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Honors Biology Chapter 2 Chemistry

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Honors Biology Chapter 2. Chemistry. DRY ERASE ATOM ATTITUDE. Everyone gets a dry erase board, dry erase pen, and tissue for erasing. The teacher will ask you a question about atomic structure, you will write your answer and hold up your board. - PowerPoint PPT Presentation

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Page 1: Honors Biology Chapter 2

Honors Biology Chapter 2

Chemistry

Page 2: Honors Biology Chapter 2

DRY ERASE ATOM ATTITUDE

• Everyone gets a dry erase board, dry erase pen, and tissue for erasing.

• The teacher will ask you a question about atomic structure, you will write your answer and hold up your board.

Page 3: Honors Biology Chapter 2

Are you wondering why we are learning chemistry in biology class?• All of our cells are made of chemical

compounds.

• All the activities of our bodies work on chemical reactions.

• All of our body’s reactions use water.

Such as neurotransmitters affecting neurons

Page 4: Honors Biology Chapter 2

MATTER

• Anything that occupies space (VOLUME) and has MASS

• Is air matter?• Yes

Page 5: Honors Biology Chapter 2

Match as energy (capacity to do work) or matter (occupies space

and has mass)

• Water• Electricity• Air• Helium• Sunlight• Iron• Carbon

• Matter• Energy• Matter• Matter• Energy• Matter• Matter

Page 6: Honors Biology Chapter 2

2.1 ELEMENTS, ATOMS, 2.1 ELEMENTS, ATOMS, COMPOUNDS (are matter)COMPOUNDS (are matter)

Page 7: Honors Biology Chapter 2
Page 8: Honors Biology Chapter 2

YOU NEED TO KNOW

• The Names (spelled correctly) and the Symbols (written correctly) on p. 18 (Table 2.1)

• “Elements in the Human Body”• 25 elements (includes trace

elements)• QUIZ on FRIDAY Sept. 27

Page 9: Honors Biology Chapter 2

ELEMENTS

• Substance that cannot be broken down to other substances by ordinary chemical means (heating, adding an acid…)

• YouTube - ?Tom Lehrer's

The Elements" animated??

***ASAP SCIENCE Periodic Table

In Order

OR YouTube - ?The Elements Animation??

Page 10: Honors Biology Chapter 2

Where can you find an element?

The Periodic Table of the Elements – see Appendix 2 and get your personal copy

Page 11: Honors Biology Chapter 2

ELEMENTS AND SYMBOLS:Ca, H, Li, O, C, Mg

• What rules apply to writing the symbols (abbreviations of the elements)?

• First letter capital, second letter is lower case

• What are the four most common elements in the human body? (see chart)

• CHON• What are trace elements?• Less than 0.01% of human body weight

Page 12: Honors Biology Chapter 2

Which are elements?

• Cu• C• CO• N• NO• WHY?• Cu C N only

one kind of matter Gold - Au

Page 13: Honors Biology Chapter 2

COMPOUNDS• Substance of two or more different atoms chemically

combined in a fixed ratio• EXAMPLES: CO2

• H2SO4

• H2O

• CO• How is a compound written differently than an element?• More than one kind of element (more than one capital

letter).• NOTE: H2 is not a compound – its an element• (Only one kind of element)

Subscripts (tell how many atoms there are)

Page 14: Honors Biology Chapter 2

Formula

• Formula is the abbreviation for a compound.

• CO2 H2SO4 H2O• Carbon dioxide sulfuric acid water• What rules seem to apply to writing a

formula?• Capital letters for elements• Subscript number behind and just below

the line of what element it represents

Page 15: Honors Biology Chapter 2

Which are compounds?

• Na N H2 NO2 H2O Why?

• NO2

• H2O• 2 or more different elements

chemically joined (2+ diff. capital letters)

Page 16: Honors Biology Chapter 2

Which are symbols?Abbreviations for elements

• C CO2 Mn CO Ni Why?

