Physical Science EOC Review Marilyn Pendley, Instructor, CCCMC Modified by R. Kittrell Jan 2015 & 5Jan2016 1 2 Scientific Experimentation controlled experiment -Only one variable should be changed at a time. Manipulated (independent) variable – changed by the experimenter. Responding (dependent) variable – the effect that is measured. 3 Law vs. Theory • Develop a law – Law: Summarizes the outcome of several experiments that occur repeatedly and consistently. – Example: The spoiled food served at lunch makes people sick with a stomachache. • Develop a theory – Theory: Explanation for why a law exists. – Example: It is the bacteria in the spoiled food that makes people ill. 4 Types of Measurements 1. Length a. The distance from one point to another point. b. Base unit is the meter (m). c. Tool is the metric ruler. 2. Volume a. The amount of space a substance occupies. b. Base unit is the liter (L). c. Tools: metric ruler for regular solids or graduated cylinder for liquids. 5 3. Mass a. The amount of matter in a substance. b. Base unit - kilogram (kg). c. Tool is the balance. 4. Weight a. A measure of gravitational force on an object. b. Unit is the newton (N). c. Tool is the scale. 6 5. Time a. How long an event takes to occur. b. Unit is the second (s). c. Tool is the clock (stopwatch). 6. Temperature a. The amount of kinetic energy a substance has. b. SI unit is the Kelvin (K). c. Tool is the thermometer. 7 7. Density a. How compacted the matter is in a substance. b. Units can be g/mL, g/cm3, kg/m3. c. Density is a derived unit (it is made up of other types of measurement). d. D = m / v e. Objects float if their density is less than the density of the fluid they are in. 8 Matter comes in 3 phases Solid Gas Liquid 9 Solid Definite Shape Definite Volume 10 Liquid Indefinite Shape – takes the shape of the container Definite Volume 11 Gas Indefinite Shape – takes the shape of the container. Indefinite Volume – can expand and can be compressed. 12 Plasma • • • • • Plasma: a high energy gaseous state of matter. It is very unstable. Particles are moving extremely fast, free energy Most abundant phase of matter Only present under extremely hot/energetic situations • Example: Sun 13 CHANGES IN STATE • Melting: Solid to liquid • Boiling: Liquid to gas • Sublimation: Solid to gas – The above three require input of energy • Condensation: Gas to liquid • Freezing: Liquid to solid • Deposition: Gas to solid – The above three release energy 14 Change of Phase FIRST DO THIS Temperature Experiment By Clicking Here! Phase change Phase change To Understand this Graph CLICK HERE 15 PHYSICAL and CHEMICAL PROPERTIES Physical: • Property of a substance that does not change even if substance is altered. • Examples- melting point, odor, color, etc. Chemical: • Property of a substance that can only be observed because substance is changed. • Examples- combustibility, reaction with acid 16 Chemical or Physical Change? Chemical Change Physical Change • New substances formed with new properties • No new substances formed • Examples: • Examples: • Rusting • Gas forming during a reaction (bubbles) • A precipitant forming during a reaction • Ice melting • Water evaporating • Dry ice subliming into Carbon dioxide • Salt or sugar dissolving in water 17 18 CLASSIFICATION OF MATTER 19 ELEMENTS • contain only one type of atom • building blocks of matter • 115 known elements today, 90 which occur naturally • Found on periodic table – The first letter is always capitalized, the second letter is always lower case • Fluorine is F, not f • Cobalt is Co, not CO (which is carbon monoxide) 20 Compounds Compounds - 2 or more elements chemically combined to form a new substance with new properties Properties – The way a chemical substance looks and behaves 21 Mixtures and Pure Substances – A mixture has unlike parts and a composition that varies from sample to sample • A heterogeneous mixture has physically distinct parts with different properties. • A homogeneous mixture is the same throughout the sample – Pure substances are substances with a fixed composition 22 23 Electron_______ Cloud is a visual model An _________ of the most likely locations for electrons in an atom. www.unitedstreaming.com – Physical Science – Elements, Compounds, and Atoms An Orbital is a region of space around the nucleus where an electron is likely to be found. * An electron cloud is a good approximation of how electrons behave in their orbitals. 