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 food DNA is a molecule Much 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- H 2 O or C 6 H 12 O 6

Structure of Atoms Atoms contain subatomic particles such as: -Protons: positive charge; # determines identity of element -Neutrons: neutral charge -Electrons: negative charge Protons 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