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TAKS
Objective 4
Matter and Change
States of
Matter
• All matter has mass and takes up space,
yet matter can exist in different states.
• There are three main states of matter
– 1. Solid
– 2. Liquid
– 3. Gas
Solids
• Every solid has a definite volume and a
definite shape.
• The particles are tightly compressed.
Liquids
• A liquid flows and takes the shape of its
container.
• Liquid matter has a definite volume but
no definite shape.
Gases
• Gases expand or
contract to fill the
space available to
them. They can
also compress to
fill smaller spaces.
• A gas has neither a
definite shape or a
definite volume.
Energy
Properties
of Fluids
Density
• Size and shape do not
change an object’s density.
• Example: a candle’s density
is determined, then you melt
the wax. What is the melted
wax’s density? The same as
the candle that was not
melted.
• The density of solids
usually decreases slightly
as temperature increases
because solids expand
when heated.
• Ice is less dense than water.
Because of this, the ice
floats in water.
• The formula for density is: d=m/v
And this line
means to
divide
Remember…
this line
means to
multiply
M
D
V
A block of maple wood with a volume of
405 cubic centimeters and a density of
0.67 g/cm3 is sawed in half. The density
of the two smaller blocks is now —
A one-fourth the original density
B one-half the original density
C two times the original density
D the same as the original density
A sample of an element has a volume of
78.0 mL and a density of 1.85 g/mL. What
is the mass in grams of the sample?
Record and bubble in your answer to the
nearest tenth on the answer document.
Use the formula page, D = m/v…now set
up in a triangle…
?
1.85
78.0
and solve…1.85 X 78.0 = 144.3
A
Buoyancy
of Fluids
Buoyancy
• Buoyancy is a measure of the upward
pressure a fluid exerts on an object.
Buoyant Force
HELP! I am
drowning
because the
buoyant
force is less
than my body
weight!!!
• If the buoyant force is
greater than its weight,
the object floats.
• If the buoyant force is
less than its weight, then
the object will sink.
Viscosity
of Fluids
Viscosity
• Viscosity is the measure of a material’s
resistance to flow.
• High-viscosity fluids take longer to pour
from a container than low-viscosity
fluids.
• Example: High-viscosity = syrup
Low-viscosity = water
Temperature Affects Viscosity
• As the temperature of a liquid is raised,
the viscosity decreases.
• Example: warm hot fudge is much easier
to pour than when it is cold
C
D
B
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The
Periodic
Table
Atoms are. . .
• The smallest part of a
single element.
• The basis of all matter.
• Made of mostly empty
space.
• Have a positive core or
nucleus.
• Have electrons
orbiting in clouds.
Parts of an Atom
• Protons
– Located inside the nucleus
– Have a positive charge
• Neutrons
– Located in the nucleus
– Have a neutral charge or no charge
• Electrons
– Orbit around the nucleus
– Have a negative charge
Atomic Number
• The atomic number is the number
of protons in the element’s
nucleus.
• Every atom of the same element
has the same atomic number.
• Ex: Every carbon atom has 6
protons
• The number of electrons in an
atom equals the number of
protons in that atom.
I see…the atomic
number is like a
person’s
DNA…it’s what
identifies us.
• When the atom has equal numbers of
protons and electrons it is said to be
electrically neutral.
• This is because the positive charges
equal the negative charges, therefore,
there is no charge.
Mass Number or Atomic Mass
• The mass number is the sum of the
number of protons and neutrons in the
nucleus
• Number of neutrons = mass number –
atomic number
Isotopes
• Atoms of the same element that have
different numbers of neutrons are called
isotopes
• To determine the number of neutrons in
an isotope:
• Mass number – Number of protons =
Number of neutrons
4 Basic Types of Elements
• Metals: found to the left of the stair-step
line
• Non-metals: found on the right side of
the stair-step line
• Metalloids: found along the stair-step
line
• Synthetic: made in the laboratory and
not yet found in nature – many of the
Actinide and Lanthanide series and very
large # elements.
Where are the metal elements?
Left of the Stair-step line!
Properties of Metals
• Metals are:
–Conductors
–Lustrous (shiny)
–Electron donors
–Malleable (rolled into
sheets – Aluminum foil)
–Ductile (pulled into wires)
Where are the nonmetals?
To the Right of the stair step line, and Hydrogen!
Properties of Nonmetals
• Nonmetals are brittle, insulators,
electron acceptors
• Usually form negative ions (except H)
• Many are gases at room temperature
• Found to the right of the stair-step
line
According to the periodic
table, which element most
readily accepts electrons?
