Ch. 1—Chemistry: An Introduction What is chemistry?

• Chemistry is the study of the ___________________ of substances and the changes they undergo.

• It began from “_______________”... the attempts of alchemists to change common metals into _________ through trial and error.

Divisions of Chemistry

There are several divisions or branches of chemistry:

1) _________ chemistry: the study of substances that contain ________

Example: how gasoline is produced from oil

2) _______________ chemistry: the study of substances __________ ___________

Example: how table salt reacts with different acids

composition

alchemygold

Organic carbon

Inorganic withoutcarbon

Divisions of Chemistry (continued)

3) _______________ chemistry: the study of the _______________ composition of substances

Example: how much chlorine is in a sample of tap water

4) ____________________: the study of the chemistry of _________ __________________

Example: how sugar in the blood stream of cats affect insulin production

Analytical quantitative

Biochemistry livingorganisms

Chemistry and Biology

Chemistry and Biology

Chemistry and Biology

Chemistry and Biology

Chemistry and Biology

Chemistry and Biology

Chemistry and Biology

The Scientific Method

• The scientific method is way to solve a scientific problem. It is an approach to a solution (using mostly common sense.)

Example: Your flashlight doesn’t work. (Not necessarily a “scientific problem.”)

Steps to the Scientific Method

(1) Make _________________-- Use your 5 senses to gather information.

(2) Propose a ______________-- Make an “educated guess” for what is happening.

(3) Perform _______________-- This tests your hypothesis. Many experiments are sometimes needed to test a hypothesis. The same experiment must give similar results if the experiment is to be reliable.

observations

hypothesis

experiments

Steps to the Scientific Method (continued)

(4) Make a _____________-- This should explain the results of your experiments. Theories may ___________ or be ___________ over time because of results from new experiments.

Scientific Laws

• Laws describe ____________ ___________________.

• A law tells what happens. It does not attempt to explain _____ the phenomena occurs. (That is the job of a theory.)

• Laws can often be summarized by a _____________ __________.

Example: PV = nRT (The “_________ ______ ______”) This equation is used in Ch. 12. The law

shows the relationship between the pressure, volume and temperature of a given quantity of gas in a container.

theorychange

natural phenomena

rejected

why

math equation

Ideal Gas Law

Chapter 2--Matter & ChangeMatter vs. Mass

• Matter is anything that has _________ and takes up ___________.

Examples: ________, __________, and ________... (the three phases of matter)

• Things that are NOT matter: __________, heat, ________, sound...

• Mass is the amount of ___________ in an object.

• The standard metric unit for mass is the ______________.

mass space

solids liquids gases

light emotions

matter

kilogram

States of Matter

phase fixed shape fixed volume compressible

solid

liquid

gas

Particle Motion

• Solids-- particles ____________ back and forth in fixed positions

• Liquids-- clumps of particles ______ past each other in the container

• Gases-- individual particles _____ all over the place and collide

• _________ is a term used for a gaseous substance that is normally a ________ or _______ at room temperature.)

Example: _______ vapor

YES

NO

YES

YES

NO NO

NO

NO

YES

vibrate

slide

fly

Vaporsolid liquid

water

States of Matter

Plasma

• Plasma is a high energy electrically charged mixture of ions and electrons. __________ are made of plasma.

• While plasma is the most abundant phase of matter in the universe, on earth it only occurs in a few limited places:

– Lightning bolts

– Flames

– Fluorescent lights

– Aurora Borealis (Northern Lights)

Stars

Bose-Einstein Condensate• Predicted in 1924 and created in 1995, the BEC is a small group of

atoms clumped together when taken down to a few billionths of a degree above absolute zero.

• This group of atoms takes up the same place, creating a "super atom." There are no longer thousands of separate atoms.

• They all take on the same qualities and for our purposes become one blob.

Einstein Bose

400 nanoKelvins 200 nK 50 nK http://www.colorado.edu/physics/2000/bec/

Physical Properties and Physical Changes

• Physical properties can be determined/measured without changing the substance’s composition.

Examples: _______, odor, __________, mass, ________, _________ point, ____________ point, hardness,

solubility, etc.

• Physical Changes alter a substance without changing its composition.

Examples: crushing, ripping, breaking, and any _________ changes…(boiling, freezing, melting, etc.)

