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Matter –Anything that has mass and occupies space

•1 The basic unit of matter is called the atom.

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Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14

6 electrons6 protons6 neutrons

6 electrons6 protons8 neutrons

6 electrons6 protons7 neutrons

Section 2-1

Figure 2-2 Isotopes of Carbon

•2, 3 Atomic Nuclei contain protons and neutrons.•Protons 1+ charge size 1 amu nucleus•Neutrons 0 charge size 1 amu in nucleus•Electrons 1- charge size 1/1840 amu in electron cloud

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4 Atoms are neutral because they contain the same # of electrons & protons.

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5 Chemical elements are groups of atoms having the same atomic number, that is, atoms having the same

number protons.

These are all atoms of Carbon. All have atomic # 6.

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6

C12.011

Section 2-1

An Element in the Periodic Table

•6. Proton # = 6 : shown by the atomic number• •Also, C atoms have 6 electrons: Since atoms are neutral, if you know proton #, you also know electron #!

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Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14

6 electrons6 protons6 neutrons

6 electrons6 protons8 neutrons

6 electrons6 protons7 neutrons

Section 2-1

Figure 2-2 Isotopes of Carbon

•7 Isotopes are forms of the same element that have the same number of protons but a different number of neutrons.

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Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14

6 electrons6 protons6 neutrons

6 electrons6 protons8 neutrons

6 electrons6 protons7 neutrons

Section 2-1

Figure 2-2 Isotopes of Carbon

8 Isotopes are identified by isotopic notation:• Carbon-12, carbon-13, carbon-14 OR• 12C 13C 14C• 6 6 6

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9 Isotopes of the same element have the same properties because they have the same atomic

number (the same number protons)

• 12C

13C

14C

• 6 6 6

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10 Chemical compounds are groups of atoms held together by chemical bonds. Chemical compounds are more stable than individual

atoms (except for noble gas atoms which have stable ---filled—valence electron shells.

•Chemical compounds allow atoms to obey the “octet rule”. (2 electrons in the outer electron shell in H and He, but 8 for other elements.

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11 Chemical formulas show the numbers of different kinds of atoms bonded together in a single formula unit of

a compound

•NaCl one Na ion bonded to one Cl ion•Why do we know it’s composed of ions? Because Na is a metal—an electron donor—and Cl is a nonmetal—an electron acceptor if a metal is present to give it an electron.

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12 Atoms in compounds are held together by chemical bonds—either ionic or covalent.

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Sodium atom (Na) Chlorine atom (Cl)

Sodium ion (Na+) Chloride ion (Cl-)

Transferof electron

Protons +11Electrons -11Charge 0

Protons +17Electrons -17Charge 0

Protons +11Electrons -10Charge +1

Protons +17Electrons -18Charge -1

Section 2-1

Figure 2-3 Ionic Bonding

13 Ionic bonds: attraction of negative ions to positive ions because a metal donates its electrons to a nonmetal atom, forming stable ions with complete valence shell octets.

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13 Covalent bonds form when nonmetal atoms share electrons to fill their valence octets, linking atoms because both nuclei attract

the shared electrons.

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Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-)

Transferof electron

Protons +11Electrons -11Charge 0

Protons +17Electrons -17Charge 0

Protons +11Electrons -10Charge +1

Protons +17Electrons -18Charge -1

Section 2-1

Figure 2-3 Ionic Bonding

14 Ions are atoms carrying a charge after losing or gaining valence electrons.

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15. False. Atom that loses electrons becomes a positive ion.

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16 Molecules (Not ionic compounds!) form when atoms are joined with covalent

bonds.

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17 A is false—2 shared electrons is a single covalent bond

A

C

b

•D covalent bonds are formed when atoms share electrons

http://academic.brooklyn.cuny.edu/biology/bio4fv/page/covalent_bonds.html

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18 Van Der Waals forces and dipole-dipole interactions hold atoms of nearby molecules together.

•Occasionally, valence electrons are nearer one atom than the other in a covalent bond, creating areas partial charge.

http://www.chem.unsw.edu.au/coursenotes/CHEM1/nonunipass/HainesIMF/images/dipoledipole.jpg

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Lesson 3: Chapter 2 The chemistry of Life

1. Watch movie on water, then answer questions on the worksheet together in your lab group BEFORE beginning the lab. Teacher will select one worksheet for grading, by random drawing.

