Chapter 5

-Chemical change-> reacting substances change into new substances w/different forumulas & properties. Properties may include color, bubbles, or solid.

-Physical change-> appearence has changed. ie solid to liquid to gas

-Balancing Equations
*atoms cannot be lost or added
*same number of atoms for each element on both sides
Ex. CH4 + O2 --> CO2 + H2O
CH4 + O2 --> CO2 ++ 2(H2O)
CH4 +2(O2) --> CO2 + 2(H2O)

-Meaning of symbols
+-seperates two or move formulas
-->-reacts to from products
triangle- reactants are heated or heat
(s)-solid
(l)-liquid
(g)-gas
(aq)-aqueous

-Types of Reactions
*Combination->two or more elements bond to form one product
Ex. S(s) + O2(g) --> SO2(g)
*Decomposition-elements in a compound are replaced by other elements
Ex. [single replacement] A +BC --> AC + B
*Combustion- fuel and oxygen are required. CAn produce CO2,H2O,or heat.
Ex.CH4(g) + 2(O2)(g) --> CO2(g) + 2(H2O) + heat

-Oxidation -> loss and gain among reactants
*in every oxidation-reduction, the number of electrons exchanged must be equal ie. 2 loss and 2 gained. not 2 loss and 1 gained.
*The loss of electrons is an Oxidation. That element got oxidized.
*The gain of electrons is called Reduction. That element was reduced.
Ex. Ca + S -->Ca2+ + S2- which makes the compound CaS

Rule of thumb: a) The first element in a compound is positive, and second is negative.
Ex. CuO. The Cu is positively charged and the O negatively.
b)You can tell whether an element was either oxidized or reduced by the position (ie. first or second
Ex. Zn + CuSO4 --> ZnSo4 +Cu
The Zinc was oxidized because it was nuetral and lost electrons. It was made positive as a result.
The Copper was positive, but took two electrons and balanced out
The Sulfur Oxide ion did not change

-Mole -> 1 mole contains 6.02 x 10^23 atoms (or formula units). Also known as Avagadro's Number
Ex. 1 mole of H = 6.02 x 10^23 atoms
1 mole of CO2 = 6.02 x 10^23 molecules of the carbon dioxide
*In a compound, the number of atoms is also the number of moles
Ex. #1 H2O. 2 moles of H and 1 mole of O

Ex. #2 How many moles of S are in 3 atoms of Al2(SO4)3?
3 mole Al2(SO4)3 x 3 moles S/1 mole Al2(SO4)3 = 9 moles of S in 3 moles of Al2(SO4)3

Ex. #3How many moles of Al are in 0.40 moles of Al2(SO4)3?
0.40 mole Al2(SO4)3 x 2 moles Al/ 1 mole Al2(SO4)3 = .8 moles of Al in 0.40 mole os Al2(SO4)3

-Molar Mass
*use atomic mass to determine molar mass
*atomic mass/ 1 mole
Ex. 0.750 mole Ag x 107.9 g Ag/ 1 mole Ag = 80.9 g Ag

-Mole to mole relationship in Equations
2Fe + 3S = Fe2S3

Ex. #1 How many mole of Fe would be produced if reacted with 3.6 moles of S?
3.6 mole S x 2 mole Fe/3 mole S = 2.4 mole Fe

Ex. #2 How many grams of Fe produced with 8 moles of S?
8 mole S x 2 mole Fe/3 mole S x 55.85 g Fe/1 mole Fe = 297.87 g Fe.

Chapter 8

-Mixture that is charged by ions, whose particles can pass through filters

Solvent -> substance in which the solute dissolve. or liquid
Solute -> the particles that dissolve
*To dissolve in solvent, the ions in solute are attracted to opposite ions in solvent
Ex. (salt) NaCl + H2O (water)
--Na+ is pulled by O-
--Cl- is pulled by H+, thus the salt dissolves
Note: If a substance does not dissolve, then it is not polar.
Non-polar solutes need non-polar solvent to dissolve

-In most solids, as temp in solvent increases, the amount of solute dissolves

-In gases, if temp is raised, the less soluable
*as temp increases, gas leaves solvent

