for example. When heated, each element emits a certain characteristic patternof light energies which is useful for identifying the element. The characteristic colors of light producedwhen substances are heated in the flame of a gas burner are the basis of flame tests for several elements. Inpart I of the lab, you will perform flame tests for several metallic elements.

Electrons can also be excited by electricity. So in part II of the lab, various tubes filled with gas (dischargetubes) will be excited with electricity, releasing various colors again. Then, we will look at these colorsthrough diffraction gratings, prism-like materials, and see the line emission spectra for various elements.Each element gives its own characteristic line emission spectra because of the different energy values for theenergy levels. For example, an electron falling from the 2nd energy level to the 1st energy level in one elementwill release a different photon (wavelength) than an electron falling from the 2nd energy level to the 1st energy

level in another element because their 1st

and 2nd

energy levels have different energies.

OBJECTIVES:

1. To observe the colors emitted by various metal ions.2. To evaluate flame testing as a method of detection of metals.

PART 1: Flame Tests

PROCEDURE I: (Teacher Demonstration)1. Observe as your teacher demonstrates the correct way to burn the metal ions in the Bunsen burner.2. As your teacher burns each of the metals, note the characteristic color of the flame and record it in Data

Table I.

PROCEDURE II: (Student Identification of Unknowns)1. DO NOT MOVE ANY OF THE METAL SOLUTIONS FROM ITS ASSIGNED LAB STATION. In

this lab, the student will travel around the lab.2. Starting at any lab station, note the color of the flame when the metal loop in the solution is placed in the

flame.3. Record the color noted in step 2 in THE PROPER LINE on Data Table II. Be sure to record the colors

by the correct number in the data table, not in the order you performed the test.4. Move to the next available lab station and repeat steps 1 through 3 for each of the twelve unknowns.

Remember not to move any of the metal solutions (or their wire loops) to another lab station or burner.5. Using the information in Data Table I, identify each of the unknowns.

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DATA TABLE I

ION FLAME COLOR

Sodium, Na+

Potassium, K+

Calcium, Ca+2

Barium, Ba+2

Strontium, Sr+2

Lithium, Li+

Copper, Cu+2

DATA TABLE II

UNKNOWN # FLAME COLOR METAL ION

1

2

3

4

5

6

7

8

9

10

11

12

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Part II: Spectroscopy.1. Look at various gases through a diffraction grating as your teacher puts the gas filled tubes into a lamp.

QUESTIONS:

1. Why does heating solutions of metal ions in a flame (and also adding electricity to a gas) produce acolored flame? Draw a diagram of the atom and show what causes the "color" and verbally explain it.(Yes, this is a long, detailed answer!)

2. How many photons are emitted when one electron is excited to a higher energy level and falls back to alower energy level?

3. How does the photon emitted from an electron falling from the 3rd energy level down to the 1st energylevel compare to a photon emitted from an electron falling from the 2 nd energy level down to the 1st?

4. What/Whose model of the atom did you draw in question 1?5. If electrons did not exist in specific energy levels, but were allowed to exist between energy levels, what

color light would all of the metal ion solutions (and all of the gas tubes) have emitted in this lab? Why?(You may use a diagram to answer this question.)

6. Since the above color (question 5) was not emitted, then the flame test offers proof of the existence ofwhat part of the atom?

7. What part of the atom, therefore, did Bohr discover?8. What did he look at to discover this part of the atom?9. How do scientists know what the stars are made of?10. List the colors of the visible spectrum in order of

a. decreasing energy.b. decreasing wavelengthc. increasing photon energiesd. decreasing frequency

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Ask Ames Trivia (a sample)

Facts about Flatus:

What is flatus?gas generated in or expelled from the digestive tract

How many times a day do most people pass gas?5 - 15

How much gas (in mL) is passed each occasion?35 - 90 mL (for a total of about 1L per day)

More than 99% of human flatus is composed of what odorless gases?N2, O2, CH4, CO2

Which of the above gases is explosive?

CH4 (methane; natural gas)

Even more Flatus Facts:

What microorganisms live in your gut; how many species?bacteria; more than 400

Only about 1/3 of Americans have bacteria known as methanogens that can use hydrogen to producemethane.

Methane, is produced by this reaction:4 H2 + CO2 --> CH4 + 2 H2O

So, if you have methanogens, are likely to have more less flatus than if you didn't?Less!

Methane is 25x better than CO2 at trapping heat; thus it is partially responsible for what environmentalproblem?

