Structure

1
Structure Properties of Matter

• Science TAKS Review
• Objective 4

2
Fluids a substance that can flow and take shape
of its container.

• Gases can be compressed

• Liquids diffuse slowly (spread out evenly)

3
The density of steel is the same! Size doesnt
matter!
Density of Steel
steel bar
4
Which one floats? Why?

• Density of Water 1.00 g/mL
• Density of Ice 0.92 g/mL

Ice! Because it is less dense.
5
Predict the correct floating order of the
substances as they would appear in the Density
Column.
6
Is the bar really gold or fools gold?Find the
density of the bar if the mass is 1891.4 g and
the dimensions are 3.5 cm by 3.5 cm by 8.0 cm.

• Gold has a density of 19.3 g/cm3
• V L x W x H

D m/v 1891.4 g / 98 cm3 19.3 g/cm3 Yes its
gold!
m
d
v
7
Is the Silver Surfer really made of silver? We
obtained a sample with a mass of 262.5 g.
Platinum 21.5 g/cm3Silver 10.5 g/cm3Tin 7.3
g/cm3

• Find the volume by water displacement.

d m/v 262.5 g / 25 cm3 10.5 g/cm3 It is
Silver!
m
d
v
8
Viscosity
is the resistance to flow.
Which is more viscous?
warm syrup or cold syrup?
Cold syrup (high viscosity), because of the
strength of attraction between the particles.
9
Buoyancy
is the tendency of a less dense substance to
float in a more dense liquid.
Boats are made so that they have a lower density
than water.
10
Nonmetals
?Metalloids?
Metals
11
Properties of metals and nonmetals

• Metalloids have both metallic and nonmetallic
  characteristics along the staircase.
• Boron, Silicon, Germanium, Arsenic, Antimony,
  Tellurium, Astatine,

12
Groups or Family Names
1) ALKALI METALS
2) ALKALINE METALS
17) HALOGENS
18) NOBLE GASES
TRANSITIONMETALS
Inner earth metals
13
( protons) ?Atomic No.
14 Silicon
Si 28.086
?Element Symbol
?Atomic Mass
?Element Name
Groups (down)
Atoms are Neutral (protons electrons)
How many protons? How many electrons?
14
Periods (across)
14
14
Structure of The Atom

• Nucleus is small, dense, and positively charged.

• Electrons are located outside the nucleus in an
  electron cloud.

Mass Number
15
Sodium Isotopes
11 Na 22.99 Sodium
?Which is the most common isotope?
Na-23
11

• 1) Atomic number?
• 2) Mass number?
• 3) No. of Neutrons?

• 4) Atomic number?
• 5) Mass number?
• 6) No of Neutrons?

11
23
24
12
13
16
Electrons in Energy Levels
17

• What is the most common isotope?
• How many protons?
• How many electrons?
• How many neutrons?
• How many electrons in the 1st energy level?
• How many electrons in the 2nd energy level?
• How many electrons in the 3rd energy level?

Cl
Cl-35
17
35.45
17
18
2
8
7
17
Valence Electrons are the electrons in the
highest energy level.
18
Number of Valence Electrons

• Valence Electrons
• Are electrons in the highest energy level. The
  noble gases have 8 electrons.

• All elements will gain, lose, or share electrons
  to end up with 8 electrons like the noble gases.
  
• This is called the Octet Rule.

19
Net Ionic Charges Metals will lose electrons to
form positive ions. Nonmetals will gain electrons
to form negative ions.
20
Ionization Energy energy required to remove an
electron.
Metals easily lose e-
21
Electronegativity measure of an atoms
attraction for electrons.
Nonmetals easily gain e-
22
Atomic radii size of the atom.
Atomic Radii decreases
Atomic Radii decreases
23
Chemical Reactivity

• Metals increase in reactivity left and down.
• Most reactive metal is?
• Nonmetals become more reactive up and to the
  right.
• Most reactive nonmetal is?

