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The Nature of Chemistry
Wednesday, October 21, 2015

11:52 AM

Science:
- Uses a process
- Objective
- Updated constantly
Pseudo Science:
- Lacks process
- Subjective
- Resistant to new information

- Chemistry is the "central science"
- Chemistry is important to society, but can be harmful at the same time
...


The Nature and Processes of Science Page 1

The Progress of Scientific Knowledge
Wednesday, October 21, 2015

11:57 AM

Things and knowledge we take for granted, had to be discovered by previous scientists
...
What types of scientists
would contribute to this discovery?
-

A biologist would identify and classify the sea sponge
...

A biochemist would test compounds for possible antitumor properties
A chemist would find a way to synthesize the compound with antitumor properties
...


Curiosity, creativity, openness, and skepticism are important in the progress of science
...

- Many scientists contributed to the explanation of the ozone hole
...

- Paul Crutzen: Meteorologist, Used mathematics to show destruction of the ozone was
possible
...


Ozone - molecule made of three oxygen atoms
...


All Matter is made up of matter
Both air and ozone is made up of oxygen atoms
...

Molecules are made up of atoms and absorb radiation in different ways and in different manners
...

Scientific information is based off of what was previously known
...

Change of the Atom model:
- Dalton: Matter is made of atoms
- Thomson: Atoms contain electrons
- Rutherford: The mass of an atom is concentrated in its center
...

- Schrodinger and others: Electrons exist in clouds of probability
...

Discovery of new form of carbon:
- Discovered by Kroto, Smalley, and Curl
- Called buckyball
- Led to new class of carbon compounds: fullerenes

Technology aids scientific progress
- New technology = New discoveries
- New tools = New observations possible
- Improvements in technology = New discoveries
- More precise tools = Better data
- More powerful tools = Faster, more detailed data analysis
- Scientific discoveries = New technologies
- New areeas of study
- New Substances
- Scientific discoveries = improved technologies
- Improvements in efficiency
- Reductions in negative effects
How does Scientific knowledge progress?
Qualities:
- Diversity
- Creativity
- Curiosity
- Openness
- Skepticism
Scientific Knowledge = Scientific Knowledge = Scientific Knowledge
Scientific Knowledge = Technology, Technology = Scientific Knowledge

The Nature and Processes of Science Page 3

Hypotheses, Laws, and Theories
Wednesday, October 21, 2015

12:54 PM

Difference between hypotheses, theories and laws:
- Hypotheses: Testable explanation of a scientific problem that is based on research and
observation
...

- Uses the if/then/because statement
- Must be testable through a scientific investigation
- Must be falsifiable (could be rejectable)
- Can be supported or refuted by data
- Theory: Well-supported, widely accepted explanation for many observations
...

- Can be used to predict events or experimental results
...

How scientists work with a Hypothesis:
- Make a hypothesis:
- Attempt to explain an observation or answer a question
...

- Support the hypothesis:
- See if data agree with the hypothesis
...

- New data lead to a new hypothesis
- Continue to evaluate as new data become available
...

- Mass of ashes < Mass of wood
- Test: Lavoisier headed mercury
...

Dalton's Atomic Theory:
- All matter is composed of atoms
- Atoms cannot be made or destroyed during chemical reactions
- All atoms of an element are identical
- Different elements have different kinds of atoms
- Chemical; reactions occur through rearrangements of atoms
...

The atomic Theory explains the law of conservation of mass
...

Evidence for the atomic theory:
- Development of a periodic table showing that different elements have different properties
- Chemical analysis showing that all atoms in starting material are found in products of reaction
...

Scientists share their research and ideas with others through talks and publication
...

Scientific hypothesis:
- Explanation based on existing knowledge
Scientific Law:
- Description of how systems behave under certain circumstances
- Does not explain why things happen
Scientific Theory:
- Well tested, widely accepted explanation for natural phenomena
...

