Terminology Element – A pure substance that consist entirely of one type of atom – Ex. Gold (Au) Isotope – Atoms of the same element that differ in the number of neutrons they contain – Ex. Carbon-12 and Carbon-14 Compound – A substance formed by the chemical combination of two or more elements – Ex. Salt (NaCl) Molecule – Two or more atoms held together by covalent bonds – Ex. Water (H2O)
Atomic Bonding Ion – Any atom with a charge due to the loss or gain of electrons – Ex. Hyrdoxide (OH - ) Ionic Bond – a bond characterized by the TRANSFER of electrons from one atom to another Covalent Bond – a bond characterized by the SHARING of electrons between two atoms
van der Walls Forces Slight attraction that develops between oppositely charged regions of nearby molecules
Skill Check What is the biggest difference between an electron and a proton or neutron, other than charge or location? Where are protons and neutrons located in an atom? What is another name for the outermost electron shell? What is the difference between an ionic bond and a covalent bond? Why can geckos scale walls like Spider-Man?
Universal Solvent – because water is a polar molecule (Solution, solute, solvent) Cohesion – because of hydrogen bonding (water molecules like to stick together) Adhesion – Water likes to stick to other things (meniscus) Surface Tension – Top layer of molecules is more attracted to itself than air High Heat Capacity – Temperature stabalizer, not a good conductor
Acids, Bases and pH Acid – compound that releases a proton (H+) when it dissolves in water Base – compound that takes up a proton (H+) when it dissolves in water pH – a universal scale measuring the H+ concentration of solutions
Skills Check What is an element? What is the difference between a molecule and a compound? What is a covalent bond? What is are the outermost electrons called? What is the Octet Rule?
Intro to Organic Chemistry Organic Chemistry is a branch of science dedicated solely to the study of the carbon atom. Carbon atoms have 4 valence electrons. Carbon can form millions of different molecules, in a variety of shapes.
Intro to Macromolecules Macromolecules are giant molecules made from hundreds or thousands of smaller molecules. The smaller molecules are referred to as monomers. Monomers join together to make polymers. The process by which monomers join to make polymers is called polymerization.
Macromolecule Groups Carbohydrates Lipids Nucleic Acids Proteins
Group Time Please split up into 4 groups. You will be handed a worksheet pertaining to one of the four groups of macromolecules. Using your book, take a few minutes to finish the worksheet as a group. Nominate one or two presenters to come up to the board and teach the rest of the class what you have learned about your macromolecule.
Chapter 2.4 & 2.5 Chemical Reactions and Enzymes
Chemical Reactions Chemical Reaction – Process that changes one set of chemicals (the reactants) into another set of chemicals (the products) – Ex. 2H + O H 2 0 Oxidation reactions are slow, other reactions are faster (think explosions) All chemical reactions involve the breaking and forming of bonds
How do Chemical Reactions Start? Some are spontaneous – Spontaneous reactions release energy
How do Chemical Reactions Start? Some are not – These reactions require the input of energy to begin (referred to as Activation Energy)
Where Can We Get Some Activation Energy? From Catalysts, of course! Any substance that speeds up a reaction is called a Catalyst. Examples of catalysts:
Enzymes Enzymes are proteins that act as catalysts inside the body. Enzymes are specialized to work best at a certain pH and a certain temperature. Every enzyme has an “active site” where substrates can attach or bind