•C Mn Ni • Only one capital letter

Page 17: Honors Biology Chapter 2

What’s the difference?

• Co CO co

• Symbol formula nothing

Page 18: Honors Biology Chapter 2

Which are formulas?Abbreviation for a compound

• H2SO4 Cl2 H20 Al Why?

H2SO4 H20 abbreviations for compounds (2 or more different kinds of elements)

Page 19: Honors Biology Chapter 2

Can you figure out the difference between a mixture and a

compound?

• A mixture is two or more elements (or compounds) NOT chemically joined.

• A compound is two or more atoms chemically joined.• Do Worksheet: Elements, Compounds, Mixtures

Page 20: Honors Biology Chapter 2

DO WORKSHEET: Elements, Compounds, Mixtures

• (back of Atomic Mass and Atomic Number Worksheet)

• Work in groups of three, then we’ll compare answers.

Page 21: Honors Biology Chapter 2

2.2 What are trace elements?• Needed in the body in only small

amounts• Like mg (milligrams)• WHY IMPORTANT IF WE DON’T

NEED SO MUCH?• Minerals act as catalysts (speed up

reactions) for many biological reactions

Page 22: Honors Biology Chapter 2

Trace Elements

Needed by some organisms but only in very small amountsLike iodine, we need only 0.15 mg per dayA deficiency will cause a goiter

Page 23: Honors Biology Chapter 2

Trace Elements

• Fluorine – in drinking water, toothpaste

• (help dental decay) But too much can cause fluorosis (white chalky build-up)

Page 24: Honors Biology Chapter 2

Trace Elements

• Iron Rich Foods

• Most important

use is to carry

oxygen in the blood

Page 25: Honors Biology Chapter 2

2.3 Atoms and Molecules

Page 26: Honors Biology Chapter 2

Atoms are made of protons, neutrons, electrons

• Do you know what these particles are?

Page 27: Honors Biology Chapter 2

Answers:

• Do you know what these particles are?

Protons

Neutrons

Electrons

Page 28: Honors Biology Chapter 2

• Basic Atomic Structure Youtube (1:57)

Page 29: Honors Biology Chapter 2

Atom

• Smallest unit of matter that retains the properties of the element

Li

Na

Page 30: Honors Biology Chapter 2

Which shows one atom?

• C N N2 H20 Why?

• C and N • only one in number • Which are elements?• C N N2

Page 31: Honors Biology Chapter 2

Molecule

• Two or more atoms held together by chemical bonds

Page 32: Honors Biology Chapter 2

Which are molecules?

• Co CO CO2 O2

Why?

• CO CO2 O2 two or more atoms (alike or not alike, it doesn’t matter) bonded together

Page 33: Honors Biology Chapter 2

Where is each subatomic particle located?

• Proton in the

• Neutron nucleus

Electron-outside the nucleus

• Golden Retrievers Show Atomic Structure Youtube (2:11)

Page 34: Honors Biology Chapter 2

What is the charge of each subatomic particle?

• Proton Neutron Electron

• + O _• positive none negative

Page 35: Honors Biology Chapter 2

What is the relative size?

• Proton neutron electron

• 1 amu 1 amu ~1/1836 amu• AMU = atomic mass unit = 1/12 CARBON ATOM• (standard)

Page 36: Honors Biology Chapter 2
Page 37: Honors Biology Chapter 2

Neutral Atoms (no charge) (as seen on the periodic table)

• 39 Mass Number p + n K Symbol

• 19 Atomic Number p• (electrons = number of protons)• Neutral if negative charges = positive )

• n=mass no. – at.no.

Page 38: Honors Biology Chapter 2

How can you tell the mass number and atomic number?

Page 39: Honors Biology Chapter 2

When looking on the periodic table…

• Atomic Number• In order

• Identify element by its number of protons

• Mass Number• A decimal (average

of masses of all isotopes of that element)

Page 40: Honors Biology Chapter 2

Why is the mass number a decimal?