•
•
•
•
A Fluorine
B Nitrogen
C Arsenic
D Aluminum
Fluorine only needs 1
electron to complete its
shell of 8, so it will accept it
from any other element
very very very easily. This
periodic property increases
as you move up and left in
the table, except for the
Noble Gases.
Use the Table provided!
What do the numbers mean?
11
Na
22.990
sodium
This is the atomic
number. It is the number
of protons in a single
atom of this element. By
the way, its also # of
electrons.
The symbol for this element.
This is the atomic mass, it is
the number of protons +
neutrons, or the mass of the
nucleus of an atom.
This is the name of the element.
Transition Elements
• The transition elements are located in
groups 3-12 of the periodic table.
• These elements are very hard, with high
melting points and boiling points.
Alkali Metals
• The alkali metals, found in group 1 of the
periodic table are very reactive metals.
• They have only one electron in their
outer shell. Therefore, they are ready to
lose that one electron in ionic bonding
with other elements.
Alkaline Earth Metals
• The alkaline earth elements are metallic
elements found in the second group of
the periodic table.
• All alkaline earth elements have an
oxidation number of +2, making them
very reactive.
Halogens
• The halogens are five non-metallic elements
found in group 17 of the periodic table.
• All halogens have 7 electrons in their outer
shells, giving them an oxidation number of -1.
• The halogens exist, at room temperature, in all
three states of matter:
– Solid- Iodine, Astatine
– Liquid- Bromine
– Gas- Fluorine, Chlorine
Noble Gases
• The noble gases are found in group 18 of
the periodic table.
• All noble gases have the maximum
number of electrons possible in their
outer shell (2 for Helium, 8 for all others),
making them the most stable.
Valence Electrons
• Valence electrons are those electrons
that an atom uses in forming a bond with
another atom.
• These electrons are found in the
outermost shell of an element.
• Look at your periodic table. You should
see roman numerals with A’s beside
them. These tell you the number of
valence electrons.
Valence electrons
• How many valence electrons does
Calcium have?
2
• How many valence electrons does
Oxygen have?
6
• How many valence electrons does
Chlorine have?
7
Important Note!!!!
• Atoms in the same group have similar
chemical properties because they have
the same number of valence electrons.
Which of the following groups
contains members with similar
chemical reactivity?
A Li, Be, C
B Be, Mg, Sr
C Sc, Y, Zr
D C, N, O
Lets look at the Table
provided.
• To have similar
A Li, Be, C
B Be, Mg, Sr
C Sc, Y, Zr
D C, N, O
chemical
properties of
any kind, they
must be in the
same Group or
Family.
• Groups are
columns, so the
answer would
be
•B
B
Oxidation Numbers
• The oxidation number tells how many
electrons an element can accept, lose, or
share when bonding.
• If it has a positive oxidation number, then
it tends to lose electrons.
• If it has a negative oxidation number,
then it likes to gain electrons.
Look at your periodic table and label
the oxidation numbers as follows:
+1
0
+2
These are the transition metals, and they
have varying oxidation numbers!
+3 +4 -3 -2 -1
Make sure you label these on the actual TAKS test!!
+1
0
+2
+3
+-4 -3
-2
-1
Chemical Reactivity
• Metals
increase in
reactivity left
and down.
• Nonmetals
become more
reactive up
and to the
right.
Fr
• Most reactive
metal is?
• Most reactive
F
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Remember that #
of electrons = # of
protons in a
neutral atom and
protons identify
the element
J
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Ionic
Compounds
Two Main Types of Bonds:
• Ionic
– Forms between a positively charged ion and
a negatively charged ion
– A metal and a nonmetal
• Covalent
– 2 nonmetals
– The electrons are shared
Ionic Compounds
• Ionic bond – the force that holds
oppositely charged particles together.
• Ionic compounds contain ionic bonds
• Ionic compounds consist of cations
(positive ions) and anions (negative
ions).
Ionic Formulas
• A formula is the symbols used to make
up a compound.
• Ex: NaCl = sodium chloride
• Calcium chloride’s formula is CaCl2. The
2 is a subscript, which means that it is
written below.
• A subscript tells the number of atoms of
the chemical written before it.
• If a subscript is not present, then the
subscript is assumed to be 1.
• Example: Fe2O3
– There are two atoms of iron and three atoms
of oxygen
The chemical formula for any compound tells
what elements it contains and the ratio of
the atoms of those elements.
