1. Chapter 2 Chemistry

2. Unit 4 Lecture 1 Topic: Introduction to Chemistry
Covers Chapter 2 (pg 30 – 32)

3. Recap: Living vs. Nonliving
Differences
Living Organisms:
Made up of at least one cell * Has a metabolism
Has DNA  * Maintains homeostasis
Needs a food source  * Responds to stimuli
Grows * Reproduce
Similarities:
All things (living and nonliving) are made up of MATTER
MATTER - anything that takes up space and has mass
MASS - how much matter an object has

4. Atoms Matter is made up of chemical elements, or ATOMS
ATOM - basic building block of matter
Smallest, stable unit of matter
An element is a specific type of atom
Elements/atoms cannot be broken down into a simpler  stable type of matter
All known elements are arranged into a table
PERIODIC TABLE OF ELEMENTS
Over 100 known elements on Periodic Table, but only around 30 are  important to living organisms
4 Major elements in living organisms:
~ Oxygen  ~Hydrogen ~ Carbon  ~Nitrogen
Atoms make up everything on Earth!

7. Atoms Atoms (elements) are made up of three basic parts:
1. PROTONS  NEUTRONS  ELECTRONS
Protons
Neutrons
Electrons
Charge
Positive
Neutral
Negative
Mass
Large
Very Small

8. Atoms Atomic Mass = Number of Protons + Number of Neutrons
Atomic charge = Number of Protons + Number of electrons
Neutral atoms (atom without a + or – charge) have the same number of electrons as protons
Protons and Neutrons are located in the center of the atom, known as the NUCLEUS
Electrons circle around the nucleus in orbitals
1st level can hold 2 electrons 2nd level can hold 8 electrons
Element stable when outer orbital (energy level) is full
The only elements that have a full outer orbital are found in the last column of the periodic table
These elements are known as inert gas or noble gas
Orbitals are known as energy levels

9. End of Lecture 1

10. Unit 4 Lecture 2
Topic: Types of Bonds
Covers Chapter 2 (pg 33 – 34)

11. Types of Bonds Most elements are not stable as an individual atom
Elements that are unstable (do not have a full outer orbital) will CHEMICALLY combine with other elements to form a molecule.
When elements chemically combine, it is called a bond

12. Types of Bonds Types of Bonds:
Covalent Bond – two atoms sharing electrons
Very strong in a watery solution
Example: Carbon dioxide, Oxygen Gas, Water

13. Types of Bonds Types of Bonds:
Ionic Bond – bond between a positively charged ion and a negatively charged ion (opposites attract)
Ion – an atom with a positive or negative charge
Ionic bond easy to break in a watery solution
When the ionic bond breaks, will go back to a positively charged ion and a negatively charged ion

15. Types of Bonds Hydrogen Bond
Type of ionic bond that forms between two different water molecules
Very weak, broken easily
But, Hydrogen bonds are very important to living organisms
Causes Cohesion and Adhesion to occur

16. Types of Bonds Hydrogen Bond
Cohesion – attractive forces between water molecules
EXAMPLE: Surface Tension, Rain Drops
Adhesion – attractive forces between water molecules and another compound/surface
Allows water to move up through narrow tubes against gravity (clings to sides of tubes)
EXAMPLE: Helps plants transport water from roots to leaves

17. End of Lecture 2

18. Unit 4 Lecture 3 Topic: Water, pH, Chemical Reactions
Covers Chapter 2 (pg 35 – 42)

19. Solutions Solution – mixture of 2 or more substances
Solute – substance dissolved
Solvent – the material dissolving the solute
Aqueous Solution – solution in which water is the solvent
Concentration – measurement of the amount of solute dissolved in the solvent

20. Solutions – Water Water (H2O) is the universal solvent
Water is formed by covalent bonds between Hydrogen and Oxygen
Polar Molecule – electrons not shared evenly, resulting in a molecule with one side having a negative charge & the other side having a positive charge
The negative charge and positive charge cancel each other out, so the molecule (as a whole) is considered neutral (no charge)
In water, Oxygen has a stronger pull on the electrons
This makes Oxygen slightly negative and the Hydrogens slightly positive  

21. pH Scale
Measuring the concentration of Hydronium Ions (H+) and Hydroxide Ions (OH-)
Scale from 0 – 14

22. pH Scale Neutral solution pH = 7; OH = H
Example: water (7), cells ( )
Acid
pH < 7; OH– < H+
More H+ (hydronium) ions than OH– (hydroxide) ions
Sour taste, Highly corrosive
Example: vinegar (3), stomach acid (2), acid rain (<5.6)
Base (aka "Alkaline”)
pH > 7; OH– > H+
More OH– (hydroxide) ions than H+ (hydronium) ions
Bitter taste, Slippery feel, Soap
Exs: Milk of Magnesia (10.5), Ammonia (11.5), Soap

23. pH Scale Units on the pH scale are logarithmic
Increase or decrease by factors of 10
Example: pH 3 is not two times more acidic than a pH 6, but 1,000 times more acidic!
Buffers
Neutralize small amounts of an acid or base
Buffering systems help keep our body’s fluids stay at a normal and safe pH level

24. Energy Energy – ability to do work or cause change
Comes in many forms, and can change forms
Some types of energy:
Potential, Kinetic, Chemical, Thermal, Solar, Nuclear
Free Energy – energy in a system that is available  for work (to fuel cell processes)
Activation Energy – energy required to start a chemical reaction
Catalyst – chemical that reduces amount of activation energy
Enzymes are a main type of catalyst

25. Activation Energy

26. Energy Na + Cl  NaCl Reactants  Product(s)
Arrow always points to products
Exergonic Reaction – releases free energy
Endergonic Reaction – absorbs free energy

27. Energy Life processes require a constant supply of energy
Most common type of cell energy is ATP (Adenosine Triphosphate)
Made up of a 5-carbon sugar, adenine molecule, and a chain of THREE phosphate groups
The phosphate molecules are held together by covalent bonds
When the last phosphate's bond is broken, a lot of energy is released. The energy is used to fuel cell reactions
Forms ADP (Adenosine Diphosphate)

28. End of Lecture 3