unit 3

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How do we find out what everything is made out of?

Unit 3

Look around you. What do you see? In front of you

are all kinds of stuff- all sorts of matter. Some of this

matter you can see, and there’s more that you can’t.

Some substances, such as those in your body, are

undergoing transformations as we speak. And most of

it is all mixed together, which complicates things

further. What’s it all made out of? It’s a big mess. What

we need to make sense of it is a way to sort things out.

Our primary goal for this unit is to classify the matter

that is all around us. First, we’ll consider what we can

say about mixtures. As you might guess, not very

much…it varies from sample to sample. So, we will

explore some purification techniques. We will spend the

remainder of our time finding out what we can about

pure substances- these are the materials that the

universe as we know it is made from. And since nearly

all understanding of matter begins with pure substances,

purification is the first step in chemical research.

Here’s the plan:

Lesson 1: Separation Lab

Lesson 2: Leaf Lab

Lesson 3 Matter Lecture

Lesson 4: Review

Lesson 5: Matter test.

A Liquid Chromatograph-Mass Spectrometer

(LCMS) can take a complex mixture, separate it,

and identify each substance. Shown above are the

major components of a tomato (a), mustard leaf

(b), and a strawberry (c), with some individual

substances (d-f) shown below based on their mass

spectrum.

Learn more by clicking on the image.

What is a tomato, mustard leaf, and a strawberry made out of?

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Table of contents

Matter Introduction contents separation lab

Leaf lab Classifying matter Purifying matter

Properties of matter Phases of matter Liquid crystals

Separation/identification devices Classifying matter ws summary ws

Separation/identification

wsHow to Ace the Matter Unit

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sand

sand

sugar

salt

Method

pebbles

Iron filings

sugar

salt

pebbles

Iron filings Method

Methodsugar

salt

pebbles

Iron filings

sugar

salt

Iron filings

Iron filings salt

Method

Chemists typically spend more than half of their

time purifying substances- separating them into their individual pure components. As a chemist it reminded me of cleaning up a mess at home. In this lab you will be given a mixture of 5 solid ingredients. Typically, these are sand, sugar, salt, iron filings, corn kernels, and pebbles. This year, they are:

1:_____sugar__________2: ____salt__________

3: _______iron filings_______4: _____corn kernels_________

5: ____pebbles__________6: _____granular aluminum_________

Your goal is to separate all ingredients of your mixture quantitatively, and analyze your res ults. You will be graded based on your choice of methods, your report, and percent error: how close your amounts are to the actual amounts provided.

Tonight: Discuss this with your partner and come up with a plan. Write it as a diagram on the next page. You are welcome to use any equipment in the lab as long as you work safely and have it approved by me. Be ready to begin your experiment the following day. You will be allowed to dry any wet samples overnight.

Note that no student has yet come up with a quantitative method to separate salt from sugar.

Separation LabSome separation methods

to consider

filtration

Separatory funnel

decant

forceps evaporation boiling

Sample Separation Scheme

Invent your ownchromatography

Most common errors: -No separation or only partial separation of salt and sugar. -Samples still wet after overnight drying.

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Separation lab (continued)Homework: Draw a neat diagram outlining your separation procedure, using the scheme shown on the following page. Note that you will have 60 minutes of class time only over two days to complete your separations.

Sand is an ingredient, but is not actually pure, as it contains hundreds of substances in addition to quartz (SiO2)

Separation Lab: Data

Mass of mixture ________ g

Mass of component 1 (__________) ________ g

Mass of component 2 (__________) ________ g

Mass of component 3 (__________) ________ g

Mass of component 4 (__________) ________ g

Mass of component 5 (__________) ________ g

Mass of component 6 (__________) ________ g

Total mass of separated components _______ g

Percent Error ________ %

Your ScorePrecision: 1 point off for each percent error

_____ /10

Sample Purity (by inspection)

______ 10

Neatness and accuracyof report and analysis

_____ /10

Total _____ /30

Analysis: Write a paragraph summarizing your experiment, and reflect on the results. Be sure to include recommended improvements if you were to repeat the process. Use additional paper if necessary.

