Unit #2

Intro to Chemistry, Branches of Chemistry,

Scientific Method, & Matter.

Alchemy-

Ancient practice in which the "scientist" attempted to turn common metals into gold.

WE KNOW THIS IS IMPOSSIBLE, but they did not. However, they did help science in that they discovered chemicals, designed lab equipment, and even "discovered" how to separate mixtures by distillation and sublimation.

Chemistry-

The study of the composition of substances and the changes they undergo.

Antoine Lavoiser-

"Father" of modern chemistry.

He made and recorded changes of mass during chemical reactions.

Chemistry is all around us. You live with it and its products on a daily basis.

Can you think of any examples?

Synthetic fibers -Nylon, Rayon, Spandex, Polyester…Clothing dyesHair coloringNail polish removerSoaps

Calculators, iPods, Cell phones…Crude oil and its derivatives.Many others…

Major Branches (types) of Chemistry

Organic Chemistry- The study of essentially all substances containingcarbon; deals with the "SPONCH" elements.

SPONCH- an acronym made of the element symbols of: Sulfur, Phosphorus, Oxygen, Nitrogen, Carbon, & Hydrogen.Often used by: Chemical engineers (creators of tire compounds, insecticides, synthetic lubricants…), Lab technicians, Medicine inventors…

Organic Chemistry (con’t) -

Synthetic fibersNon-stick cooking surfaces

(Teflon)Tires…

Examples:

Physical Chemistry- The study of chemicals and the

changes in energy as they undergo reactions and processes.Examples: Balloons

Automobile engineersExplosive designers

Energy = 1. work, 2. heat, 3. entropy (vibration and wasted energy (disorder)).

Inorganic Chemistry- The study of substances without

carbon; mainly from non-living things.

Examples: MineralsGemologyMetal manufacturingAlloys

Generally anything not “SPONCH”

Analytical Chemistry- Concerned with the composition of

substances. There are two types: Qualitative and Quantitative.

Examples: Soil testingWater testingBlood analysis.

Qualitative Analytical Chemistry -Determines if a substance is present by

testing for its characteristic reactions with certain substances.

Examples: Test for Lead paintTests for “banned” substancesIndicates only the presence of something

Quantitative Analytical Chemistry -Determines how much of a substance is

present; its quantity; ("Percent composition").

Examples: Blood Alcohol TestTesting for Sugar in diabetic bloodTesting for pH in swimming pools

Biochemistry- The study of the chemistry of living

things and their processes.Examples: Photosynthesis

RespirationMarine biologyDigestionWMD(Biological or chemical weapons)

Some other Natural Sciences that involve Chemistry:

1) Geology:The study of the earth.

Petroleum, distillation of crude oil, mining and how much sulfur may be in the coal.

Examples:

Some other Natural Sciences that involve Chemistry (con’t):

2) Biology: The study of the life.

How body processes function, detoxification of poisons (including

medicines), respiration, and photosynthesis.

Examples:

Some other Natural Sciences that involve Chemistry (con’t):

3) Physics:The study of energy and forces.

Electronics, circuit boards, computer chips, diodes…

Examples:

Two types of Chemistry -

1) Pure Chemistry

2) Applied Chemistry

Pure Chemistry- Knowledge is accumulated for

its own sake; neither good nor bad.

Examples:

Chemical reactions, how much, what is it, color?, texture…

Applied Chemistry- Knowledge is either used to

benefit or harm people or the environment.

Examples:Medicine, chemical warfare, cloning.

The Scientific Method -

A series of steps used to solve problems.

5 steps of the Scientific Method:1) Observe the problem.

“What’s wrong?”

5 steps of the Scientific Method (con’t):

2) Hypothesize the reason.Ask questions to find out why there is a problem.

5 steps of the Scientific Method (con’t):

3) ExperimentTo test your hypothesis.

5 steps of the Scientific Method (con’t):

4) AnalyzeDid the experiment prove your hypothesis correct?

If not… go back to the hypothesis step.

5 steps of the Scientific Method (con’t):

5) Conclude / TheorizeConclude why the problem occurred.

Theory vs. Law

Theory- A thoroughly tested

explanation of why experiments give certain results.

Law- A concise statement that

summarizes the results of a broad spectrum of observations and experiments.

What is the difference between a theory and a law?

A theory explains why experiments give results. A law describes the results of observations.

Matter

Matter -Anything that takes up space and has a mass.

Mass -Amount of matter in an object.

Weight -Effect of gravity on matter.

What is the difference between mass and weight?

Assume a jar of peanut butter weighs 600 g. (1.32 pound) on earth. The moon's gravity is 1/6th that of the earth's; therefore the same jar would weigh only 100 g. (0.22 pound) on the moon. That is weight. However, did the mass change ? (Assume it was never opened.) No. That is mass (the amount of matter).

All matter belongsto one of two groups of matter:

1) Heterogeneous matter2) Homogeneous matter

Heterogeneous matter- Matter that is different or not

uniform in composition; each type of substance retains its own unique properties, and each can be separated from the other by ordinary chemical means. These are all mixtures.

Examples of Heterogeneous Matter:

M&MsTossed saladLucky CharmsJell-O fruit salad…

Homogeneous matter- Matter that is uniform in

composition.

Examples of Homogeneous Matter:OxygenWatersalt waterkool-aidAluminum

IronCarbon dioxidetomato soupJuice

These may be either mixtures (specifically solutions) or pure substances.