Global Warming

How much methane does one cow emit per day?500 L!

Gold Facts

Pure gold can be molded with the hands. Indeed, gold is so malleable that a one ounce lump of gold can beflattened into the size of a...

tennis court

Gold is so ductile that one ounce can be stretched into a wire ________ long.50 miles

24 carat gold is almost pure, except for a bit of ________ mixed in to keep it from being too soft!copper

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What fraction of 12 carat gold is gold? 18 carat? 12/24 18/24

Chemical facts about your body

You have 3.67 x 1023 atoms of this metal in your body (if you are 120 lb) that is also found in those old-timeflash cubes. What element is this?

Magnesium

Of what element do you have the most atoms?Hydrogen...If you weigh 120 lbs you have about 3.25 x 1027 (about 1,000 times more than the

number of Mg atoms you have)

Of what element do you have the most weight?Oxygen....If you weigh 120 lbs, 73.7 lbs of your weight is oxygen

Why aren't the above two answers the same?Even though you have fewer oxygen atoms than hydrogen atoms, the each oxygen atom weighs more

(16x more) than each hydrogen atom.

Cool Facts about ...an element

What element is necessary for life because it supports combustion?Oxygen

What percentage of air is composed of oxygen usually?21%

What percentage of air must be oxygen for us not to suffocate?17% or more

What is the minimum percentage of oxygen that will cause "spontaneous combustion"?25% (usually some sort of ignition is required, like the striking of a match)

Hospital patients inside oxygen tents have suffered horrific burns when they tried to light a cigarette.4 men burned to death in England repairing a ship using a drill that had inadvertantly been connected to anoxygen tank rather than compressed air...later, it was discovered that one man had tried to light a cigarette, soit wasn't so "spontaneous" after all!

What element...?

is so magnetic as liquid that it causes entire planets to become magnetized

has unpaired electrons, causing it to be magnetic

is necessary for life

is found in the body.....6.5 x 1026 atoms worth

Iron!

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Matching Exercises

How to use the following exercises:

Copy and then cut up each phrase/word. Put into an envelope.

Have students match concepts and/or order concepts/people (chronologically). To make the exercise easier or quicker, do not useeverything on the page.

Then, have students tape their words onto a piece of notebook paper to keep. OR Laminate the strips before using them, so thatthey may be used over and over again.

Quantum NumberPrincipal Quantum Number

Angular Momentum Quantum

Number

Magnetic Quantum Number

Spin Quantum Number

DescriptionTells in which energy level an electron is located

the 1st Quantum number; most general

signified by n

equals 1, 2, or 3, and so on....

Tells in which subshell/sublevel an electron is

located

signified by l

may equal 0, 1, 2, ...n - 1

tells whether an electron is in the s, p, d, or f

subshell

2nd quantum number

Tells in which particular orbital an electron is

located

Gives the orientation of an electron about the

nucleus

signified by ml

equal to any whole number from -l....+l

3rd quantum number

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distinguishes the two electrons that are

in the same orbital

4th quantum number

signified by ms

Development of the Atomic model through History

PeopleJohn Dalton

J.J. Thomson

Thomas Millikan

Ernest Rutherford

Contribution (s)developed the first modern atomic theory

said that all elements of a given element are alike

said that atoms were indivisible

Dalton model of the atom

discovered the electron

performed the cathode ray tube experiments

plum pudding model

determined the mass to charge ratio for the electron

showed that an electron weighed about 1/2000th thweight of a hydrogen atom

gold foil experiment

proved that nucleus was extremely small and dense

proved that the nucleus was positively charged

proved that most of the atom was positively charge

could not explain why the electrons did not fall intothe nucleus

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Albert Einstein

Max Planck

Niels Bohr

Louis de Broglie

Erwin Schrodinger

won the Nobel prize for explaining the photoelectrieffect

showed that electrons could be ejected from metalsby photons

showed that light had a particle nature (so light

exhibits wave-particle duality!)

also showed that light had a particle nature (so lighexhibits wave-particle duality!)

