Functional Groups

        In previous classes, we went over alkanes, alkenes, and alkynes. Now we are going to go over the chains that contain not only carbon and hydrogen but many other elements.
      Halides and Nitro Compunds:  When halogens are added into the compund, the names of these elements will be placed infront of the parent chain when naming. The halogens used are F-Fluoro, Cl-chloro, Br-bromo, and I-iodo. And nitro is also used too. The names will end with -ane.
      Alcohols: You can tell when the compund is an Alcohol when there is a branched OH somewhere in the middle of the compound. The ending of the name is -ol .When there are two or more OHs add diol, or triol to the ending.
      Aldehydes: Double bonded oxygen at the end of the chain. The name ends with -al.
      Ketones: Double bonded ocygen in the MIDDLE of the chain (not on either end). Ends with -one when naming.
     

Chemical Bonding

         In Chemical Bonding, there are three types of bonding. There are covalent bond, polar covalent bonds, and ionic bonds.
        * Electronegativity- the attraction of an atom for for a shared pair of electrons.
        Firstly is the covalent bond. A covalent bond is when two atoms are sharing a pair of electrons relatively evenly. When the electronegativity between two atoms are 0.5 or less, it is a covalent bond.


http://scienceelearning.wordpress.com/page/7/
        Example: F and F
                        |3.98-3.98=0|
                        Since the electronegativity difference is 0, it is a covalent bond.
        Next is the polar covalent bond. A polar covalent bond occurs when there is an unequal attraction for shared electorns. One atom will end up with a slightly negative charge and the other will end up with a slightly positive charge. For polar covalent bonds, the attraction is stronger so it is harder to seperate the atoms.
      Example: B and Cl
                       |3.16-2.04=1.12|
                       Since the electronegativity difference is over 0.5 and under 1.8, it is a polar covalent bond.

      Lastly is the ionic bond. Unlike the covalent and the polar covalent bond, the ionic bond does not share the electrons. An ionic bond is made by the attraction of two oppositely charged ions.When the electronegativity difference is 1.8 or more, it is considered a ionic bond.
       Example: K and Br
                       |2.96-.0.82=2.14|
                       Since the electronegativity difference is over 1.8, it is an ionic bond.

http://alevelnotes.com/Bonding/130

                                                                       -Victoria

Organic Chemistry

Alkanes (Straight chain with no branches)
- Hydrocarbon ---> A compound containing only hydrogen and carbon
- They are saturated because each Carbon atom is bonded to the maximum possible number of other atoms
- Carbon atoms are bonded by single bonds
- the names of hydrocarbons end in '-ane'

Name of parent compound chain
- The name is of the hydrocarbon is determined by the number of carbon it has

 

- Alkane formula = CnH2n+2

Alkyl (Branched Hydrocarbons)

- Alkyl is an alkane which has lost one hydrogen atom

eg. CH4----> Ch3-

- Naming: changing the "ane" ending of the original hydrocarbon to "yl"

eg. methane = CH4 ----> Methyl CH3-

Rule of Naming Alkyl

- include the carbon number at which the alkyl group is attached

- a dash
- the name of the alkyl group
- finally, the name of the parent hydrocarbon chain, to which the alkyl group is attached

eg. CH3-CH-CH2-CH2-Ch3

                '
              CH3                                    This is called 2-methylpentane

- Catherine

Alkenes & Alkynes

• carbon is able to form double/triple bonds with other carbon atoms
• when multiple bonds are formed, less hydrogen will attach to the carbon atom
• naming rules are similar to alkanes, the only difference is "ene"

Alkenes, hydrocarbons with one or more double bonds between carbon atoms which leads to an "unsaturated" hydrocarbon.

Ex: CH2=CH2 ethene

      CH2=CzH- CH3 propene/propane

Ex: Name the following compound.

CH3-CH2-C=CH-CH3

                   | 

                  CH2-CH3

Trans & Cis Butene

• if 2 adjacent carbons are bonded by a double and have side chains attached to them, it is possible for 2 compounds to be made

Alkynes, with one or more triple bonds located between carbon atoms leads to an "unsaturated" hydrocarbon.

