1/23/12-Do-Now:• Take out Your Cell Wordsearches from Friday

& Set out your Vocabulary from Week 2 to be checked.

• Copy AND answer the following questions on a blank sheet of paper.

1.How do you think you did on the Cell test?2.Honestly, how long did you study?3.Have you come in for help?4.What could YOU do to improve your grade?5.What could I do to help you?

Chemistry

Matter & Mass

• MATTER is anything that occupies space and has mass.

• MASS is the quantity of matter an object has.

ELEMENTS• Pure substances

that cannot be broken down chemically into simpler kinds of matter

• There are over 100 elements, though fewer than 30 are important to living things.

ATOMS• Simplest particle

of an element that retains all of the properties of that element

• So small true structure can’t be observed

• Models help us to understand atoms

The Nucleus of an Atom

• Central core of an atom composed of:– PROTONS-

positive (+) electrical charge

– NEUTRONS-neutral (no) electrical charge

ATOMIC NUMBER

• Number of protons in an atom• Atomic number generally appears

above the chemical symbol

ELECTRONS-negatively (-) charged particles that balance out the protons, orbit around the nucleus of the atom, found in different energy levels

COMPOUND

• Pure substance made up of atoms or 2 or more elements

• Elements are typically not found “alone” in nature. They undergo CHEMICAL REACTIONS to become stable. BONDS (attachments) are formed.

COVALENT BONDS• When 2 atoms

share one or more pairs of electrons

• Water is made of 2 hydrogen atoms and 1 oxygen atom.

• A MOLECULE is the simplest part of a substance that retains all of the properties of the substance & can exist in a free state.

IONS & IONIC BONDS• An atom or

molecule with an electrical charge

• The “Sodium Ion” is written Na+.

• “Chloride” is written Cl-.

• The positive and negative charges of the Na+ & Cl- are attracted to each other, creating an IONIC BOND.

ENERGY

• The ability to do work or cause change

• Can be converted to different forms

• FREE ENERGY-energy in a system available to do work– In a cell, it is the energy available to

fuel cell processes.

States of Matter

• SOLIDS• LIQUIDS• GASES

CO2 + H2O H2CO3

• REACTANTS– Usually shown

on left side of chemical equations

– What is needed to begin the reaction

• PRODUCTS– Usually shown

on the right side of chemical equations

– What is found when the reaction is completed

Energy Transfer

• EXERGONIC REACTIONS– Involve a net

release of free energy

• ENDERGONIC REACTIONS– Involve a net

absorption of free energy

ACTIVATION ENERGY• Amount of energy needed to start

a reaction• CATALYSTS-reduce the amount of

activation energy needed for a reaction– ENZYMES-important group of

catalysts in living things

Describing Solutions

• SOLUTION-mixture where 1 or more substances are evenly distributed in another substance

• SOLUTE-the substance dissolved in the solution

• SOLVENT-the substance the solute is dissolved in

• CONCENTRATION-measurement of the amount of solute dissolved in a fixed amount of the solution

Think about it…

• Imagine you are making sugar free grape kool-aid. Identify the solution, solute, and solvent.

?????

Think about it…

• Grape kool-aid (final product)=solution

• Kool-aid mix (before adding water)=solute

• Water=solvent

**Water is the “universal solvent.”**

pH Scale

• ACIDS– Solution with more

hydronium ions than hydroxide ions

– Sour taste– Highly corrosive– pH of 1-6 is acidic

(1 being the strongest acid)

• BASES– Solution with more

hydroxide ions than hydronium ions

– “ALKALINE” refers to bases

– Bitter taste– Feel slippery– pH of 8-14 is basic

(14 being the strongest base)

pH in Your Body

Buffers

• Neutralize small amounts of acids or bases added to a solution

• Complex buffering systems maintain the pH values of your body’s main fluids at normal and safe levels.