- Reproducibility
- Reliability

The Nature and Processes of Science Page 5

Scientific Methods
Friday, October 23, 2015

11:40 AM

Scientific Method:
Scientific Inquiry The process of using observations and experiments to learn about natural events
...


Observation The act of using your sense to gather information
...

Qualitative

Subjective, not based on numbers

Quantitative Objective, based on numbers and measurements
...
because…
...

Data

Pieces of information obtained and recorded during an experiment
...


Conclusion The general summary of the results and what they mean
...

Sample conclusion:
The data supports the hypothesis
...
Therefore, we can conclude that dissolving salt in water increases the boiling
temperature of the water
...

The final step is to Communicate results
...

Control Sample

A sample in a controlled experiment with variables that do not change
...


Independent Variable Causes a change to another variable (X)

The Nature and Processes of Science Page 6

Dependent Variable

Is changed by another variable (Y)

Sample Question:
What is the effect of X (Independent) on Y (Dependent)?

Before scientists present their data, they have to analyze the results
...

Model

Help present experimental results

A Model can be:
- Sample
- Idea
- Picture
- Equation
- Method
- Diagram
Communicating Results:
A lab report includes:
- A question
- A hypothesis
- The materials needed for the experiment
- The experiment
- The experimental procedure
- An analysis of the results
- A conclusion
Peer Review An evaluation done by scientists on the work and conclusions of another scientist
...

- Large Setting
○ Conference
- Small Setting
○ Poster Session
What should you do before you begin to plan a scientific investigation?
- Perform background research to learn what is already known about the question you are trying to
answer
...

In case of an accident:
- Stay calm and tell your teacher
- Follow your teachers instructions
- Avoid dangers; leave if necessary
- Do not try to clean up a spill
- Help anyone who is injured
- Use emergency equipment if necessary

Injuries

Directions

Cuts from broken glassware Apply pressure
Chemical burns or irritation Flush are
Heartburns

Remove heat source and put out fire

Inhalation of toxic chemicals Get some fresh air
Chemicals in eyes

Use eye wash

Always tell the teacher if something happens because u a littl bitch
MSDS

Material Safety Data Sheet

Material Safety Data
sheet

A form that describes the properties of, safe handling of, and emergency
procedures for a substance

-

Identify the substance
Physical and chemicals properties
Fire and explosion hazards
Health hazard data
Reactivity information
Handling and other special precautions

The Nature and Processes of Science Page 8

Scientific Notation and significant figures
Tuesday, November 03, 2015

11:40 AM

Decimal Number "broken Down" into tens

Powers of ten Form

10

10

1 x 10^1

100

10 x 10

1 x 10^2

1000

10 x 10 x 10

1 x 10^3

10,000

10 x 10 x 10 x 10

1 x 10^4

100,000

10 x 10 x 10 x 10 x 10

1 x 10^5

1,000,000

10 x 10 x 10 x 10 x 10 x 10

1 x 10^6

1,000,000,000

10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 1 x 10^9

1

1

1 x 10^0

0
...
01

1 / (10 x 10)

1 x 10^-2

0
...
0001

1 / (10 x 10 x 10 x 10)

1 x 10^-4

0
...
000001

1 / (10 x 10 x 10 x 10 x 10 x 10)

1 x 10^-6

Scientific Notation A way of writing a value as the product of a number, n, between one and ten, and a power of ten, m; n x 10^m
24,000 => n = 2
...
4 x 10^4

Example:
0
...
7
- M = -5
- 9
...
000097 g
- 9
...
7 x 10^5 g
- -9
...
0
Metric Units
Prefix

Exponent Number

Mega-

10^6

1,000,000

Kilo-

10^3

1,000

Milli-

10^-3

0
...
000001

Nano-

10^-9

0
...
91 x 10^11 m
Write 0
...
0000914 L = 9
...
5 x 10^5 km in standard notation
The Nature and Processes of Science Page 9

Write 2
...

- Multiplying: multiply the two coefficients (numbers) and add the exponents
- Dividing: divide numbers by numbers and subtract exponents when dividing
...