24 Lewis Dot Diagram •An electron dot diagram uses the symbol of the element and dots to represent the outer level electrons. •Electron dot diagrams are used also to show how the electrons in the outer energy level are bonded when elements combine to form compounds. 25 Atom the smallest particle making up elements 26 Atomic Structure Basics: • Protons: positively charged particles, weighing 1 atomic mass unit (1.67x10-24 grams) and located in the nucleus. • Neutrons: neutrally charged particles, weighing approximately 1 atomic mass unit and located in the nucleus. • Electrons: negatively charged particles , weighing zero atomic mass units, located in orbitals of the energy levels found outside the atomic nucleus 27 Atomic Number: • The number of protons • Play the Name the in an atom determines Atom Game at: what element it is. • http://www.learner.org • Add or subtract even /interactives/periodic/b one proton from an asics_interactive.html atom of any element and you no longer have the original element in any form. Now you have a different element! 28 Drawing an Atom of Carbon 6 C 12.011 Atomic # = # of p+ and # of eCarbon has 6 p+ and 6 e- Atomic Mass minus Atomic # = # of n0 Carbon has 6 n0 29 Drawing an Atom of Carbon eee- 6 p+ 6 n0 e- ee30 Periodic Table Basics: Essential Question: What are Horizontal Rows called? Answer: PERIODS 31 Electron Configuration • The “Period” number is equal to the number of energy levels in an atom • Remember: The number of electrons are equal to the number of protons in a neutral atom 32 What are Groups on the Periodic Table? Essential Question: Groups are also known as Families of Elements. They share chemical properties. WHY? Answer: They have the same number of outer shell electrons. 33 Electron Configuration • For Groups IA – VIII the group numbers are equal to the number of outer shell electrons or valence electrons • Group “IA” has ONE valence electron • Group “IIA” has TWO valence electrons; etc. 34 Name that GROUP: The Alkali Metals IA = one outer shell electrons therefore Oxidation state? +1 35 Name that GROUP: The Alkali Earth Metals IIA = two outer shell electrons Oxidation state? +2 36 Name that GROUP: The Noble Gases VIIIA = eight outer shell electrons (except Helium which has 2 but is FULL) therefore Oxidation state? NOT! 37 Name that GROUP: The HALOGENS The Salt Formers VIIA = SEVEN outer shell electrons therefore Oxidation state? -1 38 Name that GROUP: The Transition Metals B series = usually 2 or 3 outer shell electrons therefore Oxidation state? +2 or +3 39 Criss-Cross Method • Determine the charges/oxidation #’s for each element. • By criss-crossing the charges of the elements you can easily write the chemical formula • Example: Hydrogen + Oxygen – H + O IONS = H+1 + O–2 – Criss cross the oxidation # • just the numbers - not the + / - signs – Write the numbers as subscripts • bottom right of symbol Criss Cross Method This becomes H+1 O-2 CrissCross the numbers H2O1 Final: H2O • Where is the 1 in the final formula? Criss-Cross Method e- This becomes e- H+1 O-2 CrissCross the numbers H2O1 Final: H2O • Where is the 1 in the final formula? Criss-Cross Method - -You Try it! Mg + O Ca + P K+S C+H As + S C+O Criss-Cross Method You Try 1. 2. 3. 4. 5. 6. Mg + O Ca + P K+S C+H As + S C+O Mg2O2 MgO Ca3P2 Just like with Fractions in K2S math the CH4 Numbers will reduce! As2S3 C2H4 CO2 Criss-Cross & Polyatomic Ions • Sodium + Sulfate – Na + SO4 – Na+1 + (SO4)-2 Do the Criss-Cross Na2(SO4)1 Final: Na2(SO4) Chemical Bonding: • Three types of bonding Game: Ionic Bonding • Ionic • Covalent • Metallic Bonding Animations and short clips AWESOME MOVIE ON BONDING 30 minutes long 46 Ionic Bonding • Ionic Bonds: between oppositely charged atoms; usually on opposite sides of the periodic table (nonmetal and a metal) • transfer electrons • form networks, not molecules • conduct electricity Covalent Bonds • Covalent Bonds: share electrons; usually between 2 elements close on the periodic table (2 nonmetals) – nonpolar covalent bond: e- shared equally – polar covalent bond: e- shared unequally Metallic Bonding • “sea of electrons”: electrons can “float” freely between atoms; allows metals to conduct electricity well Rules for