2. Complete water lab, then turn in one copy per lab group . Teacher will select one student’s report.

3. Discuss the water movie & labs, and complete the 2.2 guided reading questions 1—8 as a class.

• Homework: guided reading & study workbook questions, pages 15—16, #9—21.

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• 2–2 • Properties of Water,

• the strangest and most important molecule on earth!

Section 2-2

Section Outline

http://www.wsi.nrcs.usda.gov/products/images/wq_drop.jpg

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http://www.sumanasinc.com/webcontent/animations/content/propertiesofwater/water.html

Watch this movie from beginning to end.Then, the teacher will advance the movie one question at a time, giving time for you to write the answers to each question.

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Guided reading & study workbook for section 2.2, p 15--16

1. Water molecules contain 10 electrons, 1 for each H and eight for O. Water molecules also contain 10 protonsTrue or False. Water molecules are neutral.

1.True2.False

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2. Because water molecules have O at one end and H at the other, the entire molecule:

1.Is positively charged2.Is negatively charged3.Is polar, with partial +

& - charges.

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3. Water is a polar covalent molecule because:1.More electronegative O atoms are bonded to

less electronegative H atoms2.O carries a δ- charge & H’s a δ+ charge3.The shared electrons of each O—H covalent

bond are more strongly attracted to the O4.All of the above5.None of the above

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• Strongest triple covalent bond• 2nd strongest double covalent bond• 3rd strongest single covalent bond• 4th strongestionic bond• 5th strongestHydrogen bonds• 6th strongestDipole dipole interactions (polar

molecules attracted δ+ to δ- )OTHER than Hydrogen bonds

• 7th strongest Van der Waals forces (hydrophobic• interactions of nonpolar compounds)

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4. Which statement is True?

1.Hydrogen bonds are stronger than ionic bonds.2.Attraction of the H in one water molecule to O in

another is a Hydrogen bond3.Hydrogen bonds are stronger than covalent bonds4.Hydrogen bonds are the strongest bonds BETWEEN

different neutral molecules.5.Choices 2 and 5 are true

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cohesion

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5. Cohesion is:

1.Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder

2.Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules

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5. Adhesion (exhibited by water adhering to the spider web) is:

1.Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder

2.Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules

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6. Water is cohesive (shown by water’s forming droplets) because:1.δ+ H and δ- O atoms of water

molecules are attracted to each other in the same molecule

2.δ+ H and δ- O atoms of water molecules are attracted to each other in adjacent molecules

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Surface tension versus capillary action

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7. The rise of water in a narrow tube (like water rising in a thermometer) against the force of gravity is:1.surface tension2. capillary action3. specific heat

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8 In plants capillary action:1. Draws water upwards from the roots

into the leaves through thin tubes called xylem

2. Pulls sugar downwards from the leaves into the roots through thin tubes called phloem

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10-1-09Lesson on solutions and suspensions with homework

correction slidesLesson on acids and bases

Complete water labs & questions & acid/base questions. Tear off lab & questions through end page. Put rest back in notebooks.

Homework: prep for a quiz on ch 2.1,2.2, tomorrow

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Mixture: 2 or more substances combined but not chemically bonded. They can be separated without another chemical reaction (a physical separation).

e.g., sand and water can be separated with a filter inks in markers can be separated with

chromatographySalt can be removed from water by evaporating the

water

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9. True or False. Sucrose (C6H12O6) is a mixture.

50%50%1. True2. False

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9. True or False. Sucrose (C6H12O6) dissolved in water is a mixture.

50%50%1. True2. False

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Mixtures may be heterogenous (nonuniform throughout) or homogenous (uniform throughout)

Another name for a homogeneous mixture is solution.Another name for a heterogeneous mixture is suspension.

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10. This picture shows bananas mashed up in water. This mixture is a

susp

ension

solution

50%50%

1.suspension2.solution

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11. World’s greatest solvent: water!• Water is known as the universal solvent because it

can dissolve ionic compounds and polar covalent compounds.

• Ionic and polar covalent compounds are hydrophillic (water loving)

• Water can not dissolve nonpolar covalent compounds.

• Nonpolar compounds are hydrophobic (water hating)

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12. A suspension is a:

Homogeneous m

i...

Hetero

geneous .

..

