Alkanes, Alkenes, Alkynes & Halides, Nitro, Alcohol, Ketones, Aldehydes--By Nemo Jin

Alkane
--all carbon atoms bonded by single bond
--general form "CaH2a"
--alkyl groups: alkane lost one hydrogen

Alkene & Alkyne
--"ene" double bonded carbon atoms
--"yne" triple bonded carbon atoms
--same naming rules, give double/triple bond the lowest number
--larger groups are diagonal: trans
--larger groups are at either bottom or top: cis

Ex.

 Ex.

Functional Groups
--most reactive part of the molecule
--insoluble in water
--F is less reactive; Cl, Br are the most reactive ones
--NO2: tend to be explosive

           F = fluoro
            I = iodo
          Cl = chloro
          Br = bromo
      NO2 = nitro


Ex.

Alcohol
--using the largest chain containing the OH group
--replacing the "e" ending in parent hydrocarbon chain with "ol"
--give OH the lowest number

general form:

Ketone &Aldehyde

--Aldehyde:

   -double bonded oxygen at the end of main chain

   -change the ending to "al"

--Ketone:

   -double bonded oxygen that's not on either end

   -change the ending to "one"

for more info:

http://www.brooklyn.cuny.edu/bc/ahp/LAD/C4c/C4c_aldehydes.html

Ester, Ether, Carboxylic Acids and Amines - By Sally Chen

Ester
- formed by 
- alcohol + carboxylic acid = ester
- fruity smell
- main chain:  drop "e" add "oate"
- counting starts on the double bonded oxygen end

Ether
- formed by 
- highly flammable
- insoluble in water
- good solvent for organic compounds
- side chain:  drop "e" add "oxy"
- counting starts on the oxygen end


Carboxylic acids
- formed by 
- can be neutralized by a base
- main chain:  drop "e" add "oic acid"
- counting starts on the double bonded oxygen end


Amines
- formed by 
- base
- primary amine = 1 carbon chain
  secondary amine = 2 carbon chain
  tertiary amine = 3 carbon chain
- closely related to NH3
- soluble
- fishy smell
- add "amino" between parent chain and side chain(s)
- counting:  whichever way makes the numbers smaller

I don't know how it just doesn't work out with the "Insert a Video" button, so here:
http://www.youtube.com/watch?v=mAjrnZ-znkY

Electronegativity, Polarity and VSEPR--By Tina Zhao

Electronegativity
- The attraction an atom has for the shared pair of electrons in a chemical bond
- It is the difference in electronegativity between two atoms that determines the degree of electron sharing which occurs between the two atoms
- Electonegativity refers to how much atoms want to gain electrons
- The top right corner of the periodic table has the highest electronegativity.Fluorine is the MOSTelectronegativity element, and the lowest electronegativity value is Francium with a value of 0.7
- If an atom has high Electronegativity value indicates that it readily pull on electrons in  a bond
-If an atom has low Electronegativity value indicates that it doesn't readily pull on electrons within a bond
- Electronectivity increase as you go across a row from left to right, and decrease as you go down a group
- The scale that is most commonly used to messure electronegativity is called the Pauling scalt , this scale range from 0.7 to 4.0
-High electronegativity values have high ionization energy because they strongly attract their valence electron and they are difficult to remove
- If the electronegativity difference < 0.5 it is a COVALENT bond
- If the electonegativity difference greater and equal the 0.5 or less and equal than 1.8 it is A POLAR COVALENT bond

Polarity

- Describes a molecule's electrical balance

- If there is an imbalance with electrical charge, then a molecule is polar

- If the electrical charge is the same strength on all sides of the molecule, then it is nonpolat

Polar Covalent Bonding

- electonegativity difference between 0.3 and 1.6 are considered to be covalent but with unequal sharing of elecreons , because the bond has slightly positive and slightly negative poles that form at each end

- Higher electronegativity will form a PARIAL NEGATIVE charge, and lower electronegativity will form a PARTIAL POSITIVE charge 

- An arrow sigh is usually used to indicate the migration of electons towards the more electronegativity

EX:

For CH3C1, C has a value of 2.5; H has a value of 2.1 and Cl has a value of 3.0.

