Daily Practice 10/13/091. What could you do different this quarter

to improve your grade vs. 1st quarter?2. What should you do if you miss an

assignment? How many days do you have to complete it?

3. Who’s responsibility is it to make up tests/quiz/assignments?

4. Turn in any makeup/late work into the tray before the bell rings!!!!!!!!!!!!!!!!!

Ch. 2 The Chemistry of Life

Section 6.1

Atoms, Elements, and CompoundsObjectives•Identify the particles that make up atoms.•Diagram the particles that make up an atom.•Compare covalent bonds and ionic bonds.•Describe van der Waals forces.

Nature of Matter

• Chemistry is the study of matter.• Atoms – basic unit (building block) of

matter–100 million atoms side by side would

make a row about 1 cm long (width of a pinkie finger)

Nature of Matter–Subatomic particles that make up atoms

are:• Protons – positively charged•Neutrons – no charge, same mass as protons• Electrons – negative charge and in constant motion surrounding nucleus

–Nucleus – center of the atom that contains protons and neutrons

Nature of Matter• Atoms are Neutral –Atoms have equal number of electrons

and protons– Ex: O has 8e- and 8protons

8e- +8p+

0 charge–Atomic Number - # of protons in an atom of elements

Elements• Element – pure substance that consists

entirely of one type of atom–More than 100 elements are known–24 are commonly found in living

organisms–92 of which occur naturally.

O2Fe

NS

CaNa

Ne

Elements• Each element has a unique name

and symbol.• Usually 1 letter capitalized like C

for carbon• Some have 2 letters in this case

the second is lower case like in Ca for Calcium

• The periodic table is organized into:–horizontal rows, called periods–vertical columns, called groups.

• Each individual block in the grid represents an element.

• The table is called periodic because elements in the same group have similar chemical and physical properties.

Daily Practice 10/14/091. What does the atomic number tell you?2. What two subatomic particles must be

equal in a cell in order for it to be neutral?

3. What does the atomic mass tell you?4. How do you calculate the number of

neutrons?5. Just like yesterday find the Atomic #,

mass, number of neutrons, and make the electron configuration for Cu

Isotopes

• Isotopes – atoms of same element that differ in number of neutrons they contain– Isotopes are identified by mass number–Mass Number – sum of protons and

neutrons in nucleus of an atom

Isotopes– Isotopes – – Protium -1p and mass 1–Deutrium -1p and 1neutron and mass

2–Tritium – 1p and 2 neutrons and mass

3

– Isotopes have the same number of e-, all isotopes of elements have the same chemical properties

Radioactive Isotopes Nuclei are unstable

and break down at a constant rate over time.

UsesDetermine ages of

rocks and fossilsTreat cancer and kill

bacteria that causes food to spoil

Used as tracers to follow movements of substances with in organisms

When a nucleus breaks apart, it gives off radiation that can be detected and used for many applications

A pure substance formed when two or more different elements combine

Compounds are always formed from a specific combination of elements in a fixed ratio.

Compounds cannot be broken down into simpler compounds or elements by physical means.

H2O → 2:1→ 2:H and 1:ONaCl → 1:1 → 1:Na and 1:Cl

COMPOUNDS

Chemical Bonds• Ionic Bonds – formed when one or more

e- are transferred from one atom to another.

• That means there is an electrical attraction between two oppositely charged atoms or groups of atoms– Ion – positively and negatively charged

atoms

–Na Cl

• The elements identified as metals tend to donate electrons.

The elements identified as nonmetals tend to accept electrons.

Some atoms tend to donate or accept electrons more easily than other atoms.

Most ionic compounds are crystalline at room temperature and have higher melting points than molecular compounds formed by covalent bonds.

Chemical Bonds Conti. Covalent Bond – formed when e- are

shared between atoms.Atoms share 2e- = single covalent

bond H2O

Chemical Bonds Conti. Atoms share 4e- = double covalent bond

O2Atoms share 6e- = triple covalent bond

N2 Molecule – is a compound that

is held together with covalent bonds.

Diatomic Molecules – molecules are made of 2 of the same atoms

H2, O2, N2, F2,Cl2 , Br2, I2

Chemical Bonds Conti. Pg 155• Van der Waals Forces – slight attraction that

develops between oppositely charged regions of nearby molecules.–Van der Waals forces are not as strong as ionic

or covalent bonds, they can hold molecules together, especially when molecules are large.

– The strength of the attraction depends on the size of the molecule, its shape, and its ability to attract electrons.

Section 6.2

Chemical ReactionsObjectives•Identify the parts of a chemical reaction.•Relate energy changes to chemical reactions.•Summarize the importance of enzymes in living organisms.

