Science MCT Review Science MCT Review Competency 2 Physical Science
Dec 14, 2015
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
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 H2O= H2O + H2 O
(4 H) + (2 O)
2 H2 = H + H
H2 = H + H
(4 H)
1 02 = O + O
( 2 O)
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
Nitrogen14.007
Symbol
Atomic MassProtons + 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
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
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
Predicting Acids & Bases using the Periodic Table
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
• Which student is moving fastest?• Which student has no motion?
Example GraphDistance Verses Time
0
1
2
3
4
5
6
1 2 3 4 5 6
Time in seconds
Dis
tan
ce in
met
ers
Student A
Student B
Student C
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
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 resist
change in its motion• Ex. Applying breaks in a car and your body goes forward
Newton’s 2nd LawNewton’s second law of motion connects
force, acceleration, and mass an object acted on by a force will accelerate
in the direction of the forceacceleration 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 LawNewton’s third law of motion states that
forces always act in equal but opposite pairs called action/reaction forcesfor 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?
1. Using an oar to move a canoe
2. Pushing a swing with more force to move your big brother than you did with your little sister
3. A rock is sitting on a hill until you push it causing it to roll
Quiz
3rd
1st
2nd
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
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 pollution
Power Grids
• A power grid is a transmission network that connects power plants to multiple Substations near a populated area. – Allows distant energy sources (such as
hydroelectric power plants) to be connected to consumers in population centers
Transformers
Device that transfers electrical energy from one circuit to another & changes the voltage by increasing or decreasing it
Path of Electricity through a Power Grid
• Power Plant• Substation ( there are several
along the way)• Transmission Lines ( high & low
voltage)• Transformer (lowers voltage
before entering the home)• Junction Box on the home
(brings it into the home)• Outlet (sends it to electrical
devices)• Electric circuit for a blow dryer
Obj. 2e (DOK 2)
Contrast various components of the electromagnetic spectrum and predict their impacts on living things. (e.g., infrared, visible light, ultraviolet)
Contrasting EM Waves
• Gamma: carry the most energy• Shortest wavelength & highest frequency• Kills living cells• Used to treat cancer
Gamma rays at a Black Hole
Contrasting EM Waves
• Ultra-Violet (UV) rays: energy has both positive and negative effects on living organisms• Prolonged exposure causes sunburns by damaging the
epidermis layer of skin, damages sight, & can lead to skin cancer
• Ozone layer helps filter out of the atmosphere
• Used to sterilize medical equipment
• kill bacteria in water
Contrasting EM Waves
• Visible Light rays: the only part of the spectrum that is detectable by the human eye• Order from longest wavelength to shortest
• red, orange, yellow, green, blue, indigo, violet
• Roy G Biv
Contrasting EM Waves
• Infrared: Primary source is heat and thermal radiation• body gives off heat
• Fire burning
• Heat lamp
Contrasting EM Waves
• Radio waves: carries the least amount of energy • longest wavelength & lowest frequency
• Used to transport information by converting it to electrical signals
Put the following in order from lowest energy to highest energy &
Write one key Word/phrase for Each
• Gamma rays• Infrared• Red • X-rays
•Radio•Ultraviolet•blue