The ending is changed from "ane" for alkane and "ene" for alkene to "yne" for alkyne.

Check out this link for some extra help!

http://www.youtube.com/watch?v=l6m7zOto9oU

-Lauren

Electron Dot and Lewis Structures

Drawing Electron Dot and Lewis Structures

• the nucleus is represented by the Atomic symbol
• for individual elements you have to determine number of valence electrons
• electrons are represented by dots :      .   
• 4 orbitals (max. of 2 per each orbital)
• each orbital has 1 electron before they pair up
• the dots are placed into 4 groups of one/ 2 electrons, with 8 electrons representing a closed shell (noble gas configuration)
• the dots are placed on the 4 sides in pairs

Ex:       Li .

Each bond in the structural formula represents 2 electrons. All valence electrons must be used. Each element must have a full valence shell (8 electrons), except hydrogen which only needs 2 electrons.

Ex:      C2H6       Carbon- 4e  Hydrogen- 1e
A structural diagram is one that shows each bond as a line. Each line represents 2 dots. Lone pairs aren't shown in structural diagrams:        H       H     
                                                                            H-C    -  C -H
                                                                                H        H    <----(structural lines connecting bottom and top H's with the C's.)

Lewis Structures

• structural diagrams show the number of bonds in a compound
• electron dot diagrams show the electrons involved in the bond
• if you know the structure of a molecule it means you know which atoms are bonded to which

Octet Rules

• H only needs 2 electrons
• CNOF (carbon, nitrogen, etc) always follow the octet rule

Rules for Writing Lewis Structures

For ex: CCl4

1. The central atom (H and F are never in the center)

• if a metal is present, place it in the center
• if a molecule has only 1 atom of a particular element and several atoms of another, the single one is the one in the center
• place the atom that needs the most electrons in the center

    2.   Place one pair of the electrons into each bond

    3.   Can't up the total number of valence electrons in a molecule. Adjust the number by subtracting one
          electron, for every positive charge. Adding one for negative charges.

    4.   Find the number of valence electrons remaining.

    5.   Use the number of valence electrons remaining to complete the octets of the atoms bonded to the central atoms.

   6.   Then place any remaining electrons on the central atoms in pairs.

   7.   If the central has less than an octet, make multiple bonds.

   8.   Replace each pair of electrons engaged in a bond with a dash "  - "


Check out this link for extra help!
http://www.youtube.com/watch?v=K7EAteDWxPQ

-Lauren

The History of the Periodic Table and the Periodic Table Families

          The very first scientist arrange elements in order is an English chemist, John Newlands. He is the one who pioneered the discover of the periodic table. Newlands arranged the elements by their relative atomic weights in 1863.
         The next year in 1864, Dmitri Mendeleev a Russian chemist, came up with the very first version of the peridic table. Unlike John Newlands, Mendeleev put the elements in order by similar properties in stead of their relative atomic mass. Mendeleev left blanks in the periodic table for the elements yet to be discovered.
        Glen Seaborg is the last to make changes in the modern periodic table. Seaborg dicovered elements 94 to 102. Element  106 has been named after him.
      
        For the organization of the periodic table, the horizontal rows are called a period. Vertical columns are called families or groups.
        Alkali metals: highly reactive metals that are located in group 1 in the periodic table.
        Alkaline earth metals: reactive metals that are located in group 2 in the peridoic table
        Halogens : Non metals that are highly reactive and react with water, located in group 17.
        Noble Gases: odourless, colourless, non metals that have low reactivity because their valence sheels are full. They are in group 18.
       Lanthanide Series : elements 57-71
      Actinide Series : elements 89-103, all are radioactive.

Atomic History

Aristotle (384 BC – 322 BC)

-         Believed you could divide matter an infinite number of times

-         Believed world was made of earth, fire, water and air.

-         These elements were acted upon by gravity and levity

Democritus (460 BC)

-         Believed matter was made up of tiny particles called ATOMS

-         Matter could not be divided indefinitely

-         Could not prove his hypothesis

Lavoisier (1777)

-         founded the law of definite proportions

-         discovered oxygen and hydrogen

-         reasoned that the ratio between elements would always be the same in a compound no matter how much of that compound was available.

