Transcript Recognizing types of matter, physical and chemical changes.

Recognizing types of matter,
physical and chemical changes.
http://www.classzone.com/books/earth_science/terc/content/in
vestigations/es0602/es0602page02.cfm
Find out about the rock cycle
H
Li
Be
Na
Mg
K
Ca
B
C
N
Al
Si
P
S
Cl
Ge
As
Se
Br
Ga
O
F
elements
Rb
Sr
In
Sn
Te
I
Pictures of elements and
compounds
elements
Pictures of elements and
compounds
Compounds
2 hydrogen atoms
equally share
electrons to form a
covalent bond.
All the diatomic
elements do this.
Diatomic elements
Which pictures show elements alone?
1 kind of element
2 kinds of elements
Gas phase
2 kinds of elements
Liquid or solid phase
Which pictures show compounds alone?
Compound gas
compound
solid
Compounds
liquid
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• This website has many, many quizzes that
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forget information through the years.
(SiH3)-1 + CH3Na → CH3Si3 +
Na+1
Chemical reactions require bonding and un-bonding of electrons.
Something new is made.
Usually the new product can’t go back to being the reactants
or original ingredients.
Chemical reactions
Chemical Changes
• Burning…C6H12O6 becomes CO2 and H2O
• Rusting…Fe and O2 become Fe2O3
• Fermentation…Some C6H12O6 becomes C2H5OH
• Tarnishing…Some silver and O2 becomes silver
oxide
• Digestion…Some polymers become monomers
• Respiration…Some O2 becomes CO2
The reactions on this page have been simplified for better understanding.
Ways to recognize chemical
changes or reactions.
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Change in color.
Bubbles appearing.
Change in temperature.
Light or sound.
A new product sinking to the bottom of the
combined liquids (precipitate.)
• Some of the original (reactant) is missing.
Some examples of chemical
changes are:
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iron turning into rust in moist air,
burning of anything,
exploding fireworks,
weathering of rocks if the rocks are
exposed to acid,
• extracting sulfur from car battery acid,
• making plastic from oil,
More examples of chemical
changes are:
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when an unused battery loses its charge,
rotting of an egg,
apple turns brown,
acid neutralizing a base,
digesting food,
toasting a marshmallow,
dying your hair,
http://www.nisd.net/secww/science/science-taks/quiz14/physical%20quiz.htm
An 8 question quiz
Some examples of physical
changes are:
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cutting a piece of paper,
ice melting,
boiling water,
sawing wood,
erosion, dissolving,
change of state (solid,liquid,gas),
drawing copper into a fine wire,
separating out distilled water from seawater,
More examples of physical
changes are:
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wet hair drying,
separating out oxygen gas from air,
bursting a balloon,
freezing water,
crushing a can,
formation of sedimentary rocks,
painting a car,
melting metal for a car,
rolling steel into sheets for a car body
Density: ratio of mass to
volume....or mass divided by
volume.
Dissolving: solvents surrounding
solutes to the point of becoming
‘invisible’.
Mixture: various compounds side
by side but NOT reacting (rebonding) with each other.
Heterogeneous: mixture that is
NOT uniform throughout.
Homogeneous: mixture that is
uniform throughout.
physical changes: solid to liquid to
gas. Breaking into smaller pieces
but NO reacting.
physical properties-- ex.: shiny,
green, boiling point, freezing point,
gaseous at room temperature.
A SIX QUESTION QUIZ. Try it! Answers
given at the end of the quiz.
http://www.roomd116.com/Taks%20Assign
ments/Physical%20&%20Chemical.pdf
Ways to separate mixtures
• Sifting
• Shaking…denser ones sink and less
dense ones float.
• Spinning…denser ones sink and less
dense ones float.
• Chromatography
• Electrical separation
Sifting
Shaking
Spinning
to separate things.
Water or another solvent
moving up paper
to separate a mixture.
Electricity zapped through a sample
may separate the mixture.
More ways to separate mixtures
• Change of state…two compounds in a
mixture are not likely to have the same
boiling points and freezing points.