Average of the Isotopes of Carbon• What is the mass

number decimal?• 12.011

• What would you round it to?

• 12

Page 41: Honors Biology Chapter 2

What is the atomic number of?

• Silicon fluorine sodium WHY?

• 14 9 11• Number in succession (not

a decimal)• Number of protons

Page 42: Honors Biology Chapter 2

What is the mass number of…?

• Carbon nitrogen hydrogen• WHY?

• 12 14 1• Decimal number on periodic

table• Not other number in succession• Number of p + n

Page 43: Honors Biology Chapter 2

How do you find the number of…?• Protons electrons neutronsAtomic atomic mass number

number number minus atomic no.

(if neutral)

Page 44: Honors Biology Chapter 2

How many?• Protons electrons neutrons

• Carbon

6 6 6

• Chlorine

• 17 17 18

Page 45: Honors Biology Chapter 2

What is the atomic number?Mass Number?

• Number of p?

• Number of e-?

• Number of n?

Page 46: Honors Biology Chapter 2

Do Atomic Mass and Atomic Number WORKSHEET

•Collaborate with your partner next to you, then we’ll see what’s right.

Page 47: Honors Biology Chapter 2

ISOTOPES INTRO

• Isotopes (Virtual School) (2:51)

• Watch the video and list what facts you learned about isotopes.

• No, not about the Albuquerque Isotopes

Page 48: Honors Biology Chapter 2

Isotope• Atoms that differ in number of neutrons• Also differ in mass number(since it is p + n)

• But all have the same number of protons

Page 49: Honors Biology Chapter 2

Isotope Examples

• What are isotopes? (7:56)

Page 50: Honors Biology Chapter 2

Which is the most common isotope of Li? (check the

periodic table)

Page 51: Honors Biology Chapter 2

Why is the Mass Number a Decimal?

• Finding the Average Atomic Mass (2:55)

• Watch this and find out how…

Page 52: Honors Biology Chapter 2

How do you write chemical notation for isotopes?

Page 53: Honors Biology Chapter 2

2.4 Radioactive Isotopes

• An isotope that decays spontaneously to emit (give off) particles or energy until it is stable

• Here a radioisotope is used to examine a thyroid gland

• Radioactive Tracers in Medicine (3:57)

Page 54: Honors Biology Chapter 2

Radioactive Decay Examples

Page 55: Honors Biology Chapter 2

Uses of Radioisotopes• C-14 dating (can date living things up to

6,000 years old) Carbon Dating (2:00 mins)

• Technetium 99 Radioisotope (2:58) • Nuclear Medicine: What to expect (2:46 mins)• Bozeman Biology Radioactive Dating (9 mins)• Carbon-14 Dating (2 mins)

Thyroid tumorHighlight parts of the body for diagnosis

PET SCAN: detect tumors, weak spots in arteries

Page 56: Honors Biology Chapter 2

Uses of Radioisotopes

• Iodine-131 PIB molecule to

treat thyroid cancer detect Alzheimers

PET scan

Page 57: Honors Biology Chapter 2

Negative Effects of Nuclear Radiation

• Chernobyl Nuclear Plant Accident

Page 58: Honors Biology Chapter 2

Negative Effects of Radon

• Radon, a radioactive gas, causes lung cancer

• Found in regions containing uranium

Page 59: Honors Biology Chapter 2

2.5-2.7 Chemical Bonds

Page 60: Honors Biology Chapter 2

Ion• Charged atom

• Differs in number of electrons

• 39 Same mass number

K+ means lost one electron

• 19 Same atomic number

Page 61: Honors Biology Chapter 2

ION

• Charged atom• Na+ (has lost one electron)• O-2 (has gained two electrons)• Shown with superscript +/- and

number on upper right• (can omit number if a “1”)• What's and Ion? Youtube (6:52)

Page 62: Honors Biology Chapter 2

Ions form by gaining or losing electrons

Page 63: Honors Biology Chapter 2

O-2 has gained two electrons

Na has lost an e- so it is Na+1

Page 64: Honors Biology Chapter 2

Cation• Positive ion

• Na+

• Mg+2

• Lost electrons

Anion

• Negative ion

• Cl-

• O-2

• gained electrons

Page 65: Honors Biology Chapter 2

If one electron is…

• Lost what charge will the ion have?