Rules of Significant Figures:

1

ALL non-zero numbers are ALWAYS significant

2

ALL zeros between non-zero numbers are always significant

3

ALL zeros which are to the right of the decimal point and at the end of the number are always significant
...
4428 g = 6 significant figures
58
...
78
+ 6
...
5939

The Nature and Processes of Science Page 10

Dimensional Analysis
Wednesday, November 11, 2015

12:02 PM

Dimensional Analysis A system to convert units from one system of measurement to another
...

- Calculate the cost of pizzas:
○ 3 pizzas x $15/pizza = $45
○ Pizzas cancel each other out and you are left with $ as the unit of measurement
Dimensional
Analysis

A method applied in science that uses the relationships between quantities in
order to solve problems and determine appropriate units
...

Set up a single equation:
6 people x (4 slices / 1 person) x (1 pizza / 8 slices) x ($15 / 1 pizza)

Solve:
6 people x (4 slices / 1 person) x (1 pizza / 8 slices) x ($15 / 1 pizza)
- People cancel out
- Slices cancel out
- Pizza cancels out
- $'s are left
Equalities

How much of one unit is equal to another unit

Conversion Factors Fraction used to convert from one unit to another
...
00; 15 x 1 x 4 = 60; 240 / 60 = 4
...
5 kilometers?
2
...
5 km x (1000m / 1km) x (1,000mm / 1m) = 2
...
68 x 10^-25 kg
...
25 mg sucrose?

...
68 x 10^-25 kg) = 4
...


Dimensional Analysis can also be used in non-quantitative analysis:
- Units of a measurement can be determined without quantities (numbers)
- Set up a conversion exactly as if there were quantities
Dimensional Analysis is a way of combining multiple conversion equations into a single operation
...

- Operations carried out on unit are also applied to conversion factors (square, cube and so
forth)
You use Dimensional Analysis:
- Converting between units
- Calculating one quantity given another
- Determining units of a constant

The Nature and Processes of Science Page 12

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Lab
Friday, November 13, 2015

Mass

12:05 PM

The amount of matter in a substance

A balance

Grams,
kilograms

Volume The amount of space a substance takes up
...


Cm^3, milliliter,
Liters

Density Matter per unit of space
...

This uses Mass and volume
...
g/cm^3,
kg/L
...

Density is the same for any amount of the same material
...

Lab Question:
How do you measure the mass, volume and density of certain objects?
- Fluids in a graduated cylinder will form a meniscus
...

○ Remember that 1 cm^3 = 1 mL
Significant figures are the digits that are known for a measurement plus one estimated digit
...

- In science, the number of digits that you report conveys accuracy
...

How to significant figures"
- Addition and Subtraction: Round the result to match the measurement with the fewest decimal
places
...
4 cm + 4
...
2 cm
- Multiplication and Division: Count number of significant figures
...

- When matter undergoes a chemical change, its identity changes and so the matters original
properties are replaced by new properties
...
Does not depend on amount of material
...

Examples of Intensive: Temperature, Density
...

- Physical Changes occur when the physical properties indicate that the same substance exists
...

○ Burning Objects
○ Cooking / Baking
○ Running fuel engines
○ Biological processes
○ Fireworks

Matter^J Atomic Structure^J and the Periodic table Page 14

Elements, Compounds, and Mixtures
Tuesday, November 17, 2015

12:32 PM

Mixture A composition of two elements
...

Density - Physical Property
Flammability - Chemical Property
Solubility in water - Physical Property
Sodium Chloride Table Salt
Matter can be a pure substance or mixtures
...

Examples of a pure substance:
- Water
- Salt
Element A pure substance consisting of any one type of atom
...

- Atoms cannot be separated thru physical processes
...

Sodium + Chloride = Sodium Chloride
Na + Cl = NaCl
Nitrogen + Hydrogen (elements) = Ammonia (Compound) NH3
Examples of compounds:
- Water
- Salt
- Emerald
- Rust
Mixture Combination of two or more pure substances that are not chemically combined
- Can be separated thru physical means
...


Matter^J Atomic Structure^J and the Periodic table Page 15

Separation of Mixtures using physical methods:
- Sorting (Hand picking)
- Filtration (filtering)
Distillation Process in which a mixture is separated using the differences in boiling points of the
different components of the mixtures
...

Chromatography

-

Process in which a mixture is separated using differences in this ability of the
differences in the ability of the components of the mixture to pass thru a substance
...

Mixtures are either homogeneous or heterogeneous
Most materials are mixtures
...

Physical properties of pure substances are used to determine how to separate a mixture
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Matter^J Atomic Structure^J and the Periodic table Page 16

The Structure of the Atom
Tuesday, November 17, 2015

12:32 PM

• The smallest part of any substance is the atom
Particles of an Atom:
- Proton
- Neutron
- Electron
Atom

The smallest particle of an element that has the same properties as the element
...

 Sub atomic particles are found in these two locations
...

Electrons (-) A negatively charged particle in the orbitals surround the nucleus of the atom
...


 An atom can have any different combination of these particles
 A electrically neutral atom occurs when the amount of protons equals the amount of electrons
...

 Different elements equal particle count and arrangements
...

 Larger atoms have more electrons (more orbitals)
Atomic Mass unit The unit to express the mass of an atom
...
660538921x10-24g
Proton:
- Mass: 1
...
675x10^-24g
- Mass: 1 amu

Matter^J Atomic Structure^J and the Periodic table Page 17

Electron:
- Mass: 9
...
0006 amu
Quarks Are small particles that make up protons and neutrons
...

 Elements are made of sub atomic particles
 The properties of atoms are determined by the amount of each sub atomic particles
...

- Differs for each element that is equal to the amount of protons in the nucleus
...

○ Ass you go across the periodic table, the atomic number increases by 1
...

 The number of electrons of an atom, can't be used to identify the element
...

Ions

Atoms with charge

Anion

Negative Ion

Cation

Positive Ion

 When looking at the periodic table, you're looking at elements in the their elemental form, which
means that they are neutral
...

 When atoms are positively charged, they will have more protons than electrons
...

 Some elements are more likely to gain electrons as well as some are more likely to gain protons
...

Elemental Form Neutral Atom
Mass Number (A) The number of protons and neutrons in the nucleus of an atom
...

The mass number is the number of neutrons and protons, atoms with different atomic numbers are
different elements
...

Isotopes Atoms of the same element with different mass numbers
...

Atomic
Mass

The mass of a single atom; approximately equal to the total mass of the protons and
neutrons in an atom
...

- The weighted average atomic mass of aluminum is about 100% Al-27
...
That is why aluminum has an average atomic mass of 26
...
00
...
09
...
2297%

○ Si-29

4
...
0872%

How to calculate average atomic mass:
MA = (M1)(P1) + (M2)(P2) + … + (Mn)(Pn)
Ma

Weighted Average Atomic Mass of the Element

M1, M2,… Atomic Mass of isotope 1, isotope 2, …
P1, P2, … Fractional abundance of isotope 1, isotope 2, etc
Find the weighted average atomic mass of Chlorine isotopes:
- Cl-35, 34
...
78%
- Cl-37, 36
...
22%
Ma = (34
...
7578) + (36
...
2422) = 35
...
His work was based off of Joseph Proust
...

- The Law of Definite Proportions Small, whole numbers make up the ratio of the masses of the
elements found in a compound
...

Law of Definite proportions > Atomic Theory
These ideas are an explanation of the structure of matter in terms of different combinations of very
small particles
...
5 g oxygen or 27 g oxygen only
- Oxygen consumed in a 1:2 ratio
...
The atoms cannot
combine in any other ratios
...

○ Atoms of different elements are different
...

○ The ratio of atoms in a compound is fixed for all samples of the compound/
- A chemical reaction is a rearrangement of the atoms into new combinations
...
J
...