...................H (2.1)
....................|
H(2.1) --------- C(2.5) ----------- Cl (3.0)
....................|
...................H (2.1)

Between the Hydrogen's and carbon there is a difference of 0.4, and between the carbon and chlorine there is a difference of 0.5.

VSEPR (The Valence Shell Electron Pair Repulsion

- For polyatomic molecules containing 3 or more atoms, one of the atoms is called the central atom to which other atoms are linked.
- The geometry of a molecule depends upon the total number of valence shell electron pairs (bonded or not bonded) present around the central atom and their repulsion due to relative sizes and shapes.
- If the central atom is surrounded by bond pairs only. It gives the symmetrical shape to the molecule.
- If the central atom is surrounded by lone pairs (lp) as well as bond pairs (bp) of then the molecule has a distorted geometry.
- The relative order of repulsion between electron pairs is as follows: lp – lp > lp – bp > bp – bp.
A lone pair is concentrated around the central atom while a bond pair is pulled out between two bonded atoms. As such repulsion becomes greater when a lone pair is involved.

linear molecule :with a 180^o angle 

trigonal planar :with angle of 120

- If the electronegativity difference >1.8 it is an IONIC bond

Chemical Bonding & Electronic Dot Structure -- by Ria Park

Chemical Bonds

Chemical Bonds 

• are formed when the electrons of one atom are attracted by the nucleus if another atom.
• are formed with various degrees of sharing of electrons between two atoms
• COVALENT BOND is formed when the electrons are shared equally between two atoms
• When the electrons of one atom are given away completely to another atom, both a positively charged ion and a negatively charged ion are formed
• The force holding the two ions together is called an IONIC BONDS

Covalent Bond

Ionic Bond

Lewis Structure

• represents valance electrons.
• uses dots to represent electrons, focuses on an atom's valence electrons only.
• The electrons that are in pairs are Lone pairs or Nonbonding electrons.
• These are not used to bond since the orbital they are in already has its full complement if electrons.
• The unpaired electrons are Bonding electrons. They are capable of making one single covalent bond.
• An atom needs to have 2 bonding electrons when we make a double covalent bond.
• To make a triple covalent bond, an atom needs 3 bonding electrons.

Now single covalent bond is forme

Double Bond

Triple Bond

Example of Lewis Structure

History of the Atom - By Sally Chen

Aristotle

- Democritus:  suggested that the differences between substances were the direct result of differences in the size and shape of tiny, uniform, unbreakable particles.

- Aristotle:  4 basic elements:  water, air, fire and earth.

- Antoine Lavoisier:  created the first law of the conservation of mass.

- John Dalton:  created Dalton’s Atomic Theory, which is a combination of all discoveries about atoms.
- J. J. Thomson:  He discovered the existence of electron in 1897.  He found it was about 2000 times less than the mass of hydrogen.

- Ernest Rutherford:  He discovered the atomic nucleus and presumed the nuclear structure of the atom and predicted the existence of the neutron.

- Robert Millikan:  He accurately determined the charge carried by an electron, using “falling-drop method”.  He also demonstrated that this quantity was a constant for all electrons.

- Marie Curie:  She and her husband Pierre Curie isolated the elements polonium and radium.  She also developed methods for the separation of radium from radioactive residues.

Albert Einstein

- James Chadwick:  He discovered the neutron, and that it had about the same mass as a hydrogen atom.

- Max Planck:  He discovered that light was released by heat sources in a particular pattern of frequencies for different elements.  Each frequency of light corresponded to different sets of colors of lights seen by our eyes (lowest to highest:  red, orange, yellow, green, blue, purple, and violet).

- Albert Einstein:  In 1905 Einstein projected a theory that light was made up of localized particles.  He also defined detailed equations on light wavelengths and frequency differences within the same light.  He named packets of light energy photons.  Einstein believed that each atom oscillates independently instead of joining to others.

Joseph Louis Proust

- Niels Bohr:  electric fields between negatively charged electrons and a positively charged nucleus must hold electrons in their orbits.  He thought that electrons could circle at different orbit levels above the nucleus depending on how much energy they had.  When electrons jumped to lower levels, Bohr suggested that energy would be released as light.  The diagram of his version of atom is called the Bohr Diagram.

- Louis De Broglie:  He discovered the wave nature of electrons.  He had a theory that the behavior of the electron could also be better understood not just as a particle, but as both a particle and a wave.