•+1

11p+11 e-

11p+10e-

Page 66: Honors Biology Chapter 2

Which are ions?

• Cl O-2 Na+1 N2

Why?

• O-2 Na+1 • Charged atoms (lost or

gained electrons)• show charges as superscripts

Page 67: Honors Biology Chapter 2

Valence Electrons

• Outer shell electrons

• Determines the bonding capacity of an atom

Page 68: Honors Biology Chapter 2

How do electrons arrange themselves in an atom…

• In the outer electron shells (energy levels)?

• They are full with 2, 8, 8• Fill inner shell first, then go to next shell out(Outermost shell has the greatest energy)

Can you see any pattern how the e- arrange themselves?

Page 69: Honors Biology Chapter 2

Get kinda complicated beyond 2,8,8…so that’s all we’ll do for now!

Page 70: Honors Biology Chapter 2
Page 71: Honors Biology Chapter 2

Which electrons determine…

• The chemical properties of the atom?

• Outermost shell

Page 72: Honors Biology Chapter 2

If one electron is gained…

• What charge will the ion have?

•-1

Page 73: Honors Biology Chapter 2

• If 2 electrons are lost… What charge will the ion have?

•+2• If two electrons are gained…

What charge will the ion have?

•-2

Page 74: Honors Biology Chapter 2

Filled outer e- shells

How many e- fill the first shell (nearest the nucleus)?How many e- fill the next two shells?

nucleus

Page 75: Honors Biology Chapter 2

Gain 1 e- or lose 7 e-?

If gains 1 e-, then it becomes -1

Page 76: Honors Biology Chapter 2

Gain 7 e- or lose 1 e-?

If loses 1 e-, the it becomes +1.

Page 77: Honors Biology Chapter 2

Gain or Lose ?

If it could as easily lose or gain e-, then it will probably share them. It will form a covalent bond.

Tutorial 2.1 Chemical Bond Formation

Page 78: Honors Biology Chapter 2

Fill in the chart of e-

Element Number of e-

First shell Second Third

Shell Shell

carbon 6

lithium 3

Sodium 11

Oxygen 16

Page 79: Honors Biology Chapter 2

Fill in the chart of e-

Element Number of e-

First shell Second Third

Shell Shell

carbon 6 2 4

lithium 3 2 1

Sodium 11 2 8 1

Oxygen 8 2 6

Page 80: Honors Biology Chapter 2

How are ion charges determined?• Cation = positive (+) ion

• Anion = negative (-) ion

Page 81: Honors Biology Chapter 2

How are ion charges determined?

• If lose 1 e- = +1 charge

• If gain 1 e- = -1 charge

• If lose 2 e- = +2 charge

• If gain 2 e- = -2 charge

Page 82: Honors Biology Chapter 2

Periodic Table Hint:

• You can tell how many electrons are in an atom’s outermost shell by just looking at its position on the periodic table!!!!!

Page 83: Honors Biology Chapter 2

Note any pattern of valence electrons (outer shell) as they appear in the periodic table?

Page 84: Honors Biology Chapter 2

+1 +2

share -3 -2 -1 0

e- in outer shells

Ion formed

e- in outer shell

Full outer e- shells

H

8

Page 85: Honors Biology Chapter 2

How many electrons in each shell?(atomic number is given)

• Carbon oxygen fluorine sodium

• 12 16 9 11

• 2,4 2,6 2,7 2,8,1

Page 86: Honors Biology Chapter 2

How many valence electrons?Will these atoms lose or gain e-

and how many?