naming and writing chemical formulas 1. Metal name comes first 2. Change the ending of the second element to “ide” • If you have two nonmetals, use the prefixes: Mono – 1 Penta - 5 Di - 2 Hexa - 6 Tri - 3 Hepta - 7 Tetra – 4 Octa - 8 50 Which of the following is the correct name of a combination of sodium and iodine? • a) sodium chloride • b) sodium iodide • c) sodium iodine • d) iodine sodium 51 Transition Metal Naming • Transition metals show their charges as Roman Numerals because they can change charge!! FeO = Fe+2 + O-2 Iron (II) Oxide Fe2O3 = Fe+3 + O-2 Iron (III) Oxide 53 Chemical Reactions Types • Combustion: ALWAYS has O2 as a REACTANT! – AB + O2 AO + BO • Single-Replacement (single-displacement): • AX + B A + BX • Double-Replacement (double-displacement): • AX + BY AY + BX 54 Types of Chemical Reactions. Type of Reaction Synthesis Decomposition Definition Equation Two or more elements or compounds combine to make a more complex substance A + B → AB Compounds break down into simpler substances AB → A + B Single Replacement Occurs when one element replaces another one in a compound Double Replacement Occurs when different atoms in two different compounds trade places AB + C → AC + B AB + CD → AC + BD A = Red B = Blue C = Green D = Yellow Identifying Chemical Reactions Use colored pencils to circle the common atoms or compounds in each equation to help you determine the type of reaction it illustrates. Use the code below to classify each reaction. S = Synthesis D = Decomposition ____ P + O2 → P4O10 ____ HgO → Hg ____ Cl2 + + SR = Single Replacement DR = Double Replacement ____ Mg + O2 O2 NaBr → NaCl + Br2 → ____ Al2O3 MgO → Al + O2 ____ H2 + N2 → NH3 ____ Na ____ HgO + Br2 → NaBr ____ CuCl2 + H2S → + Cl2 → HgCl + O2 ____ KClO3 → KCl + ____ BaCl2 + Na2 SO4 → O2 NaCl + ____ C + ____ S8 BaSO4 + H2 → F2 → CuS + HCl CH4 SF6 58 Solubility 59 Acids & Bases • The strength of an acid or base depends on how many acid or base particles dissociate into ions in water. • Strong Acid/Base - + – 100% ions in water – strong electrolyte – HCl, HNO3, NaOH, LiOH • Weak Acid/Base • few ions in water • weak electrolyte • HC2H3O2, NH3 - + 60 pH Scale • pH – a measure of the concentration of H3O+ ions in solution – measured with a pH meter or an indicator with a wide color range IsotopesForms of an element with different numbers of neutrons (different masses) Isotopes of Hydrogen Protium- A#1 M#1 #N=0 Deuterium- A#1 M#2 #N=1 Tritium- A#1 M#3 #N=2 62 More Isotope stuff… A Mass Number Z Atomic Number 1 1 2 H 1 235 92 U X Element Symbol 3 H (D) 1 238 H (T) U 92 63 Radioactive Decay Radioactive decay results in the emission [or release] of either: • an alpha particle (a), • a negative beta particle (electron) (b-), • a positive beta particle (positron) (b+), • or a gamma ray (g). In a nuclear reaction the MASS and ATOMIC NUMBER must be the SAME on both sides of the equations Alpha Decay An alpha particle is identical to that of a helium nucleus. It contains two protons and two neutrons. A X Z A-4 4 Y He + Z-2 2 unstable atom alpha particle more stable atom Beta Emission A beta particle is a fast moving electron which is emitted from the nucleus of an atom undergoing radioactive decay. Beta emission occurs when a neutron changes into a proton and an electron. A X Z A Y + Z+1 proton stays in nucleus 0 e -1 beta particle (electron) Gamma Decay • When atoms decay by emitting a or b particles to form a new atom, the nuclei of the new atom may still have too much energy to be completely stable. These unstable atoms will emit gamma rays to release that energy. • There is no change in mass or atomic number A X Z A Z X + g 0 0 Decay Summary Reaction What happens? Alpha Decay a Lose Helium Nucleus Beta Decay b- Lose electron from nucleus (neutron turns into proton) Gammy Decay g Mass # Atomic # -4 -2 No change +1 Emit high energy gamma ray No change and either a or b particle No change Test questions may involve graphs like this one. The Most common questions are: "What is the half-life of this element?" Just remember, that at the end of one half-life, 50% of the element will remain. Find 50% on the vertical axis. Follow the blue line over to the red curve and drop straight down to find the answer: The half-life of this element is 1 million years. Another common question is: "What percent of the