-Electrolytes -> solutions containing ions (+ or -)
Strong electrolytes -> conduct well
Weak electrolytes -> conduct poor
non-electrolyte covalent compounds that don't conduct at all

-Molarity = mole/L = M
Ex.#1 What is the molarity of 60 g NaOH in 0.250 L of solution?
Hint:find moles first
69 g NaOH x 1 mole/40.0 g NaOH = 1.5 moles NaOH

Hint:Input moles above 2nd. number given
M= 1.5 moles NaOH/0.250 L = 6.00 M solution

Ex.#2 If 5 grams of glucose per 100 mL, how many grams of glucose in 2.00 L solution?
2.00L x 1000 mL/1 L x 5 g/100mL = 100 g glucose

Ex.#3 How many grams needed to prepare 0.250L of a 2.00M KCl solution?

Step 1: .250L x 2 mole KCl/1 L = .500 mole KCl
Step 2: .500 mole KCl x 74.65 g KCl/ 1 mole = 370

In step one, the 2 mole KCl/ 1L is the M or molarity.
In step two, 74.65 is the molar mass.

-Solution -> Small particles such as ions & atoms, do not settle but float, cannot be seperated by filter or membranes

-Colloid -> larger, molecules or groups of ions, do not settle, can be seperated by membranes but not filters

-Suspension -> largest of all three, can be seen in solution, settles to bottom, can be seperated by both

-Osmosis -> movement of water into and out of Cells of plants and animals through the "semi-permiable membranes"

-Semi-permiable membranes -> a membrane that permits the passage of certain substances while blocking or keeping in others

Calorie -> the amount of heat needed to raise the temperature of exactly 1 gram of water by exactly 1 degree Celsius. Kilocalorie is 1000 calories.

calorie (nutritional) -> The caloric values are the Kilocalories per gram of the 3 types of food: Carbohydrates, fats, and proteins

Carbohydrates = 4 Kcal/ 1 g
Fat (lipids) = 9 Kcal/1 g
Protein = 4 Kcal/ 1 g

-Solids ->rigid shape, atoms moving side to side fast, fixed volume with definitive shape

*liquid -> fixed volume, no fixed shape, atoms moving random over each other,

*gases ->fill any volume and have no shape. The atoms are floating or bouncing of walls of container.

-Changes of state ->Matter undergoes a change of state when it is converted from one state to another (solid->liquid->gas). When heat is added to a solid, the particles in a the rigid structure begin to move faster. At a temperature called MELTING POINT(or BOILING POINT for liquids), the particles gain sufficient energy to overcome the attractive forces that hold them together and become liquid.

-Endothermic reaction -> When energy is transferred INTO a system to maintain a constant temperature as a process occurs
Ex. When water on you skin (the system in this example) vaporizes, the heat (the energy) goes from your body into the water. Thus you are cooled.

*Exothermic ->When the energy is transferred OUT OF the system.
Ex. When carbon dioxide condenses from a gas to a solid, the energy was transferred out of the system or the CO2 gas.

*Activation energy ->The minimum kinetic energy that reactant molecules must have to be converted to product molecules.

-Chemical Equilibrium -> When a chemical reaction takes place in the gas phase or in a liquid solution, the concentrations of the reactants decrease and the concentrations of the products increase. When both the concentrations of the reactants and products remain constant. So, for a specific reaction, the equilibrium state will be the same, no matter what the direction of approach to equilibrium.

Ex.CH3COOH(aq) --> CH3COO(aq) + H.
or CH3COO(aq) + H -->CH3COOH(aq)
No matter which side you start from, you will get the other.

HEAT = The amount of thermal energy required to raise an objects temperature by 1 degree Celsius.

Temperature = A physical property that describes the direction of spontaneous transfer of thermal energy between objects.

Difference = Heat is measured in calories. Temp in Celsius. Temp is a straight measurement whereas HEAT is contingent on the object.

Nobody besides Shogun posts in here :confused:

Ah well... Chemistry sucks!

Originally posted by kreator
Nobody besides Shogun posts in here :confused:
Me and Chris are the first two to post in here....feel special shogun....we'll probably be the last!:lol:

http://members.aol.com/cwjenk/joshers.gif

::stumbles in drunk::

::drops 40oz::

whe.rerer is.. i be?..