Page 87: Honors Biology Chapter 2

How many valence electrons?Will these atoms lose or gain e-

and how many?

Lose 1 lose O lose 1 share gain 3 lose 1

H+ He Li+ C N-3 Na+

Page 88: Honors Biology Chapter 2

Now let’s do the Drawing Atoms Worksheet(and next 4 slides)

• How the electrons fill their shells (link)

• 1st shell – 1 pair• 2nd shell – e- space

far apart, singles, then pair

• 3rd shell – e- space far apart, singles, then pair

Page 89: Honors Biology Chapter 2

Bohr Diagrams

C

1) Draw a nucleus with the element symbol inside.

2) Carbon is in the 2nd

period, so it has two energy levels, or shells.

3) Draw the shells around the nucleus.

Page 90: Honors Biology Chapter 2

Bohr DiagramLet’s do carbon (6 electrons)

• 1. Draw a nucleus.

• 2. Draw the number of rings needed.

• 3. Start in the first shell- only 2 e-, paired (put next to each other)

C

Get worksheet

Page 91: Honors Biology Chapter 2

Bohr Diagrams

1) Since you have 2 electrons already drawn, you need to add 4 more.

2) These go in the 2nd

shell.3) Add one at a time -

starting on the top and going counter clock-wise.

C

1

2

3

4

Page 92: Honors Biology Chapter 2

Bohr Diagrams

If you were to have more electrons, start pairing them in the same clockwise order.

1

2

3

4

5

6

1

2

3

4

5

6

Page 93: Honors Biology Chapter 2

Bohr model electron filling order

2

Page 94: Honors Biology Chapter 2

Are these correct Bohr models?

Page 95: Honors Biology Chapter 2

Are these correct Bohr models?

• What errors are at the ?

Page 96: Honors Biology Chapter 2

Now do on the Atomic Structure Worksheet

Page 97: Honors Biology Chapter 2

See the trend of how electrons fill the valence shells

• Lewis dot structures

• Octet Rule – electrons fill a shell until it’s full with 8 electrons

• Atoms are most stable with a filled outer electron shell

Page 98: Honors Biology Chapter 2

What do we call the forces that…

• Hold atoms together in a molecule?

• Chemical bonds

• …not to be confused with James Bond

Page 99: Honors Biology Chapter 2

Why do atoms bond?

•To have filled outer electron shells!

•Atom Heaven ATO

M

Page 100: Honors Biology Chapter 2

What is a chemical bond?

• Attraction between two or more atoms YouTube - ?Ionic and covalent bonding animation??

Page 101: Honors Biology Chapter 2

Get Bonding Handouts

• Electronegativities

• Intermolecular Forces

• Bonding Reference Sheet

Page 102: Honors Biology Chapter 2

Types of Bonds

Intramolecular

• Within the molecule

• -Ionic• -Covalent• Polar• Nonpolar

Intermolecular

• Between different molecules

• Van der Waals• London forces• Dipoles• Hydrogen Bonds

Page 103: Honors Biology Chapter 2

Bonding

• Covalent

• share electrons

• Ionic• transfer of

electrons

• (lose or gain)

Page 104: Honors Biology Chapter 2

IONIC BOND

• lose one or more electrons become (+)

• gain one or more electrons become (-)

• The (+) and (-) ions formed now attract each other and form an ionic bond.

Page 105: Honors Biology Chapter 2
Page 106: Honors Biology Chapter 2

Covalent Bonds

• Polar Covalent

• Unequal sharing of e-

• Nonpolar Covalent

• Equal sharing of e-

Page 107: Honors Biology Chapter 2

Covalent BondsClick HERE: Polar Covalent

Bonding (3 animations)•Electrons are shared

•Usually if near the same number of e- in outer shells

Page 108: Honors Biology Chapter 2

Covalent bonding can be shown as:

• Bohr model

• Electron-dot

• Structural Formula

Page 109: Honors Biology Chapter 2

How can covalent bonds be written?

