Chapter 2 – CHEMISTRYChapter 3, Sect. 3-1

WATER

“…beneath the clothes, we find a man... and beneath the man we find... his... nucleus.”-

Nacho Libre

The structure and function of all living things are governed by the laws of chemistry.

All organisms are made of matter.

Matter is constantly being rearranged through chemical reactions.

BIG IDEAS

Respond to the following in your notebook:

If we continue to break things apart, eventually, will there be nothing left?

Do Now

Living things (organisms):-Made of cells-Grow-Reproduce-Have DNA-Use energy-Need food

Review of Living Things

What do living and non-living have in common?

All things are made up of matter.

Matter-anything that takes up space and has mass (solids, liquids, gas, plasma).

Sect 2-1 Composition of Matter

MASS WEIGHTAmount of matter an object is made of

Pull of gravity on an object

EXAMPLE: On the moon, your mass would be the same!

Your weight would be different…less gravity to pull on your mass.

Earth weight = 150 lbs Moon weight = 25 lbsMass = 56g Mass = 56g

An element is: A pure substance that cannot be broken

down chemically into simpler kinds of matter.

4 Major elements: oxygen, hydrogen, nitrogen, carbon

Elements

Approximately 90% of the mass of living things is made up of these four elements

Elements are arranged according to the number of protons they have.

Each element has unique chemical symbol◦Consists of 1-2 letters◦First letter is always capitalized

Atom-Simplest particle of an element that retains all the properties of that element.

Properties of atoms determine the structure and properties of the matter

they compose.

ATOM

1. Protons 2. Neutrons 3. Electrons

Atoms are made of:

Protons (in nucleus)

Neutrons (in nucleus)

Electrons

Charge Positive (+)

Neutral (no charge)

NEGATIVE (-)

Mass Big Big VERY small

Nucleus-central core of the atom, consisting of protons and neutrons.

Electrons are found moving very fast around the nucleus in orbitals (electron cloud/energy levels).

Atoms with no charge (neutral) have equal protons and electrons.

DRAW A PICTURE OF AN ATOM (LABEL ALL THE PARTS)

Empty Space!!!

Most of an atom is:

Atomic Number - # of protons in an atom (also tells the # of electrons).

Atomic Mass # - number of protons + number of NEUTRONS **LABEL THE DIAGRAM**

A compound is: Atoms of 2 or more elements chemically

joined; the proportion is always fixed. Also known as a molecule (2 or more

atoms chemically joined).

Example: H2O, O2, CO2,

Compounds

1. Share electrons 2. Steal electrons

Covalent Bond Ionic Bond

2 Ways for the elements to combine (BOND):

Salt- the outer electron of Na atom is transferred to the Cl atom ~this results in ions - an atom with a + or – charge.Because + and – attract, this attraction is called an ionic bond.

Atoms, Molecules, Compounds

Atom of Oxygen Molecules of Oxygen Compound containing Oxygen

In your notebook, respond to the following:

On the Periodic Table locate the following elements and give the correct information:Atomic #, Mass, # Neutrons, # ElectronsFluorine NeonHelium

Do Now

Energy It is the flow of energy that the

Biologists seek to understand when they study the chemistry of living

things…

Energy in Living Things:As energy flows through a living organism, it is converted from one form to another.

ENERGY

Atoms and molecules are in constant motion (kinetic energy).Amount of movement determines the state of matter.

States of Matter1.Solid2.Liquid3.Gas

ENERGY

Particles linked together

Has a definite shape Particles vibrate (little

kinetic energy)Example: ice

Solid Liquid Particles not as tightly

linked. Can flow, conform to

the shape of the container.

Definite volume, not definite shape.

Example: water

Particles moving rapidly (lots of energy)Fill volume of any container.No fixed volume or shapeExample: steam (water vapor)

***To cause a substance to change state, thermal energy (heat) must be added to or removed from a substance***

Gas

Watch this video on Chemical Reactions at home!

Chemical Reaction-breaking or forming chemical bonds.

Chemical Equation-represent chemical reactions; reactants are shown on the left, products are shown on the right.

- Na + Cl ---- NaCl Reactants Products

This chemical reaction is breaking

chemical bonds, rearranging and forming

new bonds …

Energy & Chemical Reactions

Chapter 3-1 (pgs 49-51)Biology

Water

The chemical reactions of life , for the most part, occur in water solutions. ..

