Transcript Blitz Cards For MCT Review

Physical Science Review
Pearl Junior High School
8th grade Science
Obj. 2a - Conservation of Mass
 Matter cannot be created nor destroyed
 Therefore:
The number of atoms must be equal on
both sides of the equation
the mass of the reactants must equal the
mass of the products
Obj. 2a - Balancing Equations
 What coefficient is needed below in order to satisfy
the law of conservation of mass? (Hint: balance the
equation!)
CH4 + __ O2  CO2 + 2H2O
Obj. 2a - Balancing Equations
 How many molecules of Fe2O3 (iron oxide - rust)
will be produced if 3000 O2 molecules react in the
balanced equation below?
4Fe
+
3O2

2Fe2O3
Obj. 2a - Balancing Equations
If 15g of Zn reacted with 25g of HCl to
produce 20g of ZnCl2, how much mass of
H2 would be produced?
Zn
15g
+
2HCl
25g

ZnCl2 + H2
20g
?
Obj. 2a - Photosynthesis and Respiration
Photosynthesis
carbon dioxide + water (sunlight)
6 CO2 + 6H2O

oxygen + glucose
6O2
+ C6H1206
Respiration
Sugar
C6H1206
+
+
oxygen
carbon dioxide
6O2

6CO2
+ water
+ 6 H2O
+ energy
+ energy
Obj. 2a - Chemical Equations
(common compounds)
 NaCl - table salt
 H20 - water
 C6H12O6 – sugar (glucose)
 O2 – oxygen gas
 CO2 – carbon dioxide
 N2 – nitrogen gas
Obj. 2b - Periodic Table
Properties of Metals and nonmetals
Metals: on the left side of the periodic table in
groups
Malleable
Ductile
Good conductors of heat and electricity
Nonmetals: on the right side of the periodic
table in groups
Brittle
Poor conductors of heat and electricity
Obj. 2b - Important Groups
Group 1
Alkali metals (most reactive metals)
Group 2
Alkaline Earth metals
Group 3-12 Transition Metals
Group 17
Group 18
Halogens (most reactive nonmetals)
Noble gases (completely non-reactive
- 8 valence electrons)
Metalloids Touch the “zigzag” line; have some
properties of metals & some properties of
nonmetals
Where are the metals and nonmetals?
Groups
 Vertical columns
 Have similar properties
 Group Number = number of valence
electrons
 Metals are more reactive as you move DOWN
a group
 Nonmetals are more reactve as you move UP
a group
Obj. 2b - Types of Bonds
 Atoms bond in order to become more stable!!
 Ionic:
 between a metal & non-metal
 metal gives electrons to nonmetal so that they each have 8
 Ex: NaCl (Group 1 metal gives its valence electron to Group
17 nonmetal)
 Covalent:
 between two or more non-metals
 The nonmetals share valence electrons so that they each
have 8
 Ex: H2O (One oxygen atom shares a valence electron with
each of two hydrogen atoms)
Obj. 2b - Periodic Table
Oxidation: when a substance reacts with oxygen
Rusting (slow oxidation)
4Fe + 3O2  2Fe2O3
Combustion or burning (fast oxidation)
CH4 + 2O2  CO2 + 2H2O
Food spoiling (banana turns brown)
Obj. 2.c. - Motion
A distance vs. time graph shows an objects’ speed
(velocity).
constant speed
moving away
constant speed
moving toward
at rest
Obj. 2c - Acceleration: change in motion
A speed vs. time graph shows an object’s
acceleration.
 Label each:
speeding up
slowing down
constant speed
Obj. 2f - Newton’s Laws
 1st law (law of inertia): Tells what happens to
an object’s motion when balanced forces act on
it: An object in motion will remain in motion,
and an object at rest will remain at rest.
Car stops, but your body moves forward
An object moving in space will continue
(comet)
Obj 2f - 2nd Law of Motion
 2nd law (F=ma): Tells what happens to an
object’s motion when unbalanced forces act on it:
an object’s acceleration depends on its mass and
the amount of force exerted on it.
Kick two balls with the same amount of force
and the lighter ball will accelerate more.
Kick the same ball with different amounts of
force and the larger force will cause it to
accelerate more.
Obj 2f - 3rd Law of Motion
 3rd Law of Motion (action/reaction):
for every action there is an equal and
opposite reaction.
bird flies, rocket lifts off, skater
pushes off wall, balloon flies around
Obj. 2d
Power Grids
(Path of electricity through a power grid:
 High-voltage electricity is generated at the power
plant.
 The electricity is transmitted by transmission and
distribution lines.
 Electricity goes through a transformer on the utility
pole to lower the voltage before it enters the home.
 If a customer generates electricity at home (solar
panels, windmill), they can sell unused electricity to
the power company for other customers to use.
Obj. 2e
Electromagnetic Spectrum
 Radio: TV/radio (lowest energy)
 Microwave: used in cell phones, police radar, and for cooking
 Infrared: heat/thermal
 Visible: ROYGBIV (from longest to shortest wavelength)
 Ultraviolet (UV)
 Mostly blocked by ozone layer in atmosphere
 damages skin cells, causes skin cancer
 used to disinfect medical equipment and to kill bacteria and other
microorganisms in drinking water
 X-ray: pictures of bones/teeth; damaging to cells of living
things
 Gamma: treat cancer – highest energy
Obj. 2e Electromagnetic Spectrum