• Single bond double bond triple bond

• C-C C=C C=C• C:C C::C C:::C

• 2 e- 4 e- 6 e-

Page 110: Honors Biology Chapter 2

Writing Bonds• Each “ Each “ ––” ” is equal tois equal to

• “ “ :: “ or “ or

• ““two electronstwo electrons””

Single C – C or C:CDouble C = C or C::CTriple or C:::CC≡C

Page 111: Honors Biology Chapter 2
Page 112: Honors Biology Chapter 2

Different Ways to Represent Four Common Molecules

butane

Page 113: Honors Biology Chapter 2

Making ionic bond in NaCl

• YouTube - ?Ionic and covalent bonding example??

• YouTube - ?Reaction of Sodium & Chlorine (with subtitles)??

Page 114: Honors Biology Chapter 2

SALT =

• Synonym for an ionic compound

• Not just NaCl

Iron SulfideCopper Sulfate

Sodium chloride

Page 115: Honors Biology Chapter 2

LET’S REVIEW: Which atoms combine…

• with other atoms?

• Ones that do not have filled outer electron shells

Page 116: Honors Biology Chapter 2

REVIEW: What is the driving force to make atoms join with

other atoms to form compounds?

• TO HAVE FILLED OUTER ELECTRON SHELLS

Page 117: Honors Biology Chapter 2

REVIEW: How does an atom…

• Get a filled outer electron shell?

• Gaining, losing, or sharing electrons

Page 118: Honors Biology Chapter 2
Page 119: Honors Biology Chapter 2

What do you notice about the ion charge and the subscripts?

Page 120: Honors Biology Chapter 2

Do the Flip-Flop

• So you can cancel out the (+) and (-)

Page 121: Honors Biology Chapter 2

If there is only one atom, you do not need to write a “1”

You can reduce the subscripts if they are the same:

Fe+2 O-2 Fe2O2 reduce to FeO

Page 122: Honors Biology Chapter 2

Electronegativity

•Get Electronegativities handout

Page 123: Honors Biology Chapter 2

Electronegativity

Tendency of an atom to attract electrons towards itself and thusthe tendency to form negative ions.

Page 124: Honors Biology Chapter 2

Electronegativity• The more electronegative

atom pulls shared electrons toward its nucleus.

• NONPOLAR – equal sharing of electrons

• POLAR – unequal sharing

of electrons

Page 125: Honors Biology Chapter 2

Electronegativities

• H = 2.1 O=3.5 C=2.5• H-H = 0.0 bond pure covalent• O-H bond = 1.4 polar • (3.5-2.1)• covalent• NaCl = 2.1 ionic

Page 126: Honors Biology Chapter 2

Molecule

• A group of two or more atoms held together by covalent bonds

Page 127: Honors Biology Chapter 2

What’s the difference between Intramolecular

and Intermolecular Forces?

Page 128: Honors Biology Chapter 2

What’s the difference?• Intermolecular

attractions are between one molecule and a neighboring molecule

• (Van der Waals, hydrogen bonds)

• USUALLY WEAKER

• Intramolecular attractions are the forces which hold an individual molecule together (for example, the covalent bonds or ionic bonds).

• USUALLY STRONG

Page 129: Honors Biology Chapter 2

WHAT IS THE STRENGTH COMPARISON?

• STRONGEST BOND

• WEAKEST BOND

• Covalent

• Ionic

• Hydrogen

• Van der Waals• (dipole-dipole• London forces)

intramolecular

Page 130: Honors Biology Chapter 2

INTERMOLECULAR FORCES

• A. H-bonds (H to F, O, or N)

• B. van der Waals- temporary “dispersion” London (nonpolar) and dipole-dipole forces (polar)

• C. Disulfide bridges (-S-S-)• Intermolecular Forces Youtube (9:11-if ya got time)

Page 131: Honors Biology Chapter 2

• Intermolecular Forces

video and worksheet• What three types of intermolecular forces are there?• What does dipole mean? Why do those molecules

attract each other?• London forces are in molecules that are not dipoles.