Chemical Reactions and Enzymes Chemical Reaction – process that

changes one set of chemicals into another set of chemicals. (That is they are reorganized into different substances)

Ex: Fe + O2 → FeO2 (rust – slow process)

Ex: 2H2O → H2 + O2

Chemical Reactions and EnzymesClues that a chemical reaction has taken place include the production of heat or light, color change and formation of a gas, liquid, or solid.

Chemical Reactions and EnzymesReactant – elements or compounds

that enter into chemical reaction Ex: Fe + O2 and 2H2O

Product – elements or compounds produced by chemical reaction Ex: FeO2 and H2 + O2 Lab Demo – Baking Soda

Balanced EquationsThe law of conservation of mass states

matter cannot be created or destroyed.The number of atoms of each element on

the reactant side must equal the number of atoms of the same element on the product side.

Energy in Reactions Energy is released or absorbed when

chemical bonds form or break Chemical reactions releasing energy

occur spontaneously2H2 + O2 → 2H2OH gas burning with O2 = water vapor

with energy released in form of heat and if H explodes = light and sound

Humans release energy needed to grow, breathe, think, metabolize, break down food, or digest food

Energy in Reactions–Chemical Reactions absorbing energy will

not occur without source of energy• 2H2O → H2 + O2• Absorbs energy and must have electric current going through water• Plants get energy by trapping and storing energy from the sun• Animals get energy when they eat plants or animals that eat plants

–Activation Energy – energy needed to get reaction started• Lighting a match to burn trash

Energy in Reactions–Activation Energy – energy needed to

get reaction started• Lighting a match to burn trash

Energy in Reactions

This reaction is exothermic and released heat energy.

The energy of the product is lower than the energy of the reactants.

Energy in Reactions

This reaction is endothermic and absorbed heat energy.

The energy of the products is higher than the energy of the reactants.

Enzymes Catalyst – substance

that speeds up rate of chemical reaction or lowers reaction’s activation level It does not

increase how much product is made.

A catalyst is not used up in a reaction.

Enzymes Cont. Enzymes – proteins that act as biological

catalystsCells use enzymes to speed up

chemical reactions that take place in cells and lowers activation energy

P. 51 graphCarbonic anhydrase, enzyme in

bloodstream that speeds up reaction to remove CO2 (Carbon Dioxide) from blood

Enzyme Action For chemical reactions to occur then

reactants must collide with energy so bonds will be broken and new bonds formed

The reactants that bind to the enzyme are called substrates – (they help catalyzed reactants)Substrates (protein) that attach to

enzyme at active site and form an enzyme – substrate complex

Enzyme Action–The specific location where a substrate

binds on an enzyme is called the active site.–Proteins have a specific shape, so an

active site must be complementary–Compared to a lock and key model

The active site changes shape and forms the enzyme-substrate complex, which helps chemical bonds in the reactants to be broken and new bonds to form.

Enzyme Action–When complex is formed, enzyme helps

convert substrate into product until done and then they are released–Most cells contain proteins that turn

key enzymes on or off, along with pH and temperature•Human cells work best at 37⁰, human body’s core temperature

Section 6.3Water and Solutions

Objectives• Evaluate how the structure of water makes it a good solvent.•Compare and Contrast solutions and suspensions.•Describe the difference between acids and bases.

Properties of Water Water

Covers ¾ of EarthSingle most abundant

compound in most living things

Expands as it freezes and is less dense than liquid water explaining why it floats

Properties of Water Conti.• Water Molecules– H2O = 2protons H + 8protons O = 10 protons

2e- H + 8e- = 10e-10protons + 10 e- = 0 (neutral)

• Polarity–Water molecule is polar because there is uneven

distribution of e- between H and O2 atoms/• Between molecules is a magnet with poles• O2 end has negative charge and H end has + charge

Hydrogen Bonds• A hydrogen bond is a weak interaction

involving a hydrogen atom and a fluorine, oxygen, or nitrogen atom

Cohesion – attraction b/w molecules of same substance Water molecules can have up to 4

H bonds at the same timeCohesion is why drops of water

form beads on smooth surfaces

Hydrogen Bonds Adhesion – attraction b/w molecules

of different substances Water in graduated cylinder dips

at center b/c adhesion b/w glass and water molecules are stronger than cohesion of water molecules

Capillary action – forces draws water out of plant rot up to stems and leaves

Solutions and Suspensions Mixture – material

composed of 2 or more elements or compounds that are physically mixed together but not chemically combined.Ex: vegetable soup,

salt and pepper, Earth’s atmosphere gases

Homogenous MixturesA mixture that has a uniform composition throughout

A solvent is a substance in which another substance is dissolved.

A solute is the substance that is dissolved in the solvent. Food coloring dissolved in

water forms a homogenous mixture.

Heterogeneous Mixtures

In a heterogeneous mixture, the components remain distinct.