The chemical reactions of all living things take place in an aqueous environment.

Water’s unique properties make it one of the most important compounds found in living things.

BIG IDEAS

Respond to the following in your notebook:

Which one is more important, food or water?

DO NOW

A water molecule (H2O), is made up of three atoms --- one oxygen and two hydrogen.

H

HO

H

Water

POLAR COMPOUND-a compound where one end is more positively charged while another end is more negatively charged.

In each water molecule, the oxygen atom attracts more than its "fair share" of electrons

The oxygen end “acts” negative The hydrogen end “acts” positive However, Water is neutral (equal

number of e- and p+) --- Zero Net Charge

Water is Polar

Polarity makes water very good at dissolving things (effective solvent).

Water molecules attract other water molecules and solid surfaces.

Why is this important?

http://programs.northlandcollege.edu/biology/Biology1111/animations/dissolve.html

Water forms hydrogen bonds with other water molecules.◦ HYDROGEN BOND-bond between hydrogen of one

molecule and the negative region of another molecule.

◦ Causes water to cling to itself and other surfaces: Cohesion and Adhesion

Hydrogen Bonding

Properties of Water

COHESION-the same kind of particles being attracted to each other (water sticking to other water).◦ Results in surface tension- a surface film on water

that allows insects to walk on the surface.◦ Causes water to be a very stable environment.

Cohesion

Surface Tension…this water strider cannot generate enough force to break through the hydrogen bonds of the water

molecule!

ADHESION-water molecules and molecules of solid surfaces are attracted to each other.◦ EXAMPLE: water sticking to plant leaf

Adhesion

Together, adhesion and cohesion enable water molecules to move through narrow tubes against the force of gravity • Capillarity (capillary action)-the ability of water to

move through fine pores or up a narrow tube against gravity due to adhesion- Example: the flow of water through its stem

Capillarity

A picture of Hydrogen bonds!

Adhesion Also Causes Water to …

Form spheres & hold onto plant

leaves

Attach to a silken spider web

Capillary action (capillarity)

Which gives water the ability to “climb”

structures.

Homeostasis - Ability to maintain a steady state despite changing conditions

Water is important to this process because:a. Makes a good insulatorb. Resists temperature changec. Universal solventd. Coolante. Ice protects against temperature extremes (insulates frozen lakes)

Water & Homeostasis

On a separate sheet of paper, answer the section review questions 1- 6 in your text on page 51.

All answers should be in complete sentences.

Section 3-1 Review

Section 2-3 Solutions

Mixture-substances are combined, but both keep their original chemical properties.

◦Two Types:-Solutions-Suspensions

Mixtures

Solution-a mixture where one or more substances is evenly distributed in another substance.

Aqueous Solution-water is the solvent◦ Made of 2 parts:

1. Solute-substance being dissolved in the solution.

2. Solvent-substance in which the solute is dissolved.

Solutions

Solutions

-Concentration-measure of the amount of solute dissolved in a fixed amount of solution.-More solute = greater concentration

-Saturated solution-no more solute can be dissolved.

Solutions

Substances that don’t dissolve, but separate into tiny pieces.Example: sand in water, dust in a

high wind.- The particles are large

- Blood - red and white blood cells suspended in plasma

- motion of blood keeps the cells from settling out

Suspensions

A mixture with particles larger than a solution, but the particles do not settle out.Can exist as a gel

Example: cytoplasm

Colloids

Solutions are either Acids or Bases

-pH 0-6-Taste sour-Corrosive (burn things, eat away at

materials

*Acid rain can corrode stone and make bodies of water uninhabitable for life.

Example: lemon juice, coke,vinegar, stomach acid.

Acids

-pH 8-14-Bitter taste-Feels slippery-Corrosive*Also called alkaline*

Example: ammonia, milk of magnesia, egg white

Bases

-Measures how acidic or basic a solution is.-From 0-14

Acids Bases

pH Scale

-Neither acidic or basic-pH = 7

Example: water

Neutral Solutions

Weak acids or bases that react with strong acids or bases to prevent sharp, sudden changes in pH (neutralization).

Produced naturally by the body to maintain homeostasis

Buffers