What do they do to their e- to cause an attraction?• What three possible atoms can make a hydrogen bond

with hydrogen?• List the forces in order of strength.

Page 132: Honors Biology Chapter 2

Hydrogen Bonds: Intermolecular between H and F, O, or N

Page 133: Honors Biology Chapter 2

Where Might you find Hydrogen Bonds?

• In Water – between O- and H+

• In DNA – between bases

Page 134: Honors Biology Chapter 2

Intramolecular: Van der Waals

• Van der Waals on Gecko Feet (8:22)

• Is the sum of the attractive forces between molecules (but not H-bonds or covalent bonds)

Page 135: Honors Biology Chapter 2

van der WaalsVan der Waals Dispersion Forces

Temporary dispersion of electrons make temporary charges

Page 136: Honors Biology Chapter 2

Where might you find van der Waals?

• crystal structures (e. g. the shapes of snowflakes),

• DNA shape

Page 137: Honors Biology Chapter 2

Intramolecular: (Van der Waal type) Dipole-dipole

• exists between neutral polar molecules only when they are close together

• Dipole Forces Bozeman youtube (7:32)• Temporary shift of the electrons to make a

partial + and a partial - end

Page 138: Honors Biology Chapter 2

Weakest van der Waals:London Dispersion Forces

• Temporary polarity between nonpolar atoms or molecules

• All molecules have them at some time• Bozeman London Dispersion Forces (5:02)

Page 139: Honors Biology Chapter 2

London Dispersion ForceLondon Dispersion Force Animation

Page 140: Honors Biology Chapter 2

Disulfide Bonds:Protein Tertiary Structure

• Disulfide Bond in Tertiary Protein

Page 141: Honors Biology Chapter 2

Disulfide Bonds

• formed between the side chains of cysteine in a protein SH) to form a disulfide bond (S-S)

• (Will learn about this in Chapter 3)

Page 142: Honors Biology Chapter 2

THEME OF EMERGENT PROPERTIES

• New properties that arise with each step upward in the hierarchy or life, owing to the arrangement and interactions of parts as complexity increases.

• WHOLE IS GREATER THAN THE PARTS

Page 143: Honors Biology Chapter 2

How is the emergent property idea apply to a compound and atoms?

• HINT:

Page 144: Honors Biology Chapter 2

2.9 Chemical Reactions

• The making and breaking of chemical bonds, leading to changes in the composition of matter.

Page 145: Honors Biology Chapter 2

Chemical Reactions

• Reactants on the left of the arrow

• Products on the right of the arrow

• IDENTIFY:

• 2Mg(s)  +  O2(g)  →    2MgO(s)

• MgO(s)  +   H2O(l)  →    Mg(OH)2(s)

• N2(g)  +  3H2(g)  →    2NH3(g)

Page 146: Honors Biology Chapter 2

Same number of each element on left side as on the right side

• CH4 (g) + 2O2 (g) CO2 (g) + 2H2O (g)

Reactants Products

C = 1

H = 4

O = 4

C = 1

H = 4

O = 4

Page 147: Honors Biology Chapter 2

Signs of a Chemical Reaction

• Precipitate forms

• Color Change

• Gas Forms

• Temperature change

Page 148: Honors Biology Chapter 2

Chemical Reaction Videos

• Na and Cl Chemical Rx (52 secs.)

• Genie in a Bottle Reaction - Steve Spangler (3:36)

• Weirdest Chem. Rx in the World (2:52) Mercury(II) thiocyanate Hg(SCN)2

• The Naked Scientists Videos (MP3)

Page 149: Honors Biology Chapter 2

Chemical Reaction Example

• An iron bar rusts. The iron reacts with oxygen in the air to make rust.

4 Fe + 3 O2 2 Fe2O3