- Erwin Schrodinger:  He created an equation describing how Broglie’s theory would be possible, not only for atoms and parts of the atom, but even for large objects – maybe even for the entire universe.

- Joseph Louis Proust:  He discovered the law of definite proportions, also known as Proust’s law, which states that chemical compounds always have the same fraction of each element in them by mass.

- Henri Becquerel:  He was the first person who discovered radiation.

History of Periodic Table--Nemo Jin

Long time ago, a group of people believed that they could turn metals into pure gold. These people were called alchemists. Although they were not successful, many different elements were discovered by these alchemists, including gold, silver, tin, copper, lead and mercury. However, the first scientific discovery of an element was in 1649, the discovery of phosphorous by Hennig Brand.

In the next 200 years, a total of 63 elements had been discovered, and scientists began to recognize patterns in properties and began to develop classification schemes.


In 1863, John Newlands, a English chemist divided 56 elements into 11 groups, based on their characteristics. He also proposed the Law of Octaves,which stated that any given element will exhibit analogous behavior to the eighth element following it in the table.

                                             (John Newlands' Periodic Table)

(Meyer's 1864 textbook included a rather abbreviated version of a periodic table used to classify the elements, but unfortunately for Meyer, Mendeleev's table was the first one available to the scientific community)


      “Father of Periodic Table"
In 1869, Russian chemist Dimitri Mendeleev arranged chemical elements by their atomic masses.  He also accurately predicted the properties of some undiscovered elements, leaving spaces open in his periodic table for them. His contribution to the development of periodic table was usually considered as the foundation of modern periodic table. 

In 1894, Sir William Ramsay and Lord Rayleigh discovered the noble gases which did not fit any of the known periodic groups. Because of the zero valency of the elements, noble gases were added to the periodic table as group 0

In 1911, A. van den Broek proposed that the atomic weight of an element was approximately equal to the charge on an atom. This charge, later termed the atomic number, could be used to number the elements within the periodic table.

The last major changes to the periodic table was in the middle of the 20th Century.


Glenn Seaborg 
--discovery of elements from 94 to 102 
--rearrangement of the periodic table (placing the actinide series below the lanthanide series) 
He was awarded the Nobel Prize in chemistry for his work. Element 106 has been named seaborgium (Sg) in his honor.

Electronic Structure of the Atom--By Tina Zhao

Electronic Structure of the Atom
- The electronic configuration of an atom is notation that describes the orbitals in which the electrons occupy and the total number of electrons in each orbital
-Helps to understand the structure of the periodic table of elements

Energy Level
- is the amount of energy, which an electron in an atom can possess "n" is the number of the energy level
- the energy difference two particular energy levels are called the quantum of energy


Ground State: When all the electrons of an atom are in their lowest possible energy level
Excited State: When one or more of an atoms's electrons are in energy
An orbital is the actually region of space occupied by an electron in a particular energy level
A shell is the set off all orbital having the same n-value
A sub-shell is a set orbital in same level

For a given value of "n", different types of orbitals are possible:
n=1; only the s-type
n=2; s and p- types
n=3; s,p,and d-types
n=4; s,p,d,and f-types

* A maximum of 2 electrons place in one orbital

Writing Electronic configurations for Neutral Atoms

- Always start with lowest energy level first 

- Figure out how many electron you have (neutral number= atomic number) then start  at the lowest energy level (1s)

- Each electrons has an opposite spin

* the 2 electron in the 2p occupy separate suborbitals and are not paired up 

Writing Electronic configurations for ion

Negative ion: Add electrons (equal to the charge) to the last unfilled sub-shell, starting where the neutral atom left off

Positive ion: Start with the neutral configuration, and then remove electrons from the outmost shell first

Core Nation

- The set of electrons for an atom can be divided into two subsets; the core electrons and the outer eletrons

- The core of an atom is the set of electrons with the configuration of the noble gas

- The outer electrons consist of all elections outside of core. Core electrons  normally take part in chemical reaction

- Locate the atom and not the noble gas at the end of the row above the element

Predicting the number of Valence Electrons

- are electrons which can take part in chemical reactions 

- or are all the electrons in an atom EXCEPT those in CORE AND IN FILLED d OR f -sub-shells

Atomic Structure -- by Ria Park

Atomic Structure


Subatomic Particles

• Neutron = Large with no charge; location=nucleus
• Proton = Large with positive charge; location=nucleus
• Electron = small with negative charge; location=cloud surrounding the nucleus - A neutral atom has no overall net charge.