Mixtures -A general type of matter

that may be either heterogeneous or homogeneous. (They are a physical blend of two or more substances.)

All homogeneous matter belongs to one of two groups:

1) Pure substances2) Solutions

Pure substances- A particular kind of matter with

a definite and uniform composition.Examples: Water

CO2

OxygenLeadAmericium

Solutions- Homogeneous mixtures.

Examples: Salt waterOrange juice…

Solutions have phases that are either solid, liquid, gas, or a combination of the three.

They are always listed with the lesser constituent first.

All solutions are a mixture of the solute and solvent.

Solute- The substance that is dissolved. It is the lesser constituent by volume.

Example: The “Salt” in saltwater.

Solvent- The substance that does the

dissolving. It is the greater constituent by volume. Example: The water in saltwater.

There are 6 types of solutions based on the phases of their components.

Remember: The components are always listed with the solute first, followed by the solvent.

1) Gas - GasExamples: Oxygen in the air.

Recall the composition of “Air”NitrogenOxygenCarbon dioxideArgon and all others.

75%20%4%1%

100% Air

2) Liquid - GasExamples: Water vapor in the air.

3) Gas - LiquidExamples: Carbon dioxide in water.

4) Liquid - LiquidExamples: “2 - Stroke Fuel” (Oil in Gas).

5) Solid - LiquidExamples:Sugar / flavoring in water (“Kool-aid”)

6) Solid - SolidExamples:Alloys:

1. (Copper in Silver, “Sterling Silver”)2.

A homogeneous solution has only one phase (“Kool-aid”), while a heterogeneous solution has 2 or more phases. (Vinegar & Oil).

All pure substances belong to one of two groups:

1) Elements2) Compounds

Elements -

A substance that cannot be decomposed by ordinary physical or chemical means, under normal laboratory conditions. Each has its own unique and identifiable characteristics.

Examples: Anything on the periodic table.

Compound -

Examples: NaCl, H20, CO2

A chemical combination of elements. Each has its own unique and identifiable characteristics. Cannot be separated by physical means. Can be separated by chemical means.

There are two main groups of elements:

1) Metals2) Non-metals

Metals- Elements that are usually solid /

liquid at room temperature, good conductors of heat and electricity, malleable, ductile, often shiny (luster).Examples: Magnesium

SodiumIron

Non-metals - Elements that may be either

solid, liquid, or gaseous, poor conductors of heat and electricity, brittle, and often dull.Examples: Argon

SulfurIodine

Two specific types of non-metals are:

1) Metalloids2) Gases

Metalloids- Non-metals with some metal like

properties.Often used in electronics.

Examples: SiliconArsenicBoron

Gases - Elements that are "gases". They

are matter with no definite shape or volume, are fluid (they "flow").

Examples: OxygenHeliumRadon

Compound -Remember-

A compound is a chemical combination of elements. Each with its own unique and identifiable characteristics. They cannot be separated by physical means, but can be separated by chemical means.

Another example:

Na is explosive when wet

Cl2 is a poisonous gas.

When combined, they produce the compound known as Sodium chloride ("table salt”).

Law of Definite Composition-

All compounds have a definite composition by mass.

Example:Water has a mass of 18g. / mole.

Of those 18 grams, 11.1% are always from the Hydrogen.The remaining 88.9% are from the Oxygen.

Matter

Heterogeneous Homogeneous

Solutions Pure substances

Mixtures

Compounds Elements

Metals Non-metals Others

Physical property- A quality or condition of a substance that can be observed or measured without changing its composition. The value does not change with the amount of substance.

Examples:1) Density2) Boiling / Condensation point3) Melting / Freezing point4) Color5) State6) Odor7) Texture8) Solubility9) Hardness

Chemical property- The ability of a substance to

undergo a chemical reaction (a change) and form a new substance with new, unique properties.

Physical change-

Altering a substance without changing its composition, physical or chemical properties.Examples: Grinding

Melting / Freezing / BoilingChopping…

Chemical change- Alters a substance by changing its

composition.

Examples:Combustion of hydrogen to produce waterOxidation of iron to make "rust"Decomposition of carbonic acid to make waterand CO2.

The States of Matter.

Identify each drawing below as either a gas, liquid, or a solid.

Solid Liquid Gas

Solid- Matter with a definite shape

and volume. (Low energy and entropy).

Liquid- Matter without a definite

shape, has a definite volume, "flows", takes the shape of the container as it fills it from the bottom up. ("Moderate" energy & entropy).

Gas- Matter without a definite

shape or volume. (High energy & entropy).

Fluid- Any matter that flows.

Includes both liquids and gases.

Liquid- Matter without a definite

shape, but with a definite volume. Does not include gases.

Fluid Liquid

Vapor- Describes a substance that although it is in

a gaseous state (like a gas), is either a liquid or a solid at room temperature.

Examples: Steam

Sodium vapor in street lightsXenon vapor in HID headlamps,

Gasoline vapor in an internal combustion engine.

Gas- Matter without a definite

shape or volume. (High energy & entropy).Examples: Oxygen

HeliumRadon

Gas Vapor

Processes in nature are driven two ways:

1) Toward lowest energy.2) Toward greatest entropy.

Entropy -The amount of disorder in a system.

Increasing Entropy & Energy Warming

Decreasing Entropy & Energy Cooling

Melting

Freezing

Evaporating

Condensation

Solid

Gas

Liquid