Science MCT Science MCT ReviewReview

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

Sample Question

Law of Conservation of Mass

The Law of Conservation of Mass states that mass can neither be created nor destroyed

Balanced

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

Sample Question

Sample Question

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

Elements are arranged in a Periodic Table

Period

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

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?

Sample Question

Sample Question

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

2.c. Speed Graphs: Identify the motion.

D

ACB

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

Example Graph

Sample Question

Sample Question

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

Sample Question

Sample Question

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

Sample question

Sample Question

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

Sample Question

Sample Question