material originally present will remain after 2 million years?" Find 2 million years on the bottom, horizontal axis. Then follow the green line up to the red curve. Go to the left and find the answer. After 2 million years 25% of the original material will remain. Nuclear Energy Essential Questions: • Why is it worth the RISK?? • Tremendous OUTPUT of ENERGY!! • Fission or Fusion? •Fission! Atoms of U-235 are split •Use the link to see how Nuclear Fusion works: •Fusion! Atoms are joined or fused together. http://science.howstuffworks.com/fusion-reactor.htm/printable 71 Types of Energy • Mechanical Energy – Kinetic (motion) and Potential (stored) • Heat Energy • Chemical Energy • Nuclear Energy • Electromagnetic Energy – Light, Sound, Electricity, Magnetism 72 73 Heat energy: • Direction of Energy Flow? • HOT toward COLD 74 Calculating Q Q= Mass (m) X DT (change in temp) X Cp (Specific Heat) Mass- in grams (or an equivalent unit to the mass in Cp) DTemperature- (End Temp Co) – (Beg. Temp Co) Cp- J/g X Co (a chart with CP values will be provided or you will be given the Cp value in the problem) Q Practice Problem 1. If the temperature of 34.4 g of ethanol increases from 25 C to 78.8 C, how much heat has been absorbed by the ethanol? (The Cp of Ethanol is 2.44 J/g . C). Q= 34.4 g X (78.8 -25) X 2.44 J/g . C Q= 4515.7568 J ~ 4.52 X 103 J Why is subtracting end temp – beg temp SO IMPORTANT? To know if heat is being lost (-) or absorbed (+) Three Ways to Transfer Heat • Conduction Direct contact • Convection Cyclic Movement • Radiation Through empty space 77 Dist. Vs. Disp. • Distance – Actual path that an object takes – Cannot be negative • Displacement – Straight line from start to finish – Can be negative or zero Think about your charts made to calculate distance and displacement on the grid. Explain how an object can have a zero or negative displacement. Speed and Velocity • Speed: the rate at which an object changes position • m/s : SI unit for speed Instantaneous vs. Average • Instantaneous Speed: speed at a particular point in time • Average Speed: speed taken over a distance traveled Ex: Speedometer of a car Ex: Calculating your speed over an entire trip How is velocity different than speed? • Velocity is speed with a direction. Ex: traveling 60 km/hr North Two ways to change velocity: 1. Change speed (speed up/slow down) 2. Change direction (turn) Acceleration • Acceleration: is the rate of change in velocity Acceleration = change in velocity time a = ve – vb time • SI unit of acceleration = m/s/s or m/s2 Ways to Change Acceleration • Change Speed • Change Direction Can you have negative acceleration? Speed and Time Graphs Forces • A force causes an object to move, accelerate, change speed, or direction • The unit of force is the Newton (N). – 1 N = 1 kg x m/s/s Balanced & Unbalanced Forces • Balanced forces – opposite and equal forces acting on the same object – result in NO motion of the object • Unbalanced forces – two or more forces of unequal strength or direction acting upon on an object – results in motion of the object Types of Forces • Gravity • Friction • Fluid Pressure Forces • Air Pressure Falling Objects • A falling object will accelerate downward at 9.8 m/s/s (in a vacuum). However, in real life air resistance will gradually slow it down. • Terminal velocity is the top speed reached by a falling object. At terminal velocity air resistance is equal to gravitational pull. Circular Motion • According to Newton's 1st Law, an object will move in a straight line unless a net force causes it to do otherwise. • Therefore, an object moving in a curved or circular path, like a tetherball, must have a force pulling it in a circle. Work • Work is done on an object when a force is exerted on an object that causes the object to move some distance. – No work without motion – No work without force in the same direction Direction and force • Horse does not work on • Horse does work on the the rider – force not in cart - force and motion same direction in the same direction Force on person Force on cart motion motion Calculating work • Work = Force X Distance – Force units = Newton, N – Distance units = meter, m – Work units = Joule, J • J = N*m 4. Calculating Work 4. A woman lifts her 100-newton child up one meter and carries her for a distance of 50 meters to the