Download pptx - Ch2 notes 2013

Transcript
Page 1: Ch2 notes 2013

Chemistry of LifeChapter 2

Page 2: Ch2 notes 2013

2.1 Nature of MatterOrganisms are chemical machines All organisms consist of atoms

– Subatomic particles Electron (e-) – located in electron cloud Proton (p+) – located in the nucleus Neutron (no) – located in the nucleus

Oxygen atom (O)

Nucleus:8 protons (+)8 neutrons

outermost energy level: 6 electrons (-)

inner energy level: 2 electrons (-)

Page 3: Ch2 notes 2013
Page 4: Ch2 notes 2013

Elements– Differ in the number of protons in

the nucleus.– Number of protons = Number of

electrons Elements are neutral on the periodic table

– Atomic Number = Number of protons– Atomic Mass = Number of protons +

Number of neutrons

http://www.privatehand.com/flash/elements.html

Page 5: Ch2 notes 2013

Using the Periodic Table, Complete the following:

Name Symbol # p+ # e- #no

Tin

25

N

15

12

Page 6: Ch2 notes 2013

Isotopes Differ in the number of neutrons they

contain in the nucleus– Example:

Carbon 12 – 6p+, 6e-, 6no

Carbon 13 – 6p+, 6e-, 7no

Carbon 14 – 6p+, 6e-, 8no

Page 7: Ch2 notes 2013

Chemical Bonding – Compounds are made of joined atoms of two or more different elements.

Valence shell – outermost electron shell– Atoms with a full valence shell are inert

(unreactive)– Atoms without a full valence shell can form

bonds (reactive).

Page 8: Ch2 notes 2013

Complete the following table and answer the question in your notebook:

Name Symbol # p+ # e- #no

Oxygen

6

K

53

- Why do all isotopes of an element have the same chemical properties? (Use your book to help you answer this)

Page 9: Ch2 notes 2013

Bohr Atom Models The first electron shell of every atom

can hold a maximum of 2 electrons. Each additional shell can hold a

maximum of 8 electrons.

Page 10: Ch2 notes 2013

Draw the electron configurations of an atom of the following elements:

1. Fluorine

2. Boron

3. Sodium

Page 11: Ch2 notes 2013

Covalent bonds – atoms share electrons

– Ex: H2, O2, CO2

covalent bonds

Oxygen atom (O) Carbon atom (C) Oxygen atom (O)

Carbon dioxide (CO2 )

Page 12: Ch2 notes 2013

Ionic Bonds Ionic Bonds – atoms gain or loose

electrons– Atoms form ions + charge – cation - charge – anion

Ex: NaCl

Page 13: Ch2 notes 2013

2.2 Hydrogen Bonds Hydrogen Bonds – weak chemical

attraction between polar molecules– Water is a polar molecule because the

electrons of O and H are shared unequally.

Page 14: Ch2 notes 2013

Cohesion

Page 15: Ch2 notes 2013

2.3 Carbon Compounds• 70% of your body is made of water.• The remaining 30% is made up

mostly of organic compounds (Carbon-based molecules).– Carbon is a unique element because it

forms four covalent bonds and can form a lot of different structures.

Page 16: Ch2 notes 2013

Many carbon-based molecules are made of many small subunits bonded together.– Monomers are the individual subunits.– Polymers are made of many monomers.

Page 17: Ch2 notes 2013

Carbohydrates Key source of energy found in

most foods Fruits, vegetables, and grains

Made up of single sugars called monosaccharides.

Glucose, fructose

Disaccharides - two monosaccharides are joined

Sucrose (table sugar)

Polysaccharides – chains of three or more monosaccharides

Starch, cellulose, glycogen

Page 18: Ch2 notes 2013

Polymer (starch)

Starch is a polymer of glucose monomers that often has a branched structure.

Polymer (cellulose)Cellulose is a polymer of glucose monomers that has a straight, rigid structure

monomer

Page 19: Ch2 notes 2013

Lipids Nonpolar molecules not soluble in

water Fats, phospholipids (make up the cell

membrane), steroids (cholesterol), waxes Saturated fatty acids

Solid at room temperature Butter, lard, grease

Unsaturated fatty acids Liquid at room temperature Olive oil, fish oil

Page 20: Ch2 notes 2013
Page 21: Ch2 notes 2013

Proteins Formed by chains of linked amino

acids Many functions including:

Enzymes Structural (imbedded in the cell membrane) Antibodies

Page 22: Ch2 notes 2013

Nucleic Acids Formed by chains of nucleotides

Two types : DNA (deoxyribonucleic acid)

Double strand of nucleotides Stores hereditary information

RNA (ribonucleic acid) Single strand of nucleotides Plays a key role in making proteins

Nucleotide

Page 23: Ch2 notes 2013
Page 24: Ch2 notes 2013

Another important biological moleculeATP (adenosine triphosphate)

– Consists of a single nucleotide with 2 extra phosphate groups.

– ATP stores energy temporarily.– All cells require ATP to function.

Page 25: Ch2 notes 2013

2.4 Chemical Reactions Chemistry allows life to function!

Everything living things do is possible due to chemical reactions

The chemistry of breathing

Page 26: Ch2 notes 2013

Chemical reactions release or absorb energy.

Activation energy is the amount of energy that needs to be put in to start a chemical reaction.

Page 27: Ch2 notes 2013

Exothermic reactions release more energy than they absorb.– Excess energy is released by the reaction

as heat.

Page 28: Ch2 notes 2013

Endothermic reactions absorb more energy than they release.– Energy is absorbed by the reaction.

Page 29: Ch2 notes 2013

Enzymes– Proteins that increases the speed of a

chemical reactions in cells– Act as a catalyst (reduces the activation

energy needed in a reaction)

Page 30: Ch2 notes 2013

Any factor that changes the shape of an enzyme can affect the enzyme’s activity.– An enzyme’s function depends on its

structure.– Denaturing (changing the structure) the

protein by changes in temperature or pH– Example: pepsin


Recommended