CHEMISTRY

Composition of Matter

Energy

Solutions

Composition of Matter

Why discuss chemistry in biology class?The structure and function of all living things

are governed by the laws of chemistry

Matter

Makes up everything in the universe Anything that occupies space and has

massMass is not = to weight

○ Weight is the pull of gravity on an object (mass would not change because it is the “quantity of matter” an object has…

○ You would still be the same “being” on Earth and on the moon = your mass doesn’t change…HOWEVER…your weight would be significantly less on the moon due to the pull of gravity

Chemical changes in matter

Essential to all life processes Living things are made up of the same

kinds of matter that make up nonliving things

Understanding changes in matter = understanding of life processes of organisms

Elements

Pure substances that cannot be broken down chemically into simpler kinds of matter90% of mass of all kinds of living things is

composed of combinations of 4 elements:○ Oxygen (O)○ Carbon (C) ○ Hydrogen (H)○ Nitrogen (N)

Chemical Symbols

Atomic Number

Chemical Symbol

Atomic Mass

Name

Atoms Simplest particle of an element

that retains all of the properties of that elementNucleus = core of atom

○ Made of protons (+) and Neutrons (no charge)All atoms of a given element have same

# of protonsAtomic # = number of protons

Electrons ○ High energy particles; negatively

charged; move about nucleus at very high speeds in “energy levels”

○ First e- level = up to 2 e-○ Second e- level = up to 8 e-

AtomicEnergyLevels

Compounds

Under natural conditions, most elements do not exist by themselves

A compound is a pure substance that is made up of atoms of two or more elements that are fixed = water: H2O = chemical formula indicates that the atoms always combine in a proportion of two Hydrogen atoms to one Oxygen atom

Making Compounds

Stable atom = outermost energy level is filled

Most atoms are not stable in natural state = meaning they tend to react/combine with other atoms in order to achieve stability

Undergo chemical rxns to achieve stability = chemical bonds are broken; atoms are rearranged; new bonds are made

Bonds

Covalent = 2 atoms share one or more pairs of e-

Ionic= one e- gets transferred from one atom to another, resulting in more stability and giving both atoms a charge of + or -

You payin’ attention????

What are you to do now? You are going to complete a “Guided

Notes” (GN) activity…

On page 35 of your textbook, you will notice that there are 4 objectives listed. Make a chart/table using the objectives and take notes from the reading.

Ex: Objective Notes

List the three states of matter, and explain how matter can change state

• Your notes will go here• You can bullet• Leave space so that

you can take notes in class!

Back to our notes!!!!!

Energy - E

Energy is the ability to do work Biological systems need/use: chemical

energy, thermal energy, electrical energy, and mechanical energy

Free energy = energy available for work (cell processes would benefit from this)

Do Right this Very Minute (DRTVM) Two Truths and a Lie….

Take an index card from the front deskFrom the homework (a few nights ago), write

down two truths and a lie about “Energy” You have 2 minutes!When 2 minutes are up…you are to find 3 people

NOT at your table and try to trick them…Write down all 3 names on the other side of your

card and write down if they picked the lie or not…You have 5 minutes!

States of Matter Solid, liquid, or gas

Atoms in constant motion…their speed determines the state…Solid = particles are tightly linked in

definite shape (fixed volume and shape)

Liquid = particles are not as tightly linked (fixed volume)

Gas = particles move most rapidly; move freely; little or no attraction to each other

*Thermal energy must be added to change a state

Energy and Chemical RXNs

Chemical Rxns

Our bodies need a lot of energy…we get it from breaking down sugars from food into CO2 and H2O

Exergonic = chem. rxn where E is released

Endergonic = chem. rxn where E is absorbed

Activation E

What gets you up and moving faster???

Really…activation E the amt of E needed to start a rxn

Catalysts lower the amt of activation E necessary for rxn

Enzymes are important catalysts to living things – specific to individual chemical rxns

E movement

Constant flow of energy into and throughout living things

Many involve transfer of e- between atoms

Redox Reactions – These work together

When a compound becomes “oxidized”it loses its electrons to another compound…

When a compound gains electrons, it becomes negativelycharged, or reduced.

Solutions (solns) Solution (soln) – 1+ substances are =

distributed in another substance Solute – dissolved substance Solvent – does the dissolving (water is the

universal solvent) Concentration – measurement of amt of

solute dissolved in a fixed amt of soln Saturated soln – no more solute can

dissolve Aqueous soln – water is solvent

Dissociation of H2O

Breaking apart of water

Acids and Bases

When an acid is introduced into a neutral solution, it adds H+ ions

When a base is introduced into a neutral solution, it adds OH- ions

pH Scale developed to

compare the relative concentration of hydronium ions and hydroxide ions in a solution

Ranges from 0 to 14 0 = very acidic 14 = very basic 7 = neutral (water)

See Figure 2-10 on page 42

BuffersDefinitely NOT this guy!

Chemical substances that neutralize small amts of either an acid or a base added to a soln