A salad is a heterogeneous mixture.

Solutions and Suspensions Conti. 2 types of mixtures made with water are

solution and suspensions.Solution (sol’n) – mixture of 2 or more

substances where the molecules of substance are evenly distributed Ex: table salt put into water

Solute – substance that is dissolved (table salt)

Solvent – substance where the solute dissolves (water)

Solutions and Suspensions Conti.Suspensions – mixture of water and

non-dissolved material Ex: blood is mostly water with many dissolved compounds)

Acids, Bases, pH - P. 164 pH scale – measurement system used to

indicate the concentration of Hydrogen ions (H+) in solution0 7 14

Acids – Substances that release hydrogen ions (H+) when dissolved in water0 6.9 = acidThe lower the number the stronger the

acid

Acids, Bases, pH - P. 164 Bases Substances that release

hydroxide ions (OH–) when dissolved in water 7.1 14 = baseThe higher the number the

stronger the base Buffers –are mixtures that can react

with acids or bases to keep the pH within a particular range.Fluids in human cells is 6.5 -7.5 to

maintain homeostasis.

Section 6.4

The Building Blocks of LifeObjectives•Describe the role of carbon in living organisms.•Summarize the four major families of biological macromolecules.•Compare the functions of each group of biological macromolecules.

Carbon Compounds Organic Chemistry – study of all

compounds that contain bonds between C atoms

Chemistry of Carbon (C)C atoms have 4 valence e-C’s atomic # is 6 (2e- in 1st shell, 4e- in

2nd shell)Each e- can join with e- from another

atom forming strong covalent bondsC can bond with H, O, P, S, N

C has the ability to form millions of different large and complex structures

C

Carbon Compounds Cont. One carbon atom can form four covalent

bonds with other atoms. Carbon compounds can be in the shape

of straight chains, branched chains, and rings.

C

Carbon Compounds Conti.• Macromolecules – giant molecules– Monomers – small unit that can join together with

other small units to form polymers– Polymers – large compound formed from combo of

many monomers– Monomers can be identical like metal links in watch

bands or different beads in multicolored necklace.– 4 groups of organic compounds found in living

things carbohydrates, lipids, nucleic acids, proteins

Carbon Compounds Conti. Carbohydrates (Carbs) –Compounds

composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom; a ratio 1:2:1—(CH2O)nLiving things use carbs as main source

of energyStarches and sugars are carbs used as

an energy sourcePlants and some animals use carbs for structural purposes.

Values of n ranging from three to seven are called simple sugars, or monosaccharides.

Carbon Compounds Conti.• Monosaccharides – single sugar

molecules• Ex: Galactose – in milk and Fructose – in

fruit• Polysaccharides – large macromolecules

formed from monosaccharides • Glucose in blood runs low, glycogen is

released from your liver.• Glycogen – stored in muscles and supplies

energy for muscle movement• Plants use cellulose that gives them

strength and rigidity–Major component of wood and paper

Carbon Compounds Conti. Lipids – macromolecules made from C

and H atoms, including fats, oils, and waxesStore energyImportant parts of biological membranes and

waterproof coveringsSteroids are chemical messengers of lipidsA triglyceride is a fat if it is solid at room

temperature and an oil if it is liquid at room temperature

Lipids that have tail chains with only single bonds between the carbon atoms are called saturated fats.

Lipids that have at least one double bond between carbon atoms in the tail chain are called unsaturated fats.

Fats with more than one double bond in the tail are called polyunsaturated fats.

Carbon Compounds Conti.• Proteins – macromolecules containing

N,C, H, O– Proteins have specific roles• Control rate of reaction and regulate cell

processes• Form bones and muscles• Transport substances into and out of cells

to fight disease

Carbon Compounds Conti.– Proteins are polymers of amino acids• Amino acids – are small compounds that are made of carbon, nitrogen, oxygen, hydrogen, and sometimes sulfur.• 20 amino acids are found in nature & all may be joined together by covalent bonds• Amino acids are monomers of proteins• Amino acids have a central carbon atom.• One of the four carbon bonds is with hydrogen.• The other three bonds are with an amino group (–NH2), a carboxyl group (–COOH), and a variable group (–R).

The number and the order in which the amino acids are joined define the protein’s primary structure.

After an amino acid chain is formed, it folds into a unique three-dimensional shape, which is the protein’s secondary structure, such as a helix or a pleat.

Carbon Compounds Conti. Nucleic Acids – macromolecules

containing H, O, N, C, P Nucleotides – 5-Carbon sugar,

phosphate group, and nitrogenous base

Nucleic Acids store and transmit hereditary or genetic information 2 types – ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)

Nucleic acids are made of smaller repeating subunits called nucleotides, composed of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms.