Other things you may want to remember....
dependent
or independent varible
speed
needs distance and time
speed
= dependent
distance
= independent
time
= independent
To
put it more simpily dependent HAS to have 2 or more independent values; you can not get something with
out the independent value; then the dependent value would not exist!
Types of Graphs
Line Graph = to show change
over time.
Bar Graph = to show comparisons
Circle Graph = to show
percentages
4 Basic States of Matter
Solid =Molecules are tightly
packed together. Solids have a definite shape and a definite volume.
Liquid = definite volume, no definite
shape [Takes the shape of its container]
Gas = No definite shape or volume
Plasma = SUPER HEATED, charged particle
: the most prevalent state of matter in the universe, such as the sun and lightning
The Atom Propertys
Atomic Mass = #
of protons and # nuetrons
Atomic Numbrer = # of electrons
and # of protons
Valence electrons = the
number of electrons there are in the outermost level.
ION?
Positive ion = is when an atom has lost 1 or
more electrons
Negative ion = is when an atom has
gained 1 or more electrons
information you can
get from a chemical equation
-
Elements involved
-
reactants and products
-
The amounts of each element in the reaction
-
Type of reaction
How to write a biconditional statement
- the positive ion is writen
1st
- the negitive ion is writen
2nd
- the positive ion
keeps its full name
- while the negitive ion has
the first part of its name and has -ide added to the end of it
What is a subscript and
how in the world am I suposed to do one?
- lets say you wish to combine Be which is Berillium
and is in group #2
- and combine it with N being Nitrogen whichis in group
#15
- using the oxidation numbers we find out first which element
goes 1st
- Group # 2 has an oxidation number of 2+
- Group #15 has an oxidation number of 3-
- There for group #2 would be written 1st and group
#15 would be written 2nd.
- (Be+2) (N 3-)
- x
- cross these and you get
- Be3N2
- the subscrpt tells you the amount of atoms of each element is combined
in the compound
Atomic Mass Unit = AMU
Avogadros number = 6.02 *10 to the 23rd power
Physical
or Chemical
-
Physical
change is a change in size, shape, color, state, Matter.
-
Chemical
change is when a new substance is formed
Steps
for balancing chemical Equations
Step
1. Use the correct formulas. Check the formulas of the reactants and products.
Step 2. Determine if the equation is balanced. Count the number of atoms of each element
on the reactant side and the product side. Count a polyatomic ion as a group if its formula is unchanged.
Step 3. Balance the equation one element at a time. Pick an element, and balance
the equation for that element by placing coefficients in front of the formulas to equal the number of one both sides of the
arrow. A typical starting place is with a formula that has subscripts. Never try to balance an equation by changing the subscripts
of a formula- that would make the formula incorrect. Balance diatomic elements last.
Step 4. Check to see if the equation is balanced. Sometimes balancing one element will
put another element out of balance. If that happens, repeat steps 3 and 4 until the equation is balanced. Make sure the coefficients
you use are the smallest possible whole numbers. If you can divide all the coefficients you use are the smallest possible
whole numbers. If you can divide all the coefficients by 2 or some other number, do so to make them small as possible.
Things you must know in order to read a chemical equation
R ---> P
R = reactant, ----> = yields , P
=Product
-
Reactants : the compounds or elements involved the reaction
-
Products : the new substances that are formed
-
Limited reactant = is used up first.
-
Excess Reactant is not fully used up.
-
Percent yield = the actual yield [what you really got] divided
by the Predicted yield [what you expected to get].
Classifying chemical reactions
- Synthesis
- two or more substances join to form one product
A + B 
AB
- Decomposition
- One reactant breaks down to form two or more products
AB A + B
- Single Displacement
- One element replaces another in a compound
A + BC -> AC + B
D + BC -> BD + C
- Double Displacement
- two compounds react to form two different compounds
- The positive part of the 1st compound combines with the negative part of the second compound (They swap partners)
- A precipitate, water or gas is produced when two ionic compounds combine
- Combustion
o ->CO2+ H2O
Endothermic [->] Exothermic
if energy is required to start a reactant
it is endothermic
Energy [->] a+b
if energy is produced from the reactant it
is exotherimic
a+b [<-] Energy
Acid & Bases
-
On a personal level - acids & bases help digest our food
-
In your mouth saliva is a slight acid it is there to break down foods chemical compounds
-
In your stomic - Hcl (hydrochloric acid) breaks down food farther -very strong
acid- currosive
-
Bicarbonate in pancreas neutralizes HCl. bicarbonate
is a base.
[Ph]
(N < 7) = [Acid]
(N =
7) = [Neutral]
(N > 7) = [Base]
Acid Rain Ph range of (3-5.5) range
Acid - chemical that contributes
H+ to a solution.
if you see H by itself more than likely its an acid
A Base Chemical that
contributes OH- to a solution.
if you see OH its more than likely to be a base
A netrual compund would be a...
Salt contains neither (H+)
or (OH-)