Fr
F
Noble Gases are inert gases (dont react easily)
24
Properties of Ionic and Covalent Compounds
25
Ionic Bonds
Ionic Bond is a chemical bond between a ( ion)
and a (- ion). Atoms transfer electrons. Bond
is usually between a metal (gives up e-) and a
nonmetal (receives e-).
A B gt A B (transfer of
electrons)
26
Covalent Bonds
Covalent Bond is a chemical bond between two
atoms sharing electron pairs. Bond is usually
between nonmetals.
A B gt AB (sharing of
electrons)
27
Metallic Bonds
Metallic Bond - a bond resulting from the
attraction between positive ions and surrounding
mobile electrons. In solid and liquid
metals, metal atoms give up electrons, however
they are free to move throughout the material.
e-
28
Simple Ionic Compounds

• Naming Compounds
• Name the metal, then the nonmetal, change the
  ending to ide .
• Ex. Na2S ? Sodium sulfide
• Ex. AgCl ? Silver Chloride
• Writing Compounds
• Make sure positives and negatives add up.
• Ex. Sodium chloride Na1 Cl1- ? NaCl
• Ex. Calcium bromide Ca2 Br1- ? CaBr2

29
How many atoms do you need?
O2-
Al3
O2-
Al3
O2-

• You need 2 Al atoms 3 O atoms Al2O3

30
Simple Covalent Compounds

• Use prefixes to indicate the number of atoms of
  each element, change the ending to ide .
• Naming Compounds
• Ex. CCl4 ? Calcium tetrachloriide
• Ex. N2O ? Dinitrogen monoxide
• Writing Compounds
• Ex. Phosphorous pentachloride ? PCl5
• Ex. Carbon monoxide ? CO

Prefixes 1 mono 2 di 3 tri 4 tetra 5
penta 6 hexa
31
Acid Compounds

• Use prefix hydro and the stem ending ic.
• Naming Compounds
• Ex. HCl ? Hydrochloric acid
• Writing Compounds
• Ex. Hydrofluoric acid? HF

32
Has mass and volume (s, l, g)
One type of matter
More than one type of matter
Uniform throughout (solutions)
Not uniform throughout
One type of atom
Two or more elements
33
Properties of MatterProperty a characteristic

• Chemical properties
• characteristics of a substances ability to
  change into a different substance.
• Brainstorm a list of chemical properties as a
  group.

• Physical properties
• characteristics that can be observed or measured
  without changing the identity of the substance.
• Brainstorm a list of physical properties as a
  group.

Hint Think of gasoline!
34
Changes of Matter

• Chemical Changes
• A change that does produce a new substance.
• Usually not reversible.
• Ex Iron rusts forming iron oxide.

• Physical Changes
• A change that does not produce a new substance.
• Usually reversible.
• Ex Ice melts into water.

35
How do you know a chemical change has occurred?
Physical change begins in the mouth

• Evidence of a
• Chemical Change
• Energy (Heat)
• absorbed energy (endothermic)
• released energy (exothermic)
• Gas is produced (bubbles)
• Solid (precipitate) forms
• Odor or color change occurs

36
Why are these chemical changes?
37
Identify the following as a physical property, a
chemical property, a physical change, or a
chemical change.
Physical change
Chemical change
Physical property
Physical property
Chemical property
Physical change
Chemical property
Chemical change
38
Law of Conservation of Mass-Mass is neither
created nor destroyed!

• The total mass of the substances before they are
  mixed is equal to the total mass as a mixture.

64 192 256 g
Zn 104 g
39
Mass of the reactants Mass of the products
Always!

• 1CH4 2O2 ? 1CO2 2H2O
• 1 C, 4 H, 4 O 1 C, 4 H, 4 O
• (1x12.0) (4 x 1.0) (4x16.0) (1x12.0) (4 x
  1.0) (4x16.0)
• 80 g 80 g
• Ex How many grams of oxygen react with 16 g of
  CH4 to create 80 grams of products?

Reactants Products x g 16 g 80 g x 80-16
64 g O2
40
Balancing Chemical Equations
CH4 (g) O2 (g) ? CO2 (g) H2O (g)
Count the number of atoms on both sides of the
arrow.
1 CH4 (g) 2 O2 (g) ? 1 CO2 (g) 2 H2O
(g)
Place a coefficient in front of the compound to
get the same number of atoms in the
reactants and in the products.
41
Guided Practice

• Ex. 1 Mg HCl ? MgCl2 H2
• Ex. 2 KClO3 -?? KCl O2

Balanced Equation Mg 2 HCl ? MgCl2 H2
Balanced Equation 2 KClO3 -?? 2 KCl 3 O2
42
Types of Reactions

• 1. Synthesis
• A B ? AB
• 2. Decomposition
• AB ? A B
• 3. Single Replacement
• AB C ? AC B
• 4. Double Replacement
• AB MN ? AN MB
• 5. Combustion Reaction
• CxHy O2 ? CO2 H2O

43
Rates of Reactions

• The rate of a reaction is a measure of how
  quickly reactants turn into products.
• You can increase the rate of reaction by
• Increase the concentration of reactants
• Increase the surface area of reactants
• (By grinding substance in a mortar pestle)
• Increase the temperature
• Add a catalyst

44
Chemical Reactions vs Nuclear Reactions
45
Physical States of Water
Solid (Ice)
Gas (vapor)
Liquid (water)
Fluids can be gases or liquids. Fluids can flow
and take the shape of its container.
46
Change of State a physical change between
states of matter.

• Temperature influences changes of state.
• As temperature increases, the internal energy
  increases.
• S? L ? G

(Boiling)
Temperature
47
The Phase Change Graph
L G
Temp is constant

• Phase changes require a gain or loss of ___?
• When does it gain energy?
• When does it lose energy?
• At what points does the temperature stay the
  same?
• Can two states coexist?

S L
Temp is constant
48
Structure of Water
Polar Molecule Partial positive (?) and Partial
negative (??) charges.
Hydrogen Bonding
Hydrogen and Oxygen covalently bond to each other.
Polar dissolves Polar like dissolves like
49
Water as a Universal Solvent
Dissolves so many other substances.
Positive Ion Surrounded by oxygen (??)
Negative Ion Surrounded by hydrogen (?)
50
Dissolving Rate

• Increase rate of dissolving by
• Stirring or Shaking (moves molecules around)
• Crushing or grinding (reduces surface area)
• Heating (increases movement of molecules)

51
Emulsion a mixture that does not mix well
together. Ex. mayonnaise

• Emulsifier allows liquids to mix together that
  ordinarily would not. Ex. soap

52
Concentrations on Solutions
Solutions can be solids, liquids, or gases.
Unsaturated
Saturated
Supersaturated
More solvent than solute. Ex. Lightly sweetened
Solvent has dissolved all the solute it can hold.
Ex. Sweet tea
Solvent holds more solute than is normal. Ex.
Rock candy
Dilute solution made with little
solute. Concentrated solution made with a lot of
solute.
53
Solubility CurvesLook at KNO3

• Point on the line Saturated
• Point below the line Unsaturated
• Point above the line Supersaturated

54
Solubility Factors
Temperature Solids
Solubility increases as the temperature increases
for most substances (upward curves) Example
Dissolve sugar in hot tea vs. iced tea
55
Solubility Factors
Temperature Gases
Solubility of gases in water decreases with
increasing temperature.
Example Soda pop What happens when you
leave a soda out on a hot day?
Carbon dioxide gas will go out as the soda warms
up making it flat.
So keep your soda COLD!
56
Pressure Gases
Solubility Factors

• Solubility of liquids and solids isnt affected
  much.
• Gas solubility ALWAYS increases as pressure
  increases.
• The way to get gas to dissolve in liquid is to
  pressurize the mixture, meaning that the pressure
  inside a soda can is greater than the pressure
  outside the can.

57
Gas Laws
Boyle's Law
Increase Pressure Decrease Volume
Charles' Law
Increase Temperature Increase Volume
58
Electrolytic Behavior
Non-electrolyte (ex. pure water) No ions
present, thus, no electrical conductivity.
Weak electrolyte (ex.weak acid/base) Few ions
present, thus, poor electrical conductivity.
Strong electrolyte (ex. Strong acid/base) Salt
completely breaks apart to give more ions,
conduct more electricity.
59
Acids and Bases

• Bases are
• pH more than 7
• Bitter and Slippery
• Change Red litmus paper will to blue.
• Forms Hydroxide ions.

• Acids are
• pH less than 7
• Sour, like lemons
• Change Blue litmus paper to red.
• Forms Hydrogen ions

OH-
H
60
The pH Scale
Neutral
Acid
Base
Neutralization Reaction
Acid Base --gt Salt Water