Once you have the stamp of approval, begin your separations. Time your work so that any sample drying takes place overnight. When you are done place each sample in a labeled plastic bag, and ieach ndividual bag in a final plastic bag- your instructor will model it for you. You will be graded based on the purity and amount of each sample. Fill in the data table and complete the Analysis section below.

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The matter all around us is rarely in a pure

form; most of what is around us are mixtures. Perhaps the most complex mixtures are those in living things. To understand what is in a mixture we must separate the individual substances contained in a mixture.

In our very first experiment you each planted a seed and by now you should have several leaves. The goal of this experiment is to isolate some pure substances from that leaf. If you have need to, bring in some fall leaves from home.

Lab 3.2 Toxicodendron radicans (Poison Ivy)

O

O

Mg

ON

N

O

O

N

N

O

O

O

H

Mg

ON

N

O

O

N

N

O

O

O

H

Every leaf contains thousands of individual chemicals. We’ll focus on three visible groups with characteristic fall colors: the carotenes, xanthophylls, and chlorophylls. Their chemical structures and typical colors are shown on the following page.

Background:

Light is a form of electromagnetic radiation. The different colors of light we see are a combination of many reflected wavelengths of light that vary from 380 - 750 nm (nanometers) in length. Each wave also has a specific amount of energy, where shorter wavelengths have more energy than longer ones. Organic compounds with more than seven alternating double bonds absorb this visible light in the visible wavelength varying from yellow to red. Compounds that are blue or green typically have not only extended alternating bonds, but also heteroatoms (atoms other than carbon and hydrogen). This includes chlorophylls A and B, which absorb that light for the plant to use. Note that we can make some rough predictions as to the color of a substance based on it’s chemical structure.

Carotenes: Gold to Orange

Xanthophylls: Light Yellow

Chlorophyll A: grass green

Chlorophyll B: Olive Green

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Each plant contains substances unique to that plant alone. Even today scientists

are isolating new substances from common plants and publishing their results. Some of these plant substances have been known to benefit us (like quinine for malaria) or hurt us(like paly toxin form Hawaiian coral).

CAUTION: The leaf extract and the chromatography solvent contain aromatic organic solvents. Itis very important that you do not breathe the fumes from the solvent. Be very careful with this solvent and wash your hands thoroughly after this exercise. The leaf extract will stain clothes. Do not spill either the leaf extract or the chromatography solvent. If there is an accidental spill, notify your instructor immediately.

Molecule Rf valueCarotenes 0.8

Xanthophylls 0.7Chlorophyll A 0.5Chlorophyll B 0.45

Leaf Chromatography: Procedure:

Grind up a few leaves using a mortar and pestle and enough acetone solvent to make a thick mush. Using a toothpick , draw a thin, straight line across the bottom of your chromatography paper as shown below. To avoid streaking don’t paint edge to edge. Put some chromatography solvent (95% hexanes, 5% acetone) in a jar so it just covers the bottom. Carefully place the paper in the jar so the solvent is below the line. Let it rise up the paper; the higher the better. Don’t let it go all the way to the top.Staple your chromatogram to this sheet and answer the following questions.

Leaf Lab (continued)

1. Identify each separated band and estimate its Rf value.

2. Repeat your experiment using 1:1 hexanes/acetone, and pure acetone. Record your observations below.

Answer the following questions at home, or in class if time allows. You should go online briefly to find your answers.2. Describe in your own words the molecular basis for chromagraphy…how does it work?Source:How chromatography works:

3. Why did acetone create the results you observed?

81. What is it? 2. Mixtures: types 3. Mixtures: purification

3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

Element, molecule, or mixture?

element element moleculemixture mixture

gold ocean milk copper glass

Think of an example of each.Element: Molecule: Mixture:

MatterUnit 3

How do we find out what everything is made out of?

Our essential question:

A good place to start:

Classify it.

Matter

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Nothing is pure in this world.What can we say about mixtures?

Looks pure but isn’t

doesn’t look pure

homogeneous heterogeneous

One thing visible

Multiple things visible

Either way it’s still a mixture…until it is separated we don’t know much about it.

1. What is it? 2. Mixtures: types 3. Mixtures: purification3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

Solutions: Gas-gas:

Gas-liquid:

liquid-liquid:solid-solid:

solid-liquid:

air

soda

Gasoline; vinegar

Salt water

brass;steel

“a solution” “a mixture”

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• want pure:

1. What is it? 2. Mixtures: types 3. Mixtures: purification3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

• Purification: How to separate mixtures.