    Atomic Number: The Proton Number

• found in the nucleus of an atom
• has no overall electric charge

Atomic Number = # of protons - # of electrons

Ions

• Atoms that have gained or lost electrons are called Ions
• Most atoms are capable of either gaining or losing electrons. A few elements, like hydrogen, are able to do both -- by accepting electrons from or giving electrons to, either atoms.
• An ion is an electrically charged atom.
• Negatively-charged ion: anion = when electron are added to a neutral atom
• Positively-charged ion: cation = when electron are subtracted to a neutral atom

Mass Number

• is the number of protons and neutrons or atomic mass number since atomic # = the # of neutrons
• Atomic mass ≠ # of protons + #of neutrons
• Number of neutrons = Mass number - protons

Atomic Mass

• The average mass of an element's isotopes
• since most of the mass of an atoms is concentrated in the protons and neutrons located in the nucleus.
• If a neutron is added to an element's nucleus, a heavier version of the same element (isotope) will be produced.

Isotopes

• are atomic species having the same atomic number (protons) but different atomic masses/mass numbers (neutrons)

Periodic Trends - By Sally Chen

Density Graph
Density:  the mass of a substance per unit volume.
Down a group:  increase
Across a period:  increase then decrease

General Shape

Down each group (from left to right)

Melting and Boiling Point
Melting point:  the temperature at which a substance changes from a solid to a liquid.
Boiling point:  the temperature at which a substance changes from a liquid to a gas.
Down a group:  increase
Across a period:  increase then decrease

General Shape

Down some groups

Ionization Energy
Ionization Energy:  the energy required to remove electrons from gaseous atoms or ions.
Down a group:  decrease
Across a period:  increase

General Shape

Down each group (from left to right)

Electronegativity
Electronegativity:  a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself.
Down a group:  decrease
Across a period:  increase

General Shape

Down each group (from left to right)

Atomic Radius
Atomic Radius:  a measure of the size of the atom.
Down a group:  increase
Across a period:  decrease

General Shape

Down each group (from left to right)

Lab 6D -- by Ria Park

Lab 6D : Determining the Limiting Reactant an Percent Yield in a Precipitation Reaction

Objectives

1. to observe the reaction between solutions of NaCO₃and CaCl₂
2. to determine which of the reactants is the limiting reactant and which is the excess reactant
3. to determine the theoretical mass of precipitate that should form
4. to compare the actual mass with the theoretical mass of precipitate and calculate the percent yield

Supplies

• Equipment: centigram balance, 2 graduated cylinders(25ml), beaker(250ml), wash bottle, filtering apparatus(ring with stand, Erlinmeyer flask(250ml)+funnel), filter paper, lab apron, safety goggles
• Chemical Reagents: 0.70M  NaCO₃solution, 0.50  CaCl₂solution

Procedure

Part Ⅰ= the Precipitation Reaction(Day 1)

1. lab apron + safety goggles
2. obtain 2 clean, dry 25ml graduated cylinder and one 250ml beaker.
3. 25ml of NaCO₃(aq) in one cylinder & 25ml of CaCl₂(aq) in the other. Record volumes.
4. Pour contents of both cylinders into the beaker. Observe. Record. Allow the contents of the beaker to sit undisturbed for 5 min to see what happens to the suspended soild particles. Meanwhile, do step 5.
5. Get a piece of filter paper and put names on it with a pencil. Weigh and record the mass of it. Set up a filtering apparatus.
6. Lightly wet the filter paper the funnel to keep it in place(using the wash bottle). Swirt the beaker to suspend the precipitate. Pour it carefully & slowly into the filter funnel. Use wash bottle to raise the remaining precipitate from the beaker.
7. Rise the precipitate in the filter paper with wash bottle(to remove NaCl)
8. Remove the wet filter paper and place it on a folded paper towel. Put filter paper(with CaCO₃) in the assigned location to dry.
9. Clean up.
10. Wash hands.

