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
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
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 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
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)
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