said that atoms lose specific amounts of energy,called quanta, which he measured

explained the line emission spectrum for hydrogen

discovered the existence of energy levels/shells

proved the that electrons' energies were quantized

showed that electrons exhibited wave-particle dualit

could not explain why energy levels existed

Bohr model/planetary model

compared the electrons to standing waves in that theboth had quantized (discrete) energies, wavelengths

and frequencies

explained why electrons did not fall into the nucleu

used the wave equation to predict the probablelocations of electrons in atoms

discovered the existence of subshells and orbitalswithin

energy levels/shells

used quantum numbers to describe an electron'slocation

Quantum Model

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Bohrelectrons orbited the nucleus like planets orbit the sun

explained the line emission spectrum of hydrogen

postulated that electrons' energies were quantized

discovered the "energy level"

could not explain why energy levels existed

treated electrons as particles

could not explain why electrons did not fall intonucleus

Energy levels as rings

could not explain thy the emission spectrums ofdifferent elements were different

Quantum/Schrodingerused wave equation to predict probable location of

electron

orbitals as 90% probability regions

energy levels, subshells, and orbitals

used quantum numbers to predict an electron'slocation

treated electrons as waves

lots of electron weirdness like quantum tunneling

compared electrons to standing waves

electrons do weird and bizarre things like "quantumtunneling"

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AcidspH < 7

pOH > 7

neutralize bases to produce a

salt

[H+] ( aka [H3O+]) > 1 x 10 -7

[OH-] < 1 x 10 -7

[H+] [OH-] = 1 x 10 -14

sour tasting

turns phenolphthalein clear

the higher the molarity thelower the pH

juice

BasespH > 7

pOH < 7

neutralize acids to produce a

salt

[H+] ( aka [H3O+]) < 1 x 10 -7

[OH-] > 1 x 10 -7

[H+] [OH-] = 1 x 10 -14

bitter tasting

turns phenolphthalein pink

the higher the molarity thehigher the pH

soap

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Strong Acidsat a given molarity, has a

lower pH than the other kindof acid

dissociates/ionizes completely

strong electrolyte

battery acid

HCl

Weak Acidsat a given molarity, has a

higher pH than the other kindof acid

dissociates/ionizes partially

weak electrolyte

orange juice

gastric juice

HC2H3O2

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Makes a reaction go fasterDissolving a solid reactant in

water

Heating up the reactants

Adding a catalyst

Increasing the concentration ofa reactant

Turning a liquid reactant into agaseous reactant

Using a more reactive element

Makes a reaction go slowerCooling down the reactants

Decreasing the concentrationof an aqueous reactant

Decreasing the surface area ofa reactant

Turning a liquid reactant into asolid reactant

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Compoundmade up of more than one

element

the properties of thecomponents are altered andnew properties emerge

the components bond to eachother

definite composition (only oneratio between the components

works)

can only be chemically formed

can only be chemicallyseparated

can write a chemical formula torepresent it

sodium bicarbonate

acetic acid

hydrochloric acid

salt

H2O

Mixturemade up of more than one

element

the properties of thecomponents aren't altered

the components do not bond toeach other

variable composition (morethan one way to make it)

physically formed

physically separated

pizza

salt water

Kool - Aid

person

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Ionicelectrons are transferred

forms a crystal lattice

smallest part is called aformula unit

metal + nonmetal

metal + polyatomic ion

polyatomic ion + nonmetal

polyatomic ion + polyatomicion

brittle

high melting point

electrolytic when dissolved

(can conduct electricity insolution phase)

Lewis structure is depicted likeso:

strength of bonds is measuredby lattice energy

bonding between onepolayatomic ion and another

ion

high electronegativitydifference between bonding

elements

stronger than the other type ofbond

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Covalentelectrons are shared

smallest part is called amolecule

may be polar or nonpolar

formed from all nonmetals

nonelectrolytic when dissolved

Lewis structure is depicted likeso:

may have single, double, ortriple bonds

strength of bonds is measuredby bond energy

low electronegativitydifference between bondingpartners

weaker than the other type ofbond

bonding within polyatomic ions

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Polar Covalentpartial charges on ends of

molecule

electrons shared unequally

medium electronegativitydifference between bonding

elements

nonmetal + nonmetal

two bonding elements tend to

be further away from eachother on periodic table

positively charged pole on endof molecule that is less

electronegative

negatively charged pole on endof molecule that is "hogging"

the electrons

water is an example

tends to be attracted to othermolecules of the same type

higher melting and boilingpoints (though not as high as

ionic!)

Nonpolar Covalentno partial charges on ends of

molecule

electrons shared equally

very low (or no)electronegativity differencebetween bonding elements

nonmetal + nonmetaltwo bonding elements tend tobe close together on periodic

table

carbon dioxide is an example

lower melting and boilingpoints

Please e-mail me if you would like additionalmaterials related to pre-AP or AP Chem. I'd be

happy to share whatever I have with you.

making chemistry logical and relevant by jessica ames

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