child’s bedroom. How much work does the woman do? Work 100 N X 1 m= 100 N-m (the 50 meter carry is not in the upward direction the force is applied) Mechanical advantage • Mechanical Advantage is used to determine if using a simple machine would be better to accomplish work than not using a simple machine. – Example- would it be better to dig a hole with your hands or a shovel? • If M.A. > 1 than using the simple machine was beneficial. • If M.A. < 1 than it would have been better to NOT use the simple machine. Mechanical advantage • There are TWO ways to calculate Mechanical Advantage: – Ideal Mechanical Advantage (IMA) which uses distances to determine. – Actual Mechanical Advantage (AMA) which uses force to determine. The 6 Simple Machines Movable Machines Lever Pulley Non-movable Machines Inclined Plane Screw Wheel and Axle Wedge What does a simple machine do? • Make work easier by • Changing the applied force • Changing the distance over which the force is applied • Changing the direction of the effort force What does a simple machine NOT do? You cannot get more work output than work input! 3 Classes of Levers: Remember what is in the middle: F- 1st Class-Fulcrum nd R- 2 Class- Resistance E- 3rd Class- Effort Transverse waves A transverse wave is one in which the disturbance is perpendicular to the direction of travel of the wave. Examples: Light wave, waves on a guitar string. Longitudinal Waves Longitudinal wave is one in which the disturbance is parallel to the line of travel of the wave. Example: Sound wave in air is a longitudinal wave. The Nature of Sound Longitudinal Sound Waves Sound in air is a longitudinal wave that is created by a vibrating object, such as a guitar string, the human vocal cords, or the diaphragm of a loudspeaker. Constructive Interference of Sound Waves Wavelength = λ = 1 m Path difference = 0 Destructive Interference Wavelength = λ = 1 m Path difference = λ/2= 0.5 m Doppler effect • Change in frequency and pitch of a sound. • Due to the motion of either the sound source or the observer. • Listen! Doppler effect of sound Electromagnetic Waves • Transverse waves without a medium! • (They can travel through empty space) • Electromagnetic waves travel VERY FAST – around 300,000 kilometres per second (the speed of light). At this speed they can go around the world 8 times in one second. • • Waves or Particles? Electromagnetic radiation has properties of waves but also can be thought of as a stream of particles. – Example: Light • Light as a wave: Light behaves as a transverse wave which we can filter using polarized lenses. • Light as particles (photons): When directed at a substance light can knock electrons off of a substance (Photoelectric effect) Notice the wavelength is long (Radio waves) and gets shorter (Gamma Rays) Where is Magnetism Concentrated? Magnetism is strongest at the POLES 111 Magnetic Domains : Not aligned: Magnetic domains are ALIGNED in a permanent magnet : 112 What happens if you cut a magnet in half? 113 Electromagnets: • What Happens if you increase the number of coils in an electromagnet? • The magnet gets STRONGER! 114 Get in line! 115 Ways to charge an object: 1. Conduction- direct touching 2. Induction- getting inside field but not touching 3. Friction-rubbing two objects together (forms static electricity) 116 Answer key: A: PE = 40 J (since the same mass is elevated to 4/5-ths height of the top stair) B: PE = 30 J (since the same mass is elevated to 3/5-ths height of the top stair) C: PE = 20 J (since the same mass is elevated to 2/5-ths height of the top stair) D: PE = 10 J (since the same mass is elevated to 1/5-ths height of the top stair) E and F: PE = 0 J (since the same mass is at the same zero height position as shown for the bottom stair Note since PEgrav = m *• g • h Doubling of the height will result in a doubling of the gravitational potential energy. • A tripling of the height will result in a tripling of the gravitational potential energy. 117 Physics Portion • Make a given table that lists the information you are given. BE SURE to include the item you are to find! • USE the Reference sheet! Find the equation that fits what you have. • Put the item you need to find on one side of the equals sign. • Add the other numbers and punch in the calculator. • Double check the answer from the calculator! 118