BIO I HONORSRUPP

Chemistry

Matter

Everything in the universe is made of matter

MassMass WeightWeight

Quantity of matter an object has

Mass never changes unless matter is added or taken away from the object

The pull of gravity on mass affects weight

Your weight on Earth or your weight on the Moon

Matter con’t.

Elements

Pure substances that cannot be broken down into simpler substances

More than 90% of living things are made of O, N, C, and H

Two other very important elements are S and P

SPONCH elements

Where are the SPONCH elements?

Atoms

Simplest particle of an element that retains characteristics of that element

Atom structure Nucleus Electrons

Atoms con’t.—Nucleus

Central coreProtonsNeutronsMass of the atom is

carried by the nucleus

Atoms con’t.—Electrons

High energyLittle massMove around the

nucleus in energy levels

Outer electrons have more energy than inner electrons

Each energy level holds certain numbers of electrons

How to read the Periodic Table!

Compounds

Most elements form compounds under normal circumstances

A pure substance made of atoms of two or more elements

Compounds con’t.

WaterPhysical and chemical

properties of atoms and compounds differ O2 is a gas

H2 is a gas

H2O is a liquid

Compounds con’t.

Compounds form depending upon the electrons in the outer energy level

StabilitySome elements do not reactO, N, C, H react readily

Covalent Bonding

Electrons are sharedMolecules are formed

Ionic bonds

Electrons are transferredTable salt example

Sodium loses an electron Chlorine gains an electron

Positive and negative ions attract to form bond

Energy and Matter

Energy is ability to do workForms of energy

Light Heat Chemical Electrical Mechanical

Energy and Matter con’t.

Energy available to do work is called free energy

States of matter Solid—fixed volume

and shape Liquid—conforms to

container and has fixed volume

Gas—fills volume of container and has no fixed volume

Plasma

Energy and Reactions

Reactants ProductsEnergy transfer

Exergonic—release energy—hot reactions

Endergonic—absorb energy—cold reactions

Activation Energy

Energy needed to start a reactionCatalysts—substances that reduce activation

energyEnzymes—catalysts found in living things

ReductionReduction OxidationOxidation

Gains electronsBecomes negatively

chargedThink chlorine in

the ionic bond example

Loses electronsBecomes positively

chargedThink sodium in the

ionic bond example

Redox Reactions

Redox Reactions con’t.

OiLRiG

Solutions

Can be mixtures of solids, liquids, or gases

SoluteSolventConcentratedSaturatedAqueous

Acids and Bases

AcidAcid BaseBase

H+ ionsHydronium ionsSour tasteHighly corrosiveHCl (hydrochloric

acid)Citrus juices

OH- ionsHydroxide ionsBitter tasteVery slippery

because they react with oils

SoapsBleach

Acids and Bases con’t.

pH

A scale that relates numbers of hydronium ions to hydroxide ions

Range from 0 to 14 0 acidic 7 neutral 14 basic

Logarithmic pH 4 has 10x more

hydromium than pH 5 and 100x more than pH 6

Buffers

Chemical substances that neutralize acids or bases

Extremely important to life Enzymes function in very narrow pH ranges Body fluid pH scale (page 42)

Buffer systems maintain the body’s pH at normal and safe levels