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Science CASE 21 Review

Science CASE 21 Review. Competency 2 Physical Science. 2a 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 H 2 O (Water) C 6 H 12 O 6 (Sugar/glucose)

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Science CASE 21 Review

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  1. Science CASE 21 Review Competency 2 Physical Science

  2. 2a 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

  3. What is the molecule? • NaCl • H20 • C6H12O6 • O2 • CO2 • N2 • CH4

  4. Sample Question

  5. 2a. Law of Conservation of Mass • The Law of Conservation of Mass states that mass can neither be created nor destroyed

  6. Balancing an Equation • Ex. 2H2 + O2 2H2O Reactant Product

  7. 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?

  8. 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

  9. Sample Question

  10. Sample Question

  11. Sample Question

  12. 2b. Elements are arranged in a Periodic Table • There are 18 columns • Columns contain a group or family of elements

  13. 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

  14. Types of Elements • Metals • Nonmetals • Metalloids

  15. Metals • 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)

  16. Non-metals • Found on the right side of the periodic table • Physical properties are opposite of metal properties • Poor conductors of heat & electricity • Brittle: shatter easily • Dull

  17. Metalloids • Found along a stair-step pattern between the metals & non-metals beginning in group 13 • Ex. Silicon (Si)

  18. 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?

  19. 2b. 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

  20. 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-

  21. 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

  22. 2b. Properties of Acids & Bases • An acid is a compound that produces hydrogen ions in water (H+) • A base is any compound that produces hydroxide ions (OH-) in water.

  23. 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

  24. 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

  25. pH scale • The further from 7 the stronger the acid or base • Litmus paper turns blue with bases & red acids

  26. 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?

  27. Sample Question

  28. Sample Question

  29. Obj. 2c • 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.

  30. 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

  31. 2.c. Speed Graphs: Identify the motion. A B C D

  32. Velocity • Velocity is the speed of an object and the direction of its motion.

  33. 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

  34. Graphing Acceleration • Identify the Motion • A B C

  35. Example Graph

  36. Sample Question

  37. Sample Question

  38. Obj. 2f • Recognize Newton’s Three Laws of Motion and identify situations that illustrate each law • (e.g., inertia, acceleration, action, reaction forces).

  39. Newton’s first law • 2 parts • An object will remain at rest until an unbalanced force is applied to the object • An object in motion will remain in motion at a constant rate until an unbalanced force is applied to the object • 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

  40. 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)

  41. 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

  42. 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 • Stopping a grocery cart and the cereal box slides forward 3rd 2nd 1st

  43. Sample Question

  44. Sample Question

  45. 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.

  46. DC versus AC Current • DC current is when the electrical charge moves in one direction • Ex. Batteries • Always flow from the negative terminal to the positive terminal. • AC current is when the electrical charge flows in one direction, then in the reverse direction over and over again • Ex. Electrical current from the power plant to your home

  47. 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

  48. What spins the turbine • Energy is produced by burning fossil fuels to boil water produces steam that turns a turbine to generate electricity. • Burning fossil fuels causes a large amount of CO2 pollution

  49. Power Grids • A power gridis a transmission network that connects power plants to multiple Substations near a populated area.

  50. Transformers Device that transfers electrical energy from one circuit to another & changes the voltage by increasing or decreasing it

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