• oil:• sand • sugar

• Technique:

• decant

• filter

• crystallize

• distill

• chromatograph

• oils • All.

• You have

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Physical vs. Chemical Properties of Matter

Stays the same New substance(s) formed

Physical Properties include:

Chemical Properties include

1. What is it? 2. Mixtures: types 3. Mixtures: purification3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

flammability rust

Melting point density magnetism malleability

ductility

color Boiling point crystallinity Refractiveindex

luster

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Extensive and Intensive Properties

Melting point

density Refractiveindex

mass

toxicity

in

inin

ex

ex

1. What is it? 2. Mixtures: types 3. Mixtures: purification3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

crystallineamorphous

• amount-dependent

• ”extent”

Doesn’t matter how much

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melt

boilcondense

deposit

cold

hot

1. What is it? 2. Mixtures: types 3. Mixtures: purification3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

liquid

solid

gas

Phase Changes

freeze

sublime

141. What is it? 2. Mixtures: types 3. Mixtures: purification3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

5 states of matter

hot

coldsolid

Liquidcrystal

liquid

gas

plasma

no

Yes-But

ordered

Yes

FillsContainer?

Yes

no

no

no

no

yes

no

no

no

no

yes

??

State?AssumesShape ofContainer? Compressible?

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Liquid crystals and plasmas

1. What is it? 2. Mixtures: types 3. Mixtures: purification3. Pure matter and it’s properties 4. States of matter 5. Liquid crystals

Coming next: the atomL2: End matter

Ordered liquids charged gases

Nematic liquid crystal:

Linear alignment

Smectic liquid crystal:

Planar alignment

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Modern Separation Methods (L1, honors only)

Still in Use

Layer separation filtrationcrystallization

Vacuum distillation Spinning band distillation

distillation

Paper chromatography

High performance liquid chromatography (HPLC)

Gas chromatographyThin layer chromatography

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Still in use

Melting point Boiling point

Nuclear magnetic resonance spectroscopy (NMR)

Mass spectrometry

All-in-one

LCMS

Flame ionization

Classical Identification Methods (L1, honors only)

Modern Identification Methods (L1, honors only

Infrared spectoscopy

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Classify each of the materials below as an element, molecule, or mixture. The examples below should help get you started. It’s OK if you miss a few…this is to get us thinking about what things are made out of. A key will be passed out after you complete this.

Element, molecule, or mixture?

A. SilverAnswer: Silver is an element (Ag).B. AirAnswer: air is a mixture of nitrogen (an element), oxygen (an element), and, among other things, carbon dioxide (a molecule).C. IceAnswer: ice the solid form of water, which is a molecule (H2O).

Classify the 19 materials on the next page, then check the answer key to see how you did.

What is everything made out of?

What is a diamond ring made out of?

matter

element molecule mixture

Classifying Matterws 3.1

What is everything made out of? Our essential question for this course:

*You should be aware that many texts differentiate between molecules and compounds. In this class we won’t go there. If you’d like to see the confusion that it can lead to, click here or here.

To say that the universe is made out of matter is true, but doesn’t provide much detail. It would help to classify mater.. Let’s start with elements.

The universe as we know it has about 100 elements. Occasionally we see them in their isolated form- for example an engagement ring may be pure gold (Au), with a diamond on it, which is pure carbon (C ).

More often we see the elements bonded together to form molecules, such as water (H2O) or table salt (NaCl). Sometimes called compounds,* molecules are made out of multiple elements which are bonded together and they have constant physical properties. For example, water freezes at 0 oC, and table salt melts at about 2000 oC.

If we look closely at the things around us, we find that most of them are mixtures of molecules. Drinking water, for example, is mostly made out molecules of water, but also has some molecules of salts (like NaCl) and may have be fluoridated as well.

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Element, molecule, or mixture?

Material Element?

Molecule? Mixture?

