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Science MCT Review. Competency 2 Physical Science. Obj. 2a (DOK 1). Identify patterns found in chemical symbols, formulas, reactions, & equations that apply to the Law of Conservation of Mass.
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Science MCT Review Competency 2 Physical Science
Obj. 2a (DOK 1) • Identify patterns found in chemical symbols, formulas, reactions, & equations that apply to the Law of Conservation of Mass. • Chemical symbols and chemical formulas of common substances such as NaCl (table salt), H20 (water), C6H12O6 (sugar), O2 (oxygen gas), CO2 (carbon dioxide), and N2 (nitrogen gas) • Mass of reactants before a change and products after a change • Balanced chemical equations such as photosynthesis and respiration
Chemical Formulas • Chemical Formulas show a combination of chemical symbols & numbers that indicates which elements & how many atoms of each element are present in a compound • H2O (Water) • C6H12O6 (Sugar/glucose) • O2 (Oxygen Molecule) • CO2 (Carbon Dioxide) • N2 (Nitrogen Molecule) Subscript: # of atoms
What is the molecule? • NaCl • H20 • C6H12O6 • O2 • CO2 • N2 • CH4
Law of Conservation of Mass • The Law of Conservation of Mass states that mass can neither be created nor destroyed
Balancing an Equation • Ex. 2H2 + O2 2H2O Reactant Product
2.a. Balancing Equations • Zn + 2HCl ZnCl2 + H2 • How many hydrogen molecules will be produced if there is 1000 HCl molecules in the reactant side of this balanced equation?
Obj. 2.a. Photosynthesis and Respiration Photosynthesis carbon dioxide + water + sunlight oxygen + glucose 6 CO2 + 6H2O 6O2 + C6H1206 Respiration • oxygen + sugar carbon dioxide + water + energy • 6O2 + C6H1206 6CO2 + 6 H2O
Obj. 2b (DOK 2) • Predict the properties and interactions of given elements using the periodic table of the elements. (DOK 2) • Metals and nonmetals • Acids and bases • Chemical changes in matter (e.g., rusting [slow oxidation], combustion [fast oxidation], food spoilage)
Element Keys • Label the tag 7 N Nitrogen 14.007 Symbol Atomic Mass Protons + Neutrons Atomic Number # of Protons Element Name
Elements are arranged in a Periodic Table • Arranged by increasing atomic Number (proton #) • Rows are called periods & are labeled 1-7 • There are 18 columns • Each column contains a group or family of elements • Groups are elements that have similar physical or chemical properties
Period Elements are arranged in a Periodic Table
Types of Elements • Metals • Nonmetals • Metalloids
Metals • Makes up the majority of elements • Ex. Copper (Cu) • Found on the left side of the periodic table in groups 1-15 • Physical Properties of metals • Malleable: can be hammered or rolled into flat sheets or other shapes • Ductile: can be pulled out or drawn into a long wire • Conductivity: have the ability to transfer heat or electricity to another object • Some are magnetic (Iron, Cobalt, & Nickel) • Have luster (shine)
Non-metals • Found on the right side of the periodic table • Ex. Carbon (C) • Physical properties are opposite of metal properties • Poor conductors of heat & electricity • Brittle: shatter easily • Dull
Metalloids • Found along a stair-step pattern between the metals & non-metals beginning in group 13 • Ex. Silicon (Si) • Also known as Semi-metals • Share properties of both metals & non-metals
What other elements have similar properties to Phosphorus (#15)? • What type of element is calcium? • What group would an element that is brittle & not a good conductor of electricity be in? • What does the staircase divide?
Chemical Bonds • Elements bond to other elements to become stable by having a full valence shell • Most elements need 8 valence electrons to become stable • Elements will become stable by losing, gaining, or sharing valence electrons • Elements that lose electrons become positively charged ions • Elements that gain electrons become negatively charged ions • Types of bonding: • Ionic • Covalent
Ionic Bonding • Ionic bonding: occurs when an atom that no longer has a neutral charge because it has lost or gained an electron • Typically between a Metal (looses) & Non-metal (gains) • Ex. Na+Cl-
Covalent Bonding • Covalent bonds are chemical bonds that form from atoms that share valence electrons to become stable • Occurs between two or more nonmetals • Ex. H2 , Cl2 , H2O , C6H12O6
Element Families have similar chemical properties • Alkali Metals: Group 1; 1 valence electron • Alkaline Earth Metals: Group 2; 2 valence electrons • Halogens: Group 17; 7 valence electron • Noble Gases: Group 18; 8 valence electron
Properties of Acids & Bases • An acid is a compound that produces hydrogen ions in water (H+) • The greater the concentration of H ions produced, the stronger the acid • A base is any compound that produces hydroxide ions (OH-) in water. • The greater the concentration of OH- produced, the stronger the base.