- Discovered Electron
- Concluded that particles must be part of an atom, and atoms must have subatomic particles
...

- Together, Millikan's and Thomson's results allowed for the determination of the mass and charge
of the electron
...

- Tiny positively charged particles shoot out of a particle gun toward a thin sheet of gold foil
...

Matter^J Atomic Structure^J and the Periodic table Page 21

- Reflected particles are detected at various angles
...

Summary:
- Dalton's Atomic Theory:
○ Based on evidence and observation
○ Atoms are indivisible
○ All atoms of an element are identical
○ Atoms of different elements are different
○ Atoms combine in fixed ratios to form compounds
○ Atoms cannot be created or destroyed, only rearranged
...

○ Rutherfords work showed that t he plum pudding model in inaccurate
 Most of the mass of the atom is concentrated in the nucleus
 Most of the atom is empty space

Matter^J Atomic Structure^J and the Periodic table Page 22

The Modern Atomic Theory
Tuesday, November 17, 2015

12:32 PM

Daltons Atomic Theory (1808):
- Elements are composed of extremely small, indivisible particles called atoms
- All atoms of an element are identical and are different from of any o there element
- Atoms combine in whole number ratios to form compounds
- Chemical reactions involve the separated, combination or rearrangement of atoms, but not the
creation or destruction of atoms
...


Neils Bohr (1915):
- Proposed that electrons travel around the nucleus in fixed paths
...

- Higher orbits have higher energies
...

Changing energy Levels:
- Electrons can absorb energy and transition to a higher energy level
...

- Each element has unique energy levels
...

- Electrons have a definite radius and momentum
...

The bohr concept was replaced by the electron cloud model
...

Light and Photoelectric Effect:
- Light has properties of both a wave and a particle
- The photoelectric effect demonstrates that light can behave as a particles
...

- The photoelectric effect suggests that the Rutherford nuclear model of the atom is not accurate
...


Matter^J Atomic Structure^J and the Periodic table Page 24

Atomic Numbers and Electron Configurations
Tuesday, November 17, 2015

12:33 PM

- Electron arrangements can be used to predict the reactivity of the atom
...

Quantum Number Possible Values
N

Nonzero positive integers (1,2,3,4,…)

L

Positive Integers between 0 and n - 1

M

Integers between -l and +l
...


Electron Sub
Shell

A set of orbitals with the same principle quantum number, n, and the same angular
momentum quantum number, L
...

Antoine Lavoisier (1789):
- Thought light was an element
- Thought heat was an element
- First Attempt at classifying elements
John Dobereiner (1829)
- Arranged elements with similar properties into groups
...

- Included blank spaces for elements not yet discovered
...

94 Naturally occurring elements
...

Period

Horizontal row on the periodic table

- Atomic number increases from left to right across the period
...

Group

Columns on the periodic table; known as families
...

- Typical Properties:
○ Silver In color
○ Soft (Can be cut with a knife)
○ Highly reactive with oxygen and water
Able to oxidize in air
Matter^J Atomic Structure^J and the Periodic table Page 26

○ Able to oxidize in air
- Easily lose an electron to form a +1 Cation
...

Halogen Group 17 or 7A Fluorine, Chlorine, Bromine, Iodine, Astatine, Ununseptium
- Typical Properties:
○ Highly reactive with metals
○ Toxic to organisms
○ Most occur as diatomic molecules
○ Reacts with metals to form salts
...

- Inert Gases (nonreactive)
- Typical Properties:
○ Odorless and tasteless
○ Nonreactive and nonflammable
○ Extremely low boiling points
○ Produce characteristic colors when excited electrically
Transition Metals Groups 3 - 12 or Group B
- Typical Properties:
○ Form colored compounds
○ May have unusual properties:
 Magnetism
 High Conductivity
Lanthanides Elements 57 to 71
Actinides

Elements 89 to 103

- Typical Properties:
○ Radioactivity
○ Unstable
○ Present in only trace amounts on Earth
...