Part Ⅱ= Weighing the dried precipitate(Day 2)

1. Weighing and recording the mass of dry filter paper + CaCO₃precipitate.

Reagent Disposal

Rinse all solutions down the smile with sufficient water. Solid go into the designed containers.

Percent Yield and Purity--- By Tina Zhao

percent Yield= The yield is the amount of product you obtain from a reaction. Suppose we own a factory that makes fertilizers or paint. We will want the highest yield possible, for the lowest cost.

The formula for percent yield is:

Example:

The medical drug aspirin is made from salicylic acid. 1 mole of salicylic acid gives 1 mole of aspirin. Given that the chemical formula for salicylic acid is C₇H₆O₃ and the chemical formula for aspirin is C₉H₈O₄.

In an experiment, 100.0 grams of salicylic acid gave 121.2 grams of aspirin. What was the percent yield?

Solution:

Step 1: Calculate the M_r (relative molecular mass) of the substances.

A_r : C = 12, H = 1, O = 16
So, M_r : salicylic acid = 138, aspirin = 180.

Step 2: Change the grams to moles for salicylic acid

138 g of salicylic acid = 1 mole
So, 100 g = 100 ÷ 138 mole = 0.725 moles

Step 3: Work out the calculated mass of the aspirin.

1 mole of salicylic acid gives 1 mole of aspirin
So, 0.725 moles gives 0.725 moles of aspirin
0.725 moles of aspirin = 0.725 × 180 g = 130.5 g
So, the calculated mass of the reaction is 130.5 g

Step 4: Calculate the percent yield.

The actual mass obtained is 121.2 g
So, the percent yield = 121.2 ÷ 130.5 × 100% = 92.9%

Percent purity= sometimes, the reactant we use is not pure, so before we can calculate how much product will form, we need to use percent purity to calculate how much reactant that actually is availablt to react.



The formula for percent yield is:





The medical drug aspirin is made from salicylic acid. 1 mole of salicylic acid gives 1 mole of aspirin. Given that the chemical formula for salicylic acid is C₇H₆O₃ and the chemical formula for aspirin is C₉H₈O₄.

In an experiment, 100.0 grams of salicylic acid gave 121.2 grams of aspirin. What was the percent yield?

Solution:

Step 1: Calculate the M_r (relative molecular mass) of the substances.

A_r : C = 12, H = 1, O = 16
So, M_r : salicylic acid = 138, aspirin = 180.

Step 2: Change the grams to moles for salicylic acid

138 g of salicylic acid = 1 mole
So, 100 g = 100 ÷ 138 mole = 0.725 moles

Step 3: Work out the calculated mass of the aspirin.

1 mole of salicylic acid gives 1 mole of aspirin
So, 0.725 moles gives 0.725 moles of aspirin
0.725 moles of aspirin = 0.725 × 180 g = 130.5 g
So, the calculated mass of the reaction is 130.5 g

Step 4: Calculate the percent yield.

The actual mass obtained is 121.2 g
So, the percent yield = 121.2 ÷ 130.5 × 100% = 92.9%

Stoichiometry--By Nemo Jin

Definition:

--ratio between the amount of reactants and the amount of products produced by the reactants in a chemical reaction.

--it is based on the fact that all atoms are conserved in a chemical reaction.

Calculation:

Question: 

How many moles of Cl2 are needed to produce 3.4 moles of NaCl in the chemical reaction which sodium metal and chlorine gas combine to form solid sodium chloride?

Step 1:

Write a balanced equation.

2 Na(s) + Cl2(g) --> 2NaCl(s)

Step 2:

Find the ratio for NaCl to Cl

Cl2/NaCl = 1/2

Step 3:

Convert into NaCl

3.4 moles NaCl x 1 mole of Cl2/2 moles of NaCl = 1.7 moles of Cl2

Excess and Limiting Reactants By Sally Chen

The green reactant is the excess quantity,
whereas the red one is the limiting reagent.

- Reactions do not take place exactly as how they are described in balanced chemical equations.
       -Reason:  conditions necessary for the reaction to take place may not be present (ie. pressure, temperature, concentration, etc.)
- It is necessary to add more of one reactant than the amount we get from stoichiometry calculations.
       -Reason:  it is impossible for every atom/molecule of the reactants to come together.
- Limiting Reactant/Reagent:  the ONE reactant that is used up in a chemical reaction.
- Excess Quantity:  the reactants that are left over.

