Ch. 1-- How to Study Chemistry 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 5 major 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) _____________ chemistry: the study of the theories and ________________ behind the behavior of chemicals at the ___________ scale

Example: how the size of a water molecule determines the rate at which it dissolves table salt

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

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

(Obviously, these divisions will often overlap.)

Analytical quantitative

Physicalmathematicsatomic

Biochemistry livingorganisms

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 ____________ ___________________.

• They do not attempt to explain _____ the phenomena occurred. (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

The SI System (The Metric System)

• Here is a list of common units of measure used in science:

Standard Metric Unit Quantity Measured

kilogram, (gram) ______________

meter ______________

cubic meter, (liter) ______________

seconds ______________

Kelvin, (˚Celsius) ______________

• The following are common approximations used to convert from our English system of units to the metric system:

1 m ≈ _________ 1 kg ≈ _______ 1 L ≈ 1.06 quarts

1.609 km ≈ 1 mile 1 gram ≈ ______________________

1mL ≈ _____________ volume 1mm ≈ thickness of a _______

mass

length

volume

timetemperature

1 yard

sugar cube’s

2.2 lbs.

mass of a small paper clip

dime

The SI System (The Metric System)

Metric Conversions• The metric system prefixes are based on factors of _______.

Here is a list of the common prefixes used in chemistry:

kilo- hecto- deka- deci- centi- milli-

• The box in the middle represents the standard unit of measure such as grams, liters, or meters.

• Moving from one prefix to another involves a factor of 10.

*Example: 1000 millimeters = 100 ____ = 10 _____ = 1 _____

• The prefixes are abbreviated as follows:

k h da g, L, m d c m

*Examples of measurements: 5 km 2 dL 27 dag 3 m 45 mm

grams Liters meters

mass

cm dm m

Metric Conversions

• To convert from one prefix to another, simply count how many places you move on the scale above, and that is the same # of places the decimal point will move in the same direction.

Practice Problems:

380 km = ______________m 1.45 mm = _________m

461 mL = ____________dL 0.4 cg = ____________ dag

0.26 g =_____________ mg 230,000 m = _______km

Other Metric Equivalents

1 mL = 1 cm3 1 L = 1 dm3

For water only:

1 L = 1 dm3 = 1 kg of water or 1 mL = 1 cm3 = 1 g of water

Practice Problems:

(1) How many liters of water are there in 300 cm3 ? ___________

(2) How many kg of water are there in 500 dL? _____________

380,000

4.61260

0.001450.0004

230

0.3 L50 kg

Metric Volume: Cubic Meter (m3)

10 cm x 10 cm x 10 cm = Liter

grams Liters meters

Area and Volume Conversions

• If you see an exponent in the unit, that means when converting you will move the decimal point that many times more on the metric conversion scale.

*Examples: cm2 to m2 ......move ___________ as many places

m3 to km3 ......move _____ times as many places

Practice Problems: 380 km2 = _________________m2

4.61 mm3 = _______________cm3

k h da g, L, m d c m

twice

3

380,000,000

0.00461

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

Chapter 2--Matter & Change

Physical Properties

Physical Changes: Names of the Phase Changes

Solid

LiquidGas

SolidAqueous = ___________ Aqueous Solid = ___________dissolving crystallizing

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.

www.edumedia-sciences.com/a438_l2-distillation.html

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

Matter 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

• There are 3 states (or phases) of matter.

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

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

Elements vs. Compounds• Elements are the _________ forms of matter that can exist in

normal laboratory conditions.

• An element cannot be ___________ down or _____________ into simpler substances by chemical means.

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