Ions and Ionic Bonds
• When an element loses electrons it gets
a + charge associated with it. Refer to
your oxidation numbers on your periodic
table!!
• Ex: Mg2+ means that magnesium now
has a +2 charge or has lost 2 electrons.
• Superscript means written above. The
2+ written above Mg is the superscript.
• When a superscript is used, it tells the
charge that is on that element.
• The charge on an element can be
positive or negative
– If you lose electrons, then the charge is
positive
– If you gain electrons, then the charge is
negative
Remember!!!
• Ionic compounds are normally formed
between a metal and a nonmetal.
• Covalent bonds are normally formed
between nonmetals.
Rules for Writing Binary
Compounds
• 1. Write the symbol of the first element
which has a positive oxidation number
• 2. Write the symbol of the element which
has a negative oxidation number
• 3. Add subscripts so that the sum of the
oxidation numbers of all the atoms is zero
• You can use the criss-cross method as a
shortcut!
Example problem
• What is the formula for a compound containing
only aluminum and sulfur?
• 1. Write the symbol of the element with the
positive oxidation number followed by the
symbol of the element with the negative
oxidation number
– Al
S
• Look up the oxidation numbers and write them
above the symbols
– 3+
Al
2S
Criss-Cross Shortcut
+3
Al
2
-2
S
3
You still have to write down the symbols
and their oxidation numbers, but now you
can just criss-cross the oxidation
numbers and drop their signs to get your
formula!
Rules for Naming Ionic
Compounds
• 1. Write the name of the first element
• 2. Write the root of the second element
• 3. Add –ide to the end of the second
element
Roots
•
•
•
•
•
•
Chlorine – chlor
Fluorine – fluor
Nitrogen – nitr
Oxygen – ox
Phosphorous – phosph
Sulfur - sulf
Example problem
• What is the name of Li2S?
• Write the name of the positive element
– lithium
• Write the root of the second element
– sulf-
• Add –ide to the end of the second
element
– Answer: lithium sulfide
Water
Water is made up of 2 Hydrogen
atoms covalently bonded to an
Oxygen atom.
H
Covalent
Bond
H
O
Covalent
Bond
Water is a polar molecule, which means
one end has a positive charge and one
end has a negative charge
Slighlty
positive
charge
H
+
H
O
+
Slightly
negative
charge
The polarity of water allows
it to easily dissolve ionic
compounds.
Water is the universal solvent !!!
Opposite
charges
attract
Opposite
charges
attract
Elements,
Compounds,
& Mixtures
Matter
• Anything that
has mass and
takes up
space.
–Dog, car,
computer,
candy
• Energy is
NOT matter
Matter is divided into 2
categories:
• Pure Substances
• Mixtures
Matter Flowchart
MATTER
yes
MIXTURE
yes
Is the composition
uniform?
Homogeneous
Mixture
(solution)
no
Can it be physically
separated?
PURE SUBSTANCE
no
Heterogeneous
Mixture
yes
Can it be chemically
decomposed?
Compound
no
Element
Pure Substances
• Element
– composed of identical atoms
– EX: copper wire, aluminum foil
Pure Substances
• Compound
– composed of 2 or more elements
in a fixed ratio
– properties differ from those of
individual elements
– EX: table salt (NaCl)
Mixtures
• Variable combination of 2 or more pure
substances.
Heterogeneous
Homogeneous
There are two types of
mixtures:
• Heterogeneousmixture is not the
same from place to
place.
– Chocolate chip
cookie, gravel,
soil.
• Homogeneous- same
composition throughout.
– Kool-aid, air, brass.
Mixtures
• Solution
– homogeneous
– very small particles
– particles don’t settle
– EX: rubbing alcohol
Decide if the substance is
Element, Compound , or Mixture?
1. Water
1. Compound
2. Compound
2. Table Salt
3. Oxygen
3. Element
4. Dirt
4. Heterogeneous Mixture
5. Air
5. Homogeneous
Mixture/Solution
Let’s try a few more!
6. Copper
6. Element
7. Soda
7. Solution/Homogeneous Mixture
8. Steel
8. Solution/Homogeneous Mixture
9. Acid Rain 9. Heterogeneous Mixture
10. Vanilla Ice-cream
10. Homogeneous
Mixture
H
Physical and
Chemical
Changes
Changes in Matter –
Physical or Chemical?
• Physical changes are changes in the state
of matter. They do not change the
substance. (Melting, boiling, condensing,
freezing, cutting)
• Chemical changes are reactions that result
in new products with new properties.
Physical Changes
• Physical changes are about energy and
states of matter.
• When you step on a can and crush it, you
have forced a physical change. The
shape of the object has changed. It
wasn't a change in the state of matter,
but something changed.
Chemical Changes
• When iron (Fe)
rusts you can
see it happen
over a long
period of time.
The actual
molecules have
changed their
structure (the
iron oxidized).
Changes in Matter –
Physical or Chemical?
• Physical changes
• Cutting a piece of
wood does not
change the wood, it
is simply smaller.
• Chemical changes
• When a different
substance is
produced than what
was present at the
start, a chemical
change has
occurred.
Let’s try some problems…
1. Cutting your hair
1. physical
2. Fire burning
2. chemical
3. Ice melting
3. physical
4. Water evaporating
4. physical
5. Tomato rotting
5. chemical
Let’s try some more…
6. Sodium combines with chlorine to produce table salt.
6. chemical
7. Glass breaking
7. physical
8. Food digesting
8. chemical
9. Water is broken down into hydrogen & water
9. chemical
10. photosynthesis
10. chemical
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Conservation of Mass
• The Law of Conservation of Energy says that
energy can neither be created nor destroyed.
• Massreactants = Massproducts
According to the law of conservation of
mass, how much zinc was present in
the zinc carbonate?
Since matter can not be created or destroyed in
A 40 g
B 88 g
C 104 g
D 256 g
chemical reactions, the mass on both sides of the arrow
must be equal. So 64g + 192g = 256g and 152 g + Zinc = 256g
There must be 104g of Zinc. Answer C.
C
Balancing
Chemical
Equations
Chemical Reactions
• A chemical reaction is a change in which
one or more substances are converted to
different substances
Chemical Reactions
Since matter can not be Reactants  Products
created or destroyed,
chemical reactions
must be balanced in 100g total = 100g total
terms of mass.
The amount of mass
you start with must be
equal to the mass of
the products.
Counting Atoms
• Whole numbers written in front of formulas
are called coefficients. For example,
4 C6H12O6 indicates that there are 4
molecules of glucose sugar.
• To determine how many total atoms of each
element are present, multiply the
coefficients by the subscripts for each
element.
• 4 C6H12O6 would contain 24 atoms of carbon
(4 x 6), 48 atoms of hydrogen (4 x 12), and
24 atoms of oxygen (4 x 6).
• Reactants – the chemicals that will react
– They are to the left of the arrow
• Products – the chemicals that are
produced
– They are located to the right of the arrow
• Reactants
Products
Chemical Equation
• A chemical equation is an expression
that describes a chemical reaction using
chemical formulas and other symbols
• H2 + O ------ H2O
To balance equations:
• The number of atoms of each type of
element on the reactant side (left of the
arrow) must be equal those on the product
side (right side of the arrow).
2 H 2 + O2
2 H 2O
• There are 4 hydrogen atoms on the left (2 H2)
and 4 hydrogen atoms on the right (2 H2O)
• There are 2 atoms of oxygen (O2) on the left
and 2 atoms of oxygen on the right (2 H2O).
When a subscript is missing, it is
understood to be 1.

• Coefficients are the numbers that are
placed beside the chemical formulas to
balance chemical equations
• 2H2 + 2O ------ 2H2O
– The underlined numbers are the coefficients
Balanced Chemical Equations
• Has the same number of atoms of each
element on both sides of the chemical
equation
• You can NEVER change the subscripts in a
chemical equation!
• You must instead place whole numbers in
front of the chemical formulas!
• If there is no coefficient, then it is assumed to
be one.
Rules for Balancing Chemical
Equations
• 1 – under the reactants, list each element’s
symbol
• 2 – calculate how many atoms are associated
with each element
• 3 – repeat steps 1 and 2 for the products
• 4 – begin adding coefficients in front of the
chemical formulas to try to get the same
number of atoms on each side
• HINT: do NOT try to balance hydrogens
and oxygens first! Balance all other
elements first!
• 5 – double check that all elements on the
reactant side match their counterpart on
the product side of the equation
Example
• __C3H8 + __O2 ------- __CO2 + __H2O
C=
C=
H=
H=
O=
O=
• __C3H8 + __O2 ------- __CO2 + __H2O
C=3
C=1
H=8
H=2
O=2
O=3
• __C3H8 + __O2 ------- __CO
3 2 + __H2O
C=3
C=1 3
H=8
H=2
O=2
O=3 7
Make sure that you
recount not only your
C’s, but also your O’s!!!
•__C3H8 + __O2 ------- __CO
3 2 + __H
4 2O
C=3
C=1 3
H=8
H=2 8
O=2
O = 3 7 10
• __C3H8 + __O
3 2 + __H
4 2O
5 2 ------- __CO
C=3
C=1 3
H=8
H=2 8
O = 2 10
O = 3 7 10
2K
+ 2 H2O  2KOH + H2
19 What is the coefficient for H2O
when the above equation is
balanced?
• A1
• B2
• C3
• D4
Balance the equation below, the boxes
should get the coefficients.
2
2
C
H
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Solubility &
pH
Solubility
• Solubility of a substance is expressed as
the maximum number of grams of a
substance that will dissolve in 100 g of
solvent at a certain temperature.
• Solubility usually increases with
temperature.
• Solutes have different solubility values.
Solubility
–S o l v e n t - t h e m o s t
abundant substance
in the solution.
–S o l u t e - t h e l e a s t
abundant substance
in the solution.
– Water is known as the Universal
Solvent!
Solutions
• A solution contains a solute dissolved in
a solvent.
• A solute = the substance being dissolved
• A solvent = the substance that does the
dissolving.
• Usually the solvent is present in the
greatest amount.
Types of Solutions
• An unsaturated solution is any solution that
can dissolve more solute
• A saturated solution is a solution that has
dissolved all the solute it can normally hold at
a given temperature
• A supersaturated solution contains more
solute than a saturated one at any given
temperature. The excess solute crystallizes.
The three methods to increase the
rate of solution for a solid are?
•Heat it!
•Crush it!
•Stir it!
Rate of Dissolving
(Solid and Liquid)
• Stir a solution: this speeds up the
dissolving process because there are
more collisions between particles.
• Crushing, grinding, or breaking the
solute into smaller pieces.
• Increase the temperature
All of these can affect the rate at
which a solid dissolves in water
except —
A decreasing air
pressure
B stirring the water
C increasing the
temperature of the
water
D using larger
crystals of the solid
The three methods to increase the
rate of solution for a solid are?
• Heat it! C
• Crush it! D slows
it
• Stir it! B
• So this eliminates
choices B, C & D
• Which will NOT
change it?
• A
Answer choices were:
A decreasing air
pressure
B stirring the water
C increasing the
temperature of the
water
D using larger crystals
of the solid
A 0.2 g crystal of gypsum dissolves
very slowly in 100 mL of water while
the water is stirred. Which of these
would cause the gypsum to dissolve
faster?
What are the 3 ways to
F Decreasing the
water temperature
G Stopping the
stirring
H Lowering the air
pressure
J Crushing the
crystal
increase the rate at
which a solid
dissolves?
Heat it!
Crush it!
Stir it!
ANSWER?
J
• A solubility curve
shows the amount of
each solute that will
dissolve in 100g H20
at each temperature.
• Saturated is any point
on the line.
• Unsaturated is below
the line.
• Supersaturated is
above the line.
Grams solute/100 g H2O
How much solute will dissolve?
J
B
51 At which
temperature
do KBr and
KNO3 have
the same
solubility?
A 27°C
B 48°C
C 65°C
D 80°C
Try this one!
C
49 According to the
graph, about how much
hemoglobin would be
saturated at an O2
pressure of 7.3 kPa?
A 32%
B 67%
C 89%
D 92%
B
Concentrated or Dilute?
• A concentrated
solution has as little
solvent as possible.
• A dilute solution has
added solvent.
• After adding more
solvent, there is still
the same mass of
solute that you
started with.
Concentrated
• Kool-aid is
concentrated in the
package, but when
you mix it with water,
you are now diluting
it!
pH is a measure of the
Strength of Acids & Bases
• Acids have 0-6.99 pH
• Bases have 7.01-14 pH
• Litmus paper turns red
in acids and blue in
bases
Remember!!!!
• Acids produce H+ ions
• Bases produce OH- ions
• Therefore the higher the concentration of
H+ ions the more acidic it is.
• And the higher the concentration of OHions the more basic it is.
Higher pH levels means?
33 Two clear solutions are placed in
separate beakers. The first solution has a
pH of 4, and the pH of the second solution
is unknown. If the two solutions are mixed
and the resulting
pHthat
is 5,
the second
Remember
bases
solution must
have
release
OH-—
(hydroxide
ions) and solids
acids release
A fewer suspended
H+ (hydrogen ions) when
B a lower temperature
in solution
C more dissolved salt (NaCl) particles
D a higher concentration of OH– ions
F
B
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