The simples elements are hydrogen and helium
...

The "-->" in chemical equations means yield
...

Formula Equation:
3H2(G) + N2(G) -> 2NH3(G)
The #s in the front are the coefficients, these tell how many molecules of the compound (H2)
...

The Letter in the parentheses is the state of matter the reactant is in
...

- Catalysts are added above the arrow because they are not used up
...


Balanced Chemical Equations:
- Have the same types atoms on both sides of equations
...

- Show conservation of mass
...


Decomposition

One chemical species breaks down to simpler elements / compounds
...


Double Replacement

Involves two ionic compounds (in solutions) that trade cations, creating two
new compounds
...


Oxide

A chemical compound that contains at least one oxygen atom and one other
element in its chemical formula
...
02 x 1023

Avogadro's
Number

The number of units in a mole, 6
...

Finding the molar mass of compounds:
- Identify the component elements and their average atomic masses
- Identify the number of atoms of each element in one unit
...

- Convert from atomic mass units to grams per mole
...

Empirical Formula The simplest whole-number ratio of atoms in a molecule or formula
...


• Which step would help a student find the molecular formula of a compound from the empirical
formula?
○ Multiply the ratio of the actual mass of the compound to the empirical formula mass by the
subscripts of the empirical formula
...
How can he check his result?
○ By adding them together and seeing if they total to 100
...

Kinetic-Molecular Theory:
- Gases are made up of a large number of hard spheres that are in continuous, random motion
...

- There is no force of attraction or repulsion between gas particles (+ & - Don’t attract / Repel)
- All collisions between particles are perfectly elastic
Kinetic energy Energy resulting from the motion of particles
- The average kinetic energy of the particles depends only on temperature
...

All Gases are compressible
- Significant volume change with increased pressure
No Fixed shape or volume
- Expand to fill container
When compressing gases, particles come closer together, increasing pressure
Lack of interaction allows particles to spread apart
Direct Relationship:
- As number of moles increases, so does the volume
- When temperature increases, so does pressure
- When temperature increases, so does volume
Diffusio
n

The spread of particles thru random motion from regions of high concentration to regions of
low concentration

Effusion The movement of a gas thru a small opening into a larger volume

Grahams Law: Rate of effusion is inversely proportional to the square root of molecular molar mass
Kinetic-Molcular Theory: Temperature is related only to average kinetic energy
...

- Gases expand to fill a container because there are no intermolecular forces holding their particles
together
- Pressure is the result of collisions of gas particles with a surface
...


The Kinetic Molecular Theory and States of Matter Page 35

Liquids
Wednesday, January 06, 2016

1:30 PM

Miscible
Liquids

Liquids that mix together completely and become a heterogeneous mixture
...


Surfactants

A substance that tends to reduce the surface tension of a liquid in which it is dissolved
...


Boiling Point

The temperature where the vapor pressure of the liquid is equal to the external
pressure on the liquid

• Liquids have enough energy to stretch the pulls of attraction but just not as well as gas
...

Intermolecular Forces:
• Effects interactions between particles
• Stronger forces require more energy to overcome liquid state
...

• Evaporation: Kinetic energy > Intermolecular forces
...

• Compounds with stronger forces have higher boiling points
...

Liquid Forces:
• Constant, random motion
Solid Forces:
• Fixed in place, vibrating
Freezing:
• Kinetic Energy > Intermolecular forces
...

Surface Tension:
• Directly correlated to intermolecular attraction
• Surfactant: Can reduce surface tension
...

• Dissolve: when a solid, liquid or gas becomes integrated into a host liquid
...


The Kinetic Molecular Theory and States of Matter Page 37

Solids & Plasmas
Wednesday, January 06, 2016

1:30 PM

The Kinetic Molecular Theory and States of Matter Page 38

Phase Changes
Wednesday, January 06, 2016

1:30 PM

Deposition When gas turns into a solid
• When a substance freezes, it is releasing heat energy
...


The Kinetic Molecular Theory and States of Matter Page 39



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