Matter, Energy, and Life
Matter: Forms, Structure, and Quality
■ Element:
building blocks of matter
■ Compound:
two or more elementscombined
■ Atom:
smallest units of matter
■ Ion:
charged atom
■ Molecule:
two or more atoms combined
What’s in an Atom?
Protons
+ positive charge
Neutrons
no charge
Electrons
- negative charge
Atomic Number
number of protons
Fig. 3-4 p. 48
Examples of Atoms
Chemical Bonds
Covalent –
“sharing”
Chemical Bonds
Ionic -
“transferofelectrons”
Lipids – fats and oils; horomones
Nucleic Acids – geneticinformation
Carbohydrates – glucose, sucrose,
fructose, galactose
Proteins – amino acids with
carbon backbones; enzymes
Organic Compounds
Solid
Liquid
Gas
Plasma
The Four States of Matter
Which State of Matter is the MostAbundant?
Plasma Plasma
- sun and stars
- high energy mix of + and –particles
- formed when electrons are takenfrom the nuclei of atoms (highenergy process)
Why is There No “Away”?
Law of Conservation of Matter
We cannot destroy atoms.
We can only rearrange theminto different spatialpatterns (physical) orinto differentcombinations(chemical).
Everything we think we have“thrown away” is still here in oneform or another.
Example
DDT
- banned, but still residues in importedcoffee, tea, fruit, and other foods.
- or as fallout from air masses moved longdistances by wind.
Law of Conservation of Matter
- means we will always face the problemof what to do with wastes and pollutants.
Pollution
3 Factors that Determine the Severity of a Pollutant’sChemical Effects:
1. Chemical Nature
2. Concentration
- parts per million (ppm)
3. Persistence
- measure of how long the pollutant stays in the air, water, soil, or body.
Classification of Pollutants:
1.Degradable (reduced to acceptable levels)
2.Slowly Degradable (decades or longer-DDT)
3.Nondegradable (natural processes cannot break down -lead,arsenic)
Energy
Energy - Ability to do work!!
Work – application of force over distance (joules)
Power – rate of energy flow of the rate of work done;watt = 1 joule/sec
100 watt light bulb for 10 hours = 1,000 watt-hours or1kWh)
Forms of Energy
Kinetic
- energy in motion
Examples: Wind, Flowing Streams,Electricity
Potential
- stored energy
Examples: Unlit Stick of Dynamite,Rock in Hand
Forms of Energy
The five main forms ofenergy are:
Heat
Chemical
Electromagnetic
Nuclear
Mechanical
Laws of Thermodynamics
FIRST LAW OF THERMODYNAMICS
In all physical and chemical changes, energy isneither created nor destroyed, but it may beconverted from one form to another.
Energy input always equal energy output.
You cannot get something for nothing in terms ofenergy quantity.
SECOND LAW OF THERMODYNAMICS
When energy is changed from one form to another,some of the useful energy is always degraded tolower quality, more dispersed, less useful energy,usually heat.
Energy Conversions
In an automobile engine,fuel is burned to convertchemical energy into heatenergy. The heat energy isthen changed intomechanical energy.
Chemical HeatMechanical
Convection
Conduction
Radiation
Heat from a stove burnercauses atoms or molecules inthe pan’s bottom to vibratefaster. The vibrating atoms ormolecules then collide withnearby molecules, causingthem to vibrate faster.Eventually, molecules oratoms in the pan’s handle arevibrating so fast it becomestoo hot to touch.
As the water boils, heat fromthe hot stove burner and panradiates into the surroundingair, even though air conductsvery little heat.
Heating in the bottom of a pan
causes the water to vaporize
into bubbles. Because theyare lighter than thesurrounding water, they rise.Water then sinks from the
top to replace the risingbubbles. This up and downmovement (convection)eventually heats all of thewater.
Transfer of Heat Energy
Energy
Energy Quality
- Energy source’s ability to do usefulwork.
High Quality Energy
1. Concentrated
2. Provides useful work
Examples: Electricity, ConcentratedSunlight
Energy Continued
Low Quality Energy
1. Dispersed
2. Little useful work
Example: Heat dispersed in theAtlantic Ocean.
Nuclear Changes
Matter undergoes a nuclear change:
1. natural radioactive decay
2. nuclear fission
3. nuclear fusion
Natural Radioactive Decay
A nuclear change in which unstableisotopes spontaneously emit fast-moving particles (matter), high-energyradiation, or both at a fixed rate.
Unstable Isotopes are called “radioactiveisotopes” - radioactive decay continuesuntil isotope becomes stable.
Isotopes have a different number ofneutrons but the same number ofprotons.
Natural Radioactive DecayContinued
Radiation emitted by radioisotopes isdamaging ionizing radiation.
Gamma Rays – a form of high-energyelectromagnetic radiation emitted fromradioisotopes. You do not want to beexposed to these waves.
Alpha/Beta Particles – high-speedionizing particles emitted from thenuclei of radioisotopes.
What is Half-Life?
The amount of time needed for one-half ofthe nuclei in a given quantity of aradioisotope to decay and emit theirradiation to form a different isotope.
Decay continues, often producing a series ofdifferent radioisotopes, until a stable,nonradioactive isotope is formed.
The half-life estimates how long a sample ofradioactive isotope must be stored in asafe container before it decays to a safelevel and can be released into theenvironment.
Half-Life Continued
A general rule is that such decay to a safe leveltakes about 10 half-lives.
Example: Plutonium-239 has a half-life 24,000years. It is produced in nuclear reactors andused in nuclear weapon production. It mustbe stored safely for 240,000 years (10 x24,000).
Plutonium-239 can cause lung cancer when itsparticles are inhaled in minute amounts.
Ionizing radiation exposure from alpha particles,beta particles, and gamma rays can damagecells by genetic damage (mutations of DNA)or somatic damage (tissue damage).
Nuclear Fission
Neutrons can split apart the nuclei of certainisotopes with large mass numbers andrelease a large amount of energy.
1. Neutron hits the nucleus of an isotope.
2. Nucleus splits and releases 2 or 3 moreneutrons and ENERGY.
3. Each of these neutrons can go on to causeadditional fission.
Multiple fissions create a chain reaction whichreleases an ENORMOUS AMOUNT OFENERGY.
Examples of Nuclear Fission
Atomic Bomb – An enormous amount ofenergy is released in a fraction of a secondin an uncontrolled nuclear fission chainreaction.
Nuclear Power Plant – The rate at which thenuclear fission chain reaction takes placeis controlled. In conventional nuclearfission reactors, the splitting of uranium-235 nuclei releases energy in form of heat,which produces high-pressure steam tospin turbines and thus generateelectricity.
Nuclear Fusion
Nuclear fusion is a nuclear change in whichextremely high temperatures force the nucleiof isotopes of some lightweight atoms to fusetogether and form a heavier nucleus which inturn releases large amounts of energy.
Extremely high temperatures (at least 100 million oC) are needed to force the positivelycharged nuclei (protons strongly repel oneanother) to fuse.
Source of energy in sun and stars.
Sun-hydrogen isotopes fuse to make helium-energy and heat.
What are Nuclear Reactionsused for?
Energy Production: nuclear powerplants generate electricity for ourhomes.
Medical Technology: cancer treatment,X-rays.
Nuclear Weapons: atomic bomb,hydrogen bomb.
Nuclear Power Plant
Atomic Bomb
