MATTER AND ENERGY

CHAPTER TWO

Concepts

• Matter consists of elements and compounds, which in turn are made up of atoms, ions, or molecules

• Whenever matter undergoes a physical or chemical change, no atoms are created or destroyed (the law of conservation of matter)

What is matter?

• Three physical states:– Solid– Liquid– Gas

• Two chemical forms of matter:– Elements– Compounds

STATES OF MATTER

Other facts about matter:

• The smallest unit of matter is ___?

• What is an ion?• What is a molecule

and how are they held together?

• What are subscripts and what do they represent?

• The three physical states of matter on earth are____.

Building Blocks of Matter

• Atoms (most basic)

• Molecules

• Ions

What is an element?

• A fundamental type of matter that has a unique set of properties and cannot be broken down into simpler substances by chemical means

• Periodic table: elements arranged based on their chemical behavior

Some important elements

• Composition of the earth’s crust

• Inorganic compounds• All compounds that do

not contain carbon• Crust - outermost

layer of earth - mainly inorganic minerals and rocks

Atomic Theory

• All elements are made of atoms

• Most widely accepted scientific theory in chemistry

The Atom

• Major parts of the atom are:– Protons

– Neutrons

– Electrons

• The protons and neutrons form the ___

• Electrons are located in ____

• What is the atomic number?

• What is the mass number?

• What are isotopes?• How do you identify

isotopes in the symbol?

ISOTOPES

Molecule

• A second building block of matter

• Combination of two or more atoms of the same or different elements held together by chemical bonds

• Basic building blocks of any compound

WHAT ARE IONS?

• IF AN ATOM HAS 11 PROTONS AND 10 ELECTRONS IT IS A ______ION.

• IF IT HAS 17 PROTONS AND 18 ELECTRONS IT IS A ___ ION.

• HOW ARE THE CHARGES ON AN ION SHOWN AFTER THE SYMBOL?

Holding atoms together

• What does a chemical formula tell you?

• What are the characteristics of ionic bonds?

• What is an example of an ionic bond?

• What are covalent bonds?

• What is an example of a covalent bond?

• What are hydrogen bonds?

• What is an example of a hydrogen bond compound?

Covalent bonds

Other important compounds

Hydrogen bonds

What are organic compounds?

• What element do all organic compounds contain? What other elements can be also combined?

• Organic compounds can be natural or synthetic.

• Most organic compounds are covalent bonds.

P 38

• Organic Molecules– Monomers– Polymers

Types of organic compounds:

• Hydrocarbons made up of ___

• Chlorinated hydrocarbons– An example would be:

• Chlorofluorocarbons -– An example would be:

• Simple carbohydrates

• Monomers• Polymers• Complex

carbohydrates• Proteins• Nucleic acids

MORE ON PROTEINS:

• ALPHA-AMINO ACIDS - 20 DIFFERENT MONOMERS - # & SEQUENCE SPECIFIED BY GENETIC CODE IN DNA MOLECULES IN CELLS

• NUCLEIC ACIDS - DNA & RNA - MADE BY LINKING MONOMERS CALLED NUCLEOTIDES TOGETHER

• GENES - SEUQENCES OF NUCLEOTIDES - CARRIES A CODE WHICH CONTAINS TRAITS PASSED FROM PARENTS TO OFFSPRING

• GENOME - ALL OF THE GENETIC INFORMATION FOR AN ORGANISM.

• What are GENE MUTATIONS?

• What are CHROMOSOMES?

Matter quality

• A measure of how useful a matter resource is - based on availability and concentration

• High quality matter -organized, concentrated and usually found near earth’s surface

• Low quality - disorganized, dilute,often deep underground or dispersed in the ocean or atmosphere - have little potential use as a matter resource.

Matter Quality

WHAT IS ENERGY?

• What is ENERGY ?

• What is WORK?

• What is a FORCE?

• Forms of energy - light, heat, electricity, chemical energy, mechanical energy, and nuclear energy

Types of energy

• What is Kinetic energy? • What does it depend

on?• Examples: wind,

flowing water, electricity, electromagnetic radiation, heat, temperature

• What is Potential energy?

• What does it depend on?

• Potential energy changes into kinetic energy etc.

Energy

• Kinetic– Heat

– Electromagnetic Radiation

• Potential

• Renewable• Nonrenewable

Kinetic Energy

• Heat (thermal energy)– Total kinetic energy of all moving atoms, ions,

or molecules in an object, a body of water, or the atmosphere

– Faster moving particles = warmer

Temperature vs Heat

• What is temperature?– The average speed of the

motion of the molecules in a given sample of matter

• What is heat?– The total kinetic energy of

all the moving molecules within a given substance

How is heat transferred?

• What is convection?

• What is Conduction?

• What is Radiation?

Kinetic Energy

• Electromagnetic radiation– Energy travels in the form of a wave as a result

of changes in electrical and magnetic fields– Each form of electromagnetic radiation has a

• Wavelength

• Energy content

• Short wavelengths = more energy (gamma rays)

Electromagnetic spectrum

• Ionizing radiation - harmful forms of electromagnetic radiation

• Non-ionizing radiation - does not contain enough energy to form ions

• Ionizing Radiation – from natural or background sources– Can come from space, soil, food, etc.– Has energy to knock electrons from atoms

• Can disrupt living cells, interfere with body processes and cause cancer.

– Nonionizing radiation doesn not contain enough energy to form ions.