• Distilling…separating by the different
boiling points.
Distilling one liquid out of another liquid.
Ways to separate mixtures
• Sometimes one part of the mixture is
soluble in water and the other isn’t.
Sand with salt and junk mixed in it.
Water carries the salt through the cloth.
• Sometimes one part of the mixture is
affected by magnets and the other isn’t.
Sorting trash with a magnet.
Picking up nails in a parking lot.
magnets
The experiment illustrates that iron and
sulfur combine to form —
A a nonmetal
B a compound
C a mixture
D an alloy
Equations not balanced for simplicity sake.
Which of these changes in rocks is a physical
change?
H2NO3 + CaCO3 → CO2 + H2O + CaN
A Acid rain damaging marble
B Iron in rock combining
Fe + O2 → Fe2O3
with oxygen to
form hematite
H2CO3 + CaCO3 → CO2 + H2O + Ca
C Carbonic acid weathering limestone
D An ice wedge shattering a slab of shale
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Equations not balanced for simplicity sake.
Which of the following
processes is an
example of a physical
change associated with
an oak tree?
A Decomposition of bark
by bracket fungi
Chemical change
C6H12O6 + O2 → CO2 + H2O
B Starches and sugars
being broken down
during energy Chemical change
chained(C6H12O6) → unchained(C6H12O6) + H2O
production
C Water and carbon
Chemical change
dioxide being
converted to glucose CO2 + H2O → C6H12O6 + O2
D Evaporation of water
from the surfaces of
Physical change- change of state
leaves
31
Chemical changes:
Bonding partners are changed.
Milk sugar + proteins → carbon dioxide + water + other chemicals
Which of the following is an example of
a chemical change?
F Ice cracking
G Sugar dissolving
H Milk souring
J Lead melting
Physical changes:
Getting smaller
Dissolving
Changing phases…solid,liquid,gas
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An unknown silvery powder has a constant
melting point and does not chemically or
physically separate into other substances.
The unknown substance can be classified
as —
A an element
can be chemically separated.
B Compounds
a compound
C a mixture
Mixtures and alloys can be physically separated.
D an alloy
29
Which of these describes a pollution-producing
process that involves Normal
only environment
a physical change?
Coal with
+ S +a Oxygen
→ water
COcontent
SOto
Hot
added
A Coal
high sulfur
isHburned,
2is+
3 a+river
2O → H2SO4
or lake.
producing gases that cause acid rain.
Warmed
Oxygen O
B Chlorofluorocarbons
are
released,
O3 → O2 + O1 with the
bubbles to
changing ozone in the upper atmosphere atmosphere.
into oxygen.
C Hot wastewater isThermal
discharged
into a lake,
pollution causes a physical change.
lowering oxygen levels in the water.
D NO
Nitrogen
oxide
emissions combine with
+
H
O
→
HNO
2
2
3
water vapor, producing nitric Decrease
acid. in dissolved oxygen
2
causes fish kill.
31
Oxygen (O2) is an example of —
An alloy is a mixture or solution of two metals.
A molecule
A an
alloy is two or more atoms bonded covalently
together.
B aUsually
molecule
included in the bonds are C, P and the
A salt is abonded
an ionictogether.
bond between a metal
C adiatomic
salt elements
and non-metal.
D a mixture A mixture is two substances
together but not bonding together.
A compound can be two or more elements
bonded together, with ionic or metallic bonds.
’03 10 #9
In the rock cycle, which of
these is a chemical change
involved with the formation of
igneous rocks?
May cause a chemical change
with pressure.
F Compression
of sediments
May resultloss
from chemical
changes.
G Heat
from
lava
Is the act of elements
unbonding
and with
rebonding.
May
cause
a
chemical
change
heat/friction.
H Subduction of plates
J Formation of minerals ’03 10 #36
The diagram shows physical
changes that occur in the water
cycle. Which of
Condensation
Precipitation
these shows
condensation?
Evaporation
AQ
Change of state….
B R physical changes
CS
Runoff
DT
’03 11 #21