Unsta

ble (part.

..

Stable (a

solu...

2 and 3

20% 20% 20%20%20%

1. Homogeneous mixture2. Heterogeneous mixture3. Unstable (particles settle out

over time)4. Stable (a solution whose

solutes do not settle out)5. 2 and 3

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Parts of Solutions:Solvent: more abundant—does the dissolving

Solute: less abundant—gets dissolved

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13. Two liters water are mixed with 0.3 liters salt. The water is the

solution

solute

solve

nt

33% 33%33%

1. solution2. solute3. solvent

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14. Two liters water are mixed with 0.3 liters salt. The salt is the

solution

solute

solve

nt

33% 33%33%

1. solution2. solute3. solvent

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concentration

Molarity (M) = # moles solute/#L solution

3 Moles/0.5 L = 6 M

1 mole NaCl = 58.4 g29.2 g/0.25 L = 0.5 moles/0.25 L= 2M

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Aqueous solutions can be neutral, acidic, or basic.

These descriptions depend refer to the behavior of the solute when it is dissolved in water and to how this behavior alters the molar concentrations of these two ions in the aqueous solution:

H+ protons OH1- hydroxide ions

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1 out of over 500 million water molecules dissociates to H+ hydronium, OH- hydroxide

Neutral aqueous solutions and pure water contain equal numbers of both ions.

2H2O(l) → H3O+(aq) + OH–

(aq)

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14. Two water molecules can react to form:

Nonpolar

compo...

Hyd

ronium &

hy...

50%50%2H2O(l) → H3O+(aq) + OH–

(aq)

1. Nonpolar compounds

2. Hydronium & hydroxide ions

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15. Water is neutral because it:

Is polar c

oval...

Form

s Hydro

gen...

Has e

qual numb...

Is nonpolar c

o...

25% 25%25%25%

1. Is polar covalent2. Forms Hydrogen bonds3. Has equal numbers of

hydronium & hydroxide ions

4. Is nonpolar covalent

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Acids increase the H1+ content of water in aqueous solutions. Bases increase the OH1-

HCl H+ + Cl-

NaOH Na1+ + OH1-

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Oven cleaner

Bleach

Ammonia solution

Soap

Sea water

Human bloodPure waterMilkNormalrainfall

Acid rainTomatojuice

Lemon juice

Stomach acid

NeutralIn

crea

sing

ly B

asic

Incr

easi

ngly

Aci

dic

Section 2-2

pH Scale

The more H+ ions, the more acidic, the lower pH.

The more OH1-

ions, the more basic, the higher pH.

pH measures whether either H+ ions are greater (acidic) or the OH1- ions are greater (basic)

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16. The pH scale indicates:

The acidity

of...

The basicity

o...

The conce

ntrat..

.

All of t

hese.

25% 25%25%25%

1. The acidity of an aqueous solution

2. The basicity of an aqueous solution

3. The concentration of H+ ions present relative to concentration of the OH- ions

4. All of these.

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17. Which of these aqueous solutions is most acidic?

pH9 pH11

pH7 pH5

pH3

20% 20% 20%20%20%

1. pH92. pH113. pH74. pH55. pH3

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Oven cleaner

Bleach

Ammonia solution

Soap

Sea water

Human bloodPure waterMilkNormalrainfall

Acid rainTomatojuice

Lemon juice

Stomach acid

NeutralIn

crea

sing

ly B

asic

Incr

easi

ngly

Aci

dic

Section 2-2

pH Scale

pH 7 has 10 times less H+ than pH6 and 100 times less than pH5

The pH scale is logarithmic.

So, pH 0 has 10 times more H+ than pH1 and 100 times more than pH2.

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18. How many more H+ ions does a solution with pH 4 have than one with pH 5?

1X more

10X more

100X more

It has 1

X less.

..

25% 25%25%25%

1. 1X more2. 10X more3. 100X more4. It has 1X less than

pH5

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19. Which statement is false?

Acidic

solution pH is

< 7

Acids a

dd H+ to so

lutions

Stro

ng acid

s make

solut..

.

Acidic

solutions h

ave hi...

25% 25%25%25%

1. Acidic solution pH is < 72. Acids add H+ to solutions3. Strong acids make solutions whose

pH is 11--144. Acidic solutions have higher

concentrations of H+ than pure water