Predicting Acids & Bases using the Periodic Table • H+ • combines with certain nonmetals (Halogens (group 17) • The weaker the bond the stronger the acid. • Ex. Fluorine & hydrogen (HF) weakest acid • Ex. Iodine & Hydrogen (HI) strongest acid Stronger acid
Predicting Acids & Bases using the Periodic Table • hydroxide ion (OH-) • joins with a metal • group 1 (alkali metals) • group 2 (alkaline earth metals) • The weaker the bond the stronger the base. • Ex. Potassium Hydroxide (KOH) weakest base • Ex. Lithium Hydroxide (LIOH) Strongest base Stronger base
What element will ionically bond with sodium (#9)? • What 2 elements can covalently bond? • Identify the following as an acid or a base • HI • LiOH • How many Sodiums will be needed to bond with one oxygen atom? • What type of bond will this be?
Obj. 2c (DOK 2 & 3) • Distinguish the motion of an object by its position, direction of motion, speed, and acceleration and represent resulting data in graphic form in order to make a prediction.
Graphing Speed • Formula: Speed = distance÷ time (S=D/T) • Speed can be graphed on a distance-time graph • The steeper the line on a distance-time graph, the greater the speed • A horizontal line means no change in position, which makes the speed “zero” at anytime on the graph
Example Graph • Which student is moving fastest? • Which student has no motion?
Velocity • Velocity is the speed of an object and the direction of its motion. • Unit is same as speed, but includes direction • 10km/h east
Acceleration • Acceleration occurs when an object changes its motion (velocity changes) • Speed up - 50m/h to 60m/h (positive) • Slow down – 45m/h to 40m/h (negative) • Acceleration is in the opposite direction of the motion • Change in direction – north to east • Basket ball thrown from the free-throw line
Graphing Acceleration • Identify the Motion • A B C
Obj. 2f (DOK 2) • Recognize Newton’s Three Laws of Motion and identify situations that illustrate each law • (e.g., inertia, acceleration, action, reaction forces).
Newton’s first law • 2 parts • An object will remain at rest until an unbalanced force is applied to the object • Ex. Skateboard pushed in motion • An object in motion will remain in motion at a constant rate until an unbalanced force is applied to the object • Ex. Moon moves in a consistent pattern • Known as the “law of inertia” • Inertia is the tendency of an object to resistchange in its motion • Ex. Applying breaks in a car and your body goes forward
Newton’s 2nd Law • Newton’s second law of motion connects force, acceleration, and mass • an object acted on by a force will accelerate in the direction of the force • acceleration equals net force divided by mass. • Ex. An empty skateboard verses a person standing on a skateboard: Which one will you have to push harder to go the same distance? • Formula: (a = fnet÷ m) or (fnet = m x a)
Newton’s 3rd Law • Newton’s third law of motion states that forces always act in equal but opposite pairs called action/reaction forces • for every action there is an equal and opposite reaction. • Bounce a ball on the ground or playing pool • Action-reaction forces are always the same size but are in opposite directions and act on different objects. • When the mass of one object is considerably larger than the mass of another object, the action-reaction force is not noticeable. • When you push a wall or walk on the earth.
Which law? • Using an oar to move a canoe • Pushing a swing with more force to move your big brother than you did with your little sister • A rock is sitting on a hill until you push it causing it to roll Quiz 3rd 2nd 1st
Obj. 2d (DOK 2 & 3) • Relate how electrical energy transfers through electric circuits, generators, and power grids, including the importance of contributions from Mississippi companies.
Generating Electricity • Generators are devices that spin a coiled wire within a magnetic field to produce electricity • The mechanical energy of a spinning turbine is transformed into electrical energy for human use • Primary method for producing the electricity in homes, schools, & the community