• Most physical changes just alter the size of the particles and are usually reversible.

tastecolor densitymeltingboiling

phase

Physical Properties

Physical Changes: Names of the Phase Changes

Solid

LiquidGas

SolidAqueous = ___________ Aqueous Solid = ___________dissolving crystallizing

Mixtures• Mixtures are a physical blend of two or more substances mixed

together.” The parts can be separated by _____________ means or ____________ changes.

There are 2 types of mixtures:

(1) _________________ Mixtures: the parts mixed together can still be distinguished from one another...NOT uniform in

composition.

Examples: chicken soup, fruit salad, _____, sand in water

(2) _________________ Mixtures: the parts mixed together cannot be distinguished from one another...completely uniform in

composition.

Examples: ______, Kool-aid, ________, salt water, milk

• Another term for a homogeneous mixture is a “______________.”

physicalphysical

Heterogeneous

Homogeneous

dirt

Air Brass

solution

Heterogeneous Mixtures

Homogeneous Mixtures

Distillation• One way to separate a _________ from a ___________ in a

solution is by distillation. There are 2 steps to the process:

Step 1: _________ the solution.

Step 2: ________________ the vapor as is escapes and collect it.

Distillation Animation

solid liquid

Boil

Condense

Chemical Properties and Chemical Changes• Chemical properties cannot be determined/measured without

changing the substance’s composition

Examples: ____________, whether or not it reacts with an acid or a base.

Chemical Changes

• Chemical changes will alter a substance and change its composition.

Examples: burning, ___________, rotting or decomposing, __________________, and other chemical

reactions.

• Most, but not all, chemical changes are irreversible.

– You can’t “reverse” the burning of paper.

– _____________ ____________ use a reversible chemical reaction

burning

rustingfermenting

Rechargeable batteries

1) ________ is produced: (________)

2) ________ is produced: (_____________ bugs/_____________)

3) ______________ is produced:

(______________)

Indications of Chemical Reactions

lightning fireflies

matchesHeat

Light

Electricity

batteries

Indications of Chemical Reactions4) ___________________ forms: (_______ ________)

5) gas/smoke/odor/bubbles produced:

(________ ______)

Two liquids chemically react to form a solid.

soap scumPrecipitate

soda fizz

Elements vs. Compounds• An element cannot be ___________ down or _____________ into

simpler substances by chemical means.

• Elements are the _________ forms of matter that can exists in normal laboratory conditions.

Examples: _______, Helium, __________

• A compound is made up of ____ or ________ different elements ______________ bonded together.

• Compounds can only be broken down into simpler substances by ____________ ____________.

Examples: _______, Sand, _______________

broken changed

simplest

MercuryGold

2 morechemically

chemical reactions

Water NaCl (table salt)

Classification of Matter

Classification of Matter

Classification of Matter

Chemical Symbols• Chemists use chemical symbols for the elements involved in a

chemical reaction. The symbols are a shorthand way of representing the ______________. (See the Periodic Table for a list of all the symbols.)

• The first letter of the chemical symbol for an element is always _________________.

• The next letter, if needed, is _______________. Each capital letter in a formula, therefore, represents another element.

Examples: ____, ____, Hg, ___, NaBr, ________, LiC2H3O2

• Some symbols come from _______ names: Au=Aurum (Gold)

elements

capitalized

lowercase

H Ne S

Latin

H2O

Chemical Reactions• When writing chemical reactions, the substances that ___________

with each other are written on the _______ and are called “reactants”.

• The substances that are ____________ are written on the _______ and are called the “products.”

Reactants Products

• The “ ” symbol can be read as “_______” or “reacts to produce.”

Example: 2H2 + O2 2H2O

which means “____________________________________

________________________________________________.”

reactleft

produced right

yields

two hydrogen molecules plus one oxygen

molecule yields two water molecules

Conservation of Mass• During chemical (or physical) reactions, mass (or matter) is neither

_____________ nor _________________.

• The mass of all the reactants _________ the mass of all the products.

• The ___________ of each kind of atom is the same.

• Sometimes it appears that the reactant and product masses are not equal, but a _______ was probably a reactant or product in the reaction, and that is making the difference!

Example: 2H2 + O2 2H2O

• If 4 grams of hydrogen reacted with oxygen to produce 36 grams of water, how many grams of oxygen were used? _______

• Notice that the ____ of H’s and O’s on each side is __________!

created destroyed

equals

number

gas

32

# constant

Conservation of Mass

CaCl2 + Na2SO4 CaSO4 + 2NaCl

mass before = mass after

# atoms before = # atoms after