A. Silver

B. Air

C. ice

1. Mud2. sugar3. steam4. Baking soda5. Alumninum foil6.brass7. blood8. Bubble gum9. gatorade10. chalk11. glass12. Soy sauce13. grasshopper14. gasoline15. urine16. snow17. milk18. tobacco

19. Pencil lead (graphite)

20. Look around you. Try to find examples of elements, molecules, and mixtures in front of you right now.

1. An element in front of me:______ 2. A molecule in front of m:________3. A mixture in front of me:________

21 (L1, honors only)Use the following 6 definitions to make a classification chart similar to the one at the end of unit 1. A sample to get you started is at the bottom right of page 18.

Matter: Anything with mass and space.Element: A substance with a fixed number of protonsMolecule: Atoms bonded togetherCompound: Different atoms bonded togetherMixture: More than one substanceSubstance: A pure form of matter

each of the 7 words below on your chart as examples. Consider if some should go in more than one place.. Also ask yourself if pure elements are bonded together.

Oxygen (O2) Water Iron Carbon Diamond Graphite Sodium chloride

Matter classification chart (L1, honors only)

Humans love to classify everything.

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ws3.3

A walk on the beachIntroduction to Matter Summary Worksheet

While walking down the beach one day, I spied a small object. I noticed it has both mass and took up space, so I was sure it was ___________. I picked it up and took a look at it under a magnifying glass. I could not see any impurities in this glassy object, therefore I was pretty sure it was _____________________. I assumed it was pure, so I classified it as a ____________________.

I took it home and heated it over a fire, but it did not melt, so I can’t really say anything about that __________________(physical, chemical) property. I hammered it and it did not flatten; it is not _____________. I tried to stretch it and could not; it is not _______________. This material is a colorless solid. By the way, The other states of matter are ___________, _____________, and _____________. A few believe that _____________ represent a fifth state of matter, and this phase could either be in a ____________ or _____________ state. My little rock is just a simple solid. Since it is shiny I could say it is ___________. If I had the right equipment I could heat it up to a liquid (_________ it), or perhaps even heat it further from a liquid to a gas (_______________). It’s possible that when I heat it up it might go directly to a gas (_______________), but I doubt it. I do know that iodine vapors can cool directly to form a solid (_______________), but that has nothing to do with my story.

I happened to have some hydrofluoric acid kicking around, and when I dropped in my substance to that nasty acid, it dissolved. That _____________(physical, chemical) change was weird. I sent it out to an analysis lab and they told me that my 600 milligram sample consisted of 280 milligrams of Si (_______________), and the rest was O (_______________). The percent composition of my sample is therefore _______% Si, and ________% O. And I thought my substance was a pure element, but really it is a just a _________. I submitted several similar samples I found at the beach and they all gave exactly the same analysis; this data is very ___________. I assume the people at the lab know what they are doing so it is probably __________ as well. L1 and honors students know that if I could prepare a solution of my substance I could puriy it and have the minor impurities identified using a single machine known as a ___________.

But I’m pretty sure I know what it is already. My substance is______________.

CrystallineAmorphousMatterSubstanceCompoundSolidGasHeterogeneous

HomogeneousLiquid crystalLiquidSublimationDepositionBoilingMeltingCondensation

ChemicalPhysicalSiliconOxygenOzonePreciseaccurate

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ws3.4

I need it PureModern Purification and identification methods worksheet

After listening to the matter slideshow, especially the last two slides on modern methods of sample purification and identification, answer the questions below using some but not all of the words below

Layer separationSimple distillationFractional distillationSpinning band distillationRecrystallizationFiltrationPaper chromatographyThin layer chromatography

Gas chromatographyHigh performance liquid chromatographyMelting pointBoiling pointFlame ionization spectroscopyInfrared spectroscopyNuclear magnetic resonance

Mass spectrometryLiquid chromatograph-mass spectrometer

Place an I in front of each term above that refers to compound Identification, and a p in front of methods used for Purification