Energy quality

• An energy source’s ability to do useful work

• High-quality - organized or concentrated - can perform useful work– Electricity, coal, gasoline, sunlight,uranium

• Low - quality - disorganized or dispersed- can perform little useful work– Heat in water, air, etc.

Changes in Matter

• Physical

• Chemical

• Nuclear

Changes in matter

• What is a Physical change?

• What are some examples of physical changes?

• All changes involve energy - taken in or released

• What is a Chemical change ?

• What is an example?• What is a CHEMICAL

Equation?• Reactants --> products

Law of Conservation of Matter

• All the matter on earth is here and cannot be “thrown away” - there is no “away”

• Earth is a closed system

• Matter cannot be created nor destroyed

• Matter is not consumed

Law of Conservation of matter and energy

• Applies to nuclear changes because a certain amount of mass (matter) is changed into energy.

• The TOTAL amount of matter and energy involved remains the same

Nuclear Changes

• Natural radioactivity- when nuclei of certain isotopes spontaneously break down into one or more different isotopes

• Three types:– Natural radioactive decay

– Nuclear fission

– Nuclear fusion

Natural radioactive decay

Unstable isotopes - radioisotopes - spontaneously break down and emit:

• Alpha particles - positively charged helium nuclei

• Beta particles - high speed electrons

• Gamma rays - high speed ionizing electromagnetic radiation

Half-life

• Rate of decay

• Time needed for one half of the nuclei in a radioisotope to decay and emit their radiation

• Eventually forms a new element

• Is not affected by temp. pressure, chemical changes, etc.

• Rule is store for 10 half-lives for safety

Nuclear fission

• Nuclei of atoms with large mass numbers are split into lighter nuclei

• Neutrons used to split• Releases more

neutrons and energy• Critical mass - needed

to start reaction

More on fission

• Atomic bombs - uncontrolled nuclear fission

• Damage cells• Used in nuclear power

plants

Nuclear fusion

• Two isotopes of light elements are combined under great heat and pressure to form a heavier nucleus

• Harder to initiate• Thermonuclear

weapons

Net Energy• Only Energy that really counts

• Energy Quality – we want to use resources that produce the most net energy and expend very little energy

• P 375

• Net energy yield: the usable amount of high-quality energy available from an energy resource

What is energy efficiency?

• A measure of how much useful work is accomplished by a particular input of energy into a system

• Always measured as a percent (%)

• Affects life because you get and use high quality matter and energy , use it and add low quality heat and waste back into the environment.

Energy Inefficiency• Costs $570,000 per minute (US)• Due to:

– Data Centers (electronic clouds) – use only 10% of the electric energy they pull from the grid – other 90% ends up as low-quality heat that flows into the environment

– Internal combustion engine – motor vehicles (wastes 80% of the energy in the fuel)

– Nuclear power plants – produce electricity but waste about 75% of the energy in the nuclear fuel

– Coal-fired power plants – wastes about 65% of the energy that is released by burning coal

Nuclear Power Plants

• Thermal power station in which the heat source is a nuclear reactor

• Heat is used the generate steam, which drives a steam turbine connected to an electric generator

• This produces electricity

• 435 nuclear power plants

Light Water Reactors

• Pressurized water reactors

• Boiling water reactors

How Reactors Work• Light-water reactors (LWRs)

LWRs• Core

– fuel rods – packed with pellets = 1 ton of coal • Provide fuel for nuclear reactors

– control rods - absorb neutrons and slow reaction down

– water - keeps core cool(coolant), slows down the neutrons so that they are at the right speed to trigger the next reaction (moderator) and produces steam to make electricity

• high pressure steam from reactor is used to heat water which then produces steam used to run a turbine

Pressurized Water Reactor

• Constitutes the large majority of all Western nuclear power plants

• Light water reactor• The primary coolant (water) is pumped under high

pressure to the reactor core where it is heated by the energy generated by the fission of atoms

• The water then flows to a steam generator where it transfers its thermal energy to a secondary system where steam is generated and flows to turbines

Pressurized Water Reactor

• Animation

• http://commons.wikimedia.org/w/index.php?title=File%3APWR_nuclear_power_plant_animation.ogv

Boiling water reactors

• Light water nuclear reactor used to generate electrical power

• Main difference from PWR: the reactor core in the PWR does not boil the water

• Developed by Idaho National Laboratory and General Electric in the mid-1950s

Boiling water reactors

Turbine

• Greek: “Turbulence”

• A rotary mechanical device that extracts energy from a fluid flow and converts it into useful work

• Purpose of steam turbine: convert the heat contained in steam into mechanical energy

TVABrowns Ferry Nuclear Plant

Early examples of turbines

• Windmills

• Waterwheels

Wind Farm

• P 402 - Jigsaw

First law of thermodynamics

• In all physical and chemical changes, energy is neither created nor destroyed but it may be converted from one form to another

• Energy input always equals energy output

• You can’t get something for nothing - cannot get more energy out of a system than is put in!!!

Second law of thermodynamics

• When energy is changed from one form to another, some useful energy is always degraded to lower quality less useful energy usually heat lost to the environment

• We ALWAYS end up with less useful energy than we started with.

• An incandescent light bulb - 5 % light, 95% heat

More on 2nd law

• We can NEVER recycle or reuse high quality energy to do useful work.

• You get high quality matter and energy in your body, you use it and you add low quality waste matter and heat to the environment.