- How much of the excess quantity is left?
       Steps: 1. balance equation
                 2. convert grams of reactant #1 to grams/moles of product #1
                 3. convert grams of reactant #2 to grams/moles of product #2
                 4. compare the answer u get from 2 and 3, the lower one is the amount that will be produced.
                 5. calculate the grams of the excess reactant needed in this reaction.
                 6. calculate the difference between grams of the actual grams of the excess reactant provided and # you get form step 5.

Types of Reaction (including activity series and solubility) -- By Nemo Jin

Energy Diagrams and Calculations--By Tina Zhao

Energy Diagrams:
















Important Terms:








Energy of reactants: Total potential energy of all reactants in the reaction




Energy of product: Total potential energy of all products in the reaction




Energy of the activated complex: potential energy of the "transition state" between reactants




and products.




Activation energy: The energy that must be added to get the reaction to progress




Enthalpy: It is the energy of products - energy of reaction 




There are some examples




（http://www.sciencegeek.net/Chemistry/taters/energydiagram.htm）


















Energy in the Equation






- The energy absorption or release can be placed directly in the equation.




Exothermic : Reactions have the energy term on the right hand side and a negative H




example: CH4 + 2O2 ------CO2 + 2H2O + 812KJ






Endothermic: Reaction have the energy term on the left hand side and a positive H




example: I2 + Br2 + 81.5KJ -------2IBr










Energy Calculations




- The value of H change of a reaction and is expressed in KJ per mole of one of the chemical.
- We ignore the negative in conversion calculation because we use words




example: Using the follow reaction, how many moles of CH4 are needed to produce 2100KJ 




of energy? 










CH4 + 2O2 ------- CO2 + 2H2O + 812 KJ








2100KJ x 1mole of CH4 / 812KJ = 2.6moles of CH4

Endothermic/exothermic Reaction -- by Ria Park

All chemical reactions make changes in energy. Those are:

  Endothermic Reaction:

• This reaction absorbs energy.
• e.g. one ice pack melts. -> it absorbs energy so that ice becomes water.
• It takes more energy to break bonds.

  Exothermic Reaction:

• This reaction release energy.
• 2 explosion explode. -> it release energy.
• It takes takes less energy to break bonds.

> Chemical bonds hold molecules together.

• add energy to break bonds
• lose energy to to join together again.

> Enthalpy(H) is the heat contained in the reactions.

http://www.youtube.com/watch?v=1B3bb9d3WOk

Balancing Equation --By Tina Zhao

Balancing Equation:
- The aim of balancing equation is to make the number of atoms of each kind on the reactant side equal to those on the product side. 


Rule:
-Chemical formulas of reactants are listed on the lefthand side of the equation. 
-Products are listed on the righthand side of the equation. 
-Reactants and products are separated by putting an arrow between them to show the direction of the reaction. Reactions at equilibrium will have arrows facing both directions. 
- First balance the atoms which only occur in one molecule on each side of equation
Balance whole group whenever possible, rather than considering the atoms of groups separately
- Be systematic: do not jump all over an equation balancing a bit here and bit these
-balance atoms which occur in elemental from last. By elemental form we mean that the atoms are not combined with atoms of a different kind.

Example for balancing equation:

step 1:

step2:

step3:

step4:

http://www.files.chem.vt.edu/RVGS/ACT/notes/scripts/bal_eq1.htm

http://www.sciencegeek.net/Chemistry/taters/EquationBalancing.htm

http://misterguch.brinkster.net/PRA008.pdf

Open these links, these links may help you for balancing equation. 

Ionic Compound:

Ionic compounds are basically defined as being compounds where two or more ions are held next to each other by electrical attraction. One of the ions has a positive charge (called a "cation") and the other has a negative charge ("anion").I

example:

NaCI :  Sodium Chloride

K2SO4：potassium Sulphate

FE2O3:  Iron(III）Oxide

Covalent Compound:

-Bonding between non-metals consists of two electrons shared between two atoms. 

Mono: 1 Di:2  Tri:3 Tetra:4 Penta: 5 Hexa:6 Hepta:7 Octa:8 Nona:9 Deca:10 Hendeca:11 Dadeca:12