1. Which method is best for separating oil from water? __________________________2. Which method is best for separating two liquids whose boiling points only differ by one degree Celsius? ________________3. Which method is appropriate to separate 5 mg of a solid organic substance? _______________4, I’d like the elemental composition of a pure metal. A good method would be______________5. I’d like to separate a separate a sample of Martian Air into it’s individual components…a good choice would be:______________________________6. This method of sample identification is used for organic compounds, and although it provides a nice “fingerprint of the substance, has been largely replaced by more informative methods such as___________7. This method of sample identification creates predictable peaks based on the composition of the elements next to the point in question._________________________8. This method of sample identification produces a molecular ion which is a good measure of the molecular weight of the substance._______________________________________9. This is an old method of purification still in use, gives incredible sample purity, and was used in the rock candy experiment __________________________________10. This will do for separating oil and water __________________________________11. For the separation of complex mixtures which can be dissolved in a solvent, this method is hard to beat._________________________________________12. Used in the leaf lab, this method will separate a crude sample into many individual substances but is rarely used professionally. ____________________________13. This is the ultimate solution: it will separate and identify just about any solution, no matter how complex.___________________________________

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We have seen how substances may be classified based on how their atoms are arranged (for example functional groups such as aldehydes, ketones, etc.). They may also be grouped into their 5 physical states, their physical, or their chemical properties.

A chemist spends the majority of his or her time purifying mixtures, and we spent some time doing that. We used basic techniques such as decanting, filtration, distillation, and chromatography to isolate some pure substances from a mixture. L1 and honors students explored the modern equipment used for separations including high performance liquid chromatographs and spinning band distillation devices. All students learned basic methods to identify pure substances such as odor, melting point, and conversion to known compounds. L1 and honors students also learned about modern spectroscopic methods to identify substances such as nuclear magnetic resonance (NMR) spectrometers. Finally, they had a glimpse at the future with some state of the art devices that can purify a mixture and identify each substance in it such as a LC-MS (liquid chromatograph-mass spectrometer).

To ace this test be sure to understand the packet, including all lab experiments, slides, and worksheets. Go online and watch the screencasts of the slides if necessary. Be ready to separate a mixture if given one. Take a brief look at the first two units, since they are fair game on a test. Review your notes from your lab notebook, including all demonstrations and chalk talks. Finally consider the significance of the long term experiments we have been monitoring- the rock candy lab, and the seed lab. In our next unit we will zoom in enormously from our macroscopic view of matter and will ask ourselves what the smallest building blocks of matter are- this is the atom unit coming up next.

Be able to provide detailed answers to the questions below.Have a thorough understanding of the concepts below. Be able and ready to separate a mixture if given one.

Howtoaceitunit3

How to ace the Matter test

In this our third unit we learned how to purify and classify matter. Matter in its natural state is a mixture of substances, and to study them we purify and identify them, and determine their properties. The mixtures may look pure (homogeneous) or many things may be visible (heterogeneous). The pure substances occasionally are composed of only one element, but more often are molecules that consist of multiple elements bonded together. There are a nearly infinite number of individual substances on earth, and chemists have learned how to mak evirtually any new substances (though not always very quickly) of their own design.

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1. What is matter?Matter is_____________________

2. What is a substance?A substance is a __________ _________ or ____________

3. What is a physical property?

4. What is a chemical property?

5. How could I separate sand from aluminum powder?

6. What are the 5 states of matter?

7. Where can I observe plasma?

8. What are liquid crystals?

9. What are the two types of liquid crystals and how do they differ?

10. Describe the six conversions of matter states (boiling, melting…)

11. What is the law of conservation of mass?

12. Define malleable and ductile and give examples of each.

13. Heterogeneous mixture = ___________________; homogeneous mixture =___________________Homogeneous mixtures can be solid/liquid (______________), liquid/liquid (______________), gas/liquid (______________), gas/gas (______________), or even solid/solid (______________).

14. How to separate mixturesa. Sugar from sand

b. Iron from sand

c. Water from the ocean

d. Blue ink from black ink

15. What is an element?

16. What is a compound?

17. Why is chromatography such a powerful method for the separation of chemical mixtures?

18. Draw a chromatogram of a sample that has a Rf

of 0.75

19. What does HONC mean?

20. Draw propanol, C3H8O using both a structural and skeletal formula.

21. Draw two isomers of butane, C4H10,

22. To put this unit in perspective, modify the conceptual diagram at the end of unit 1 to include the main concepts of the matter unit.

22. What is an atom? This is our next unit.

Poison Ivy (Toxicodendron radicans, shown at left) produces the urushiol class of allergens, including the one shown

urushiol

Toxicodendrons radicans (poison ivy)