Presentation on theme: "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."— Presentation transcript:
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
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?
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?
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.
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.
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 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
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.ogvhttp://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
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
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.