Dalton (1800s)

            Five Point Atomic Theory

-         All matter is made up of atoms

-         Atoms of a given element differ from the atoms of another element

-         All atoms of a given element are identical

-         Chemical reactions do not change the elements but change the way the elements are grouped together

-         Atoms cannot be created, divided or destroyed through chemical process. 

Henri Bequerel(1851)

-         discovered radioactivity

-         studied the effect of xrays on photographic film

-         some chemicals decomposed and gave off penetrating rays

Thomson (1897)

-         Discovered the electron

-         Used a cathode ray tube to experiment with the magnetic deflection

-         Created the plum pudding model

-         This model states that negatively charged electrons exist randomly throughout an atom. No mention of protons or a nucleus.

Bohr

-         Created the bohr model of the atom

-         Electrons do not spiral around the nucleus – they orbit at certain allotted distances from nucleus

-         Atoms radiate energy- jump from higher to lower orbits

-         His model had protons, electrons and neutrons

Rutherford

-         Changed the arrangement of particles in an atom

-         Gold foil experiment- shot alpha particles through gold foil – some of them bounced back

-         He concluded that atoms have a positive dense centre and electrons orbit outside it

-         This was the first planetary model – electrons spin around the nucleus.

Millikan (1921)

-         Discovered the negative charge on the electron

-         Used the oil drop experiment and observed the speed of the particles

James Chadwick (1932)

-         discovered the neutron

-         Observed that previously thought gamma radiation was radiation from neutral particles

- Candace

Trends on the Periodic Table

Last class we learned some terms in chemistry. Let's review them!
Atomic Radius: The atomic radius of a chemical element is a measure of the size of its atoms
Melting Point: The temperature a chemical reaches when it melts
Boling Point: The temperature a chemical reaches when it boils
Ionization Energy: The energy required to move an electron from an atom
Electronegativity: The tendency of an atom or radical to attract electrons in the formation of an ionic bond

The Trend of Periodic Table
- Elements close to each other have similar characteristics
Atomic Radius  - radius decreases moving → on the table
 - increases moving ↓ (a family)
Melting Point and Boiling Point - elements in the center of the table of highest MP and BP
- Noble gas has the lowest
- Increases moving → until the middle of the table
Ionization Energy - energy increases going ↑ and →
- Noble gases have the highest ionization energy because they have a full valence shell
Electronegativity -  energy increases going ↑ and →
Metallic Properties - elements become more metallic going ↓ a family

Visit  http://www.ptable.com for a dynamic and fun periodic table to visualize the trends!

- Catherine

Atomic Structure

Subatomic Particles of an Atom:   Neutron, Proton, and Electron.

A neutral atom doesn't have any charges and the number of protons will equal the number the of electrons in the atom.

# of protons = # of electrons

The Atomic Number ( Z )

Also the same number of protons in an atom. Atoms do not have an overall charge. The atomic number is the same as the number of protons which are the same as the number of electrons.

Atomic number = # of protons = # of electrons

If a proton ( ¦ p ) is added to an element's nucleus,  a new element will be created.

For ex:   19 F + ¦ p ---> 20 Ne
               9                     10

Ions

Atoms have the ability to gain or lose electrons. Not many can do both, one such as hydrogen can though. They are able to do this by accepting electrons or giving them away to other atoms. Atoms that have done so are then called ions.

# of electons = protons - charge

Ions are electrically charged atoms.

• Negatively charged ion (anion) : when an electron is added to a neutral atom. non- metals tend to gain a positive charge and become neutral.
• Positively charged ion (cation) : when an electron is taken away from a neutral atom.

Mass Number, the total number of protons and neutrons

Because, atomic number = the number of protons, then :

• the atomic mass = the number of protons + the number of electrons
• the number of neutrons = the mass number - the atomic number

Atomic Mass

• the average mass of an element's isotope
• since most of the mass of an atom is concentrated in the protons and neutrons, the atomic is very close
• the mass number plus the atomic mass (weight) are not the same thing. atomic mass is the average of the naturally occurring isotopes, while the mass number is calculated by rounding the atomic mass to the nearest whole number instead of keeping decimal points
• if a neutron is added to an element's  nucleus