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