Welcome to the Exciting World of Chemistry!!!!!!!.

Welcome to the Exciting World of Chemistry!!!!!!!

Why study Chemistry in a Biology Class?

Most of Biology is Chemistry in action!If you understand basic chemistry, you will

have a much greater understanding of most of life processes!The Digestive system is a series of chemical

reactions that break down foodDNA is a moleculeMuch much more!!

Chemistry of Life

Elements: substance that cannot be broken down into simpler substances. Ex- O, H, N

Atoms: smallest unit of an element that still has all properties of that element.

Molecule: chemical structure composed of 1 or more atoms. Ex- H2O or C6H12O6

Structure of Atoms

Atoms contain subatomic particles such as:-Protons: positive charge; # determines identity of element-Neutrons: neutral charge-Electrons: negative chargeProtons and Neutrons are in center of atom.Electrons surround center in an electron cloud.

Atoms

Molecules

Chemical Reactions

Involves making and breaking bonds.

Cells are basic unit of life like atoms are basic unit of matter.

Chemical reactions are important to cells:

1. Only way to form new molecules for growth and maintenance.

2. Allows energy to be stored, used or released.

Chemical Bonds

Ion- positively or negatively charged atom from gaining or losing electrons.

Covalent Bond: Forms when 2 atoms share 1 or more pairs of electrons. Ex- water

Ionic Bond: Attraction between oppositely charged ions. Ex- sodium chloride (salt)

Ionic Bond

Covalent Bond

Acids and Bases

Acids have more H+ ions than OH-

Bases have more OH- ions than H+ ions.

Acids: Taste sour, do not feel slippery

Bases: Taste bitter, feel slippery (cleaning solutions)

BOTH ACIDS AND BASES CAN BE DANGEROUS!!!!!!!

The pH Scale

Acid=pH 1-6

Base=pH 8-14

The pH Scale

Neutral substances like water have a pH of 7.

pH of 1 is highly acidic and pH of 14 is highly basic.

pH scale is a logarithmic scale; based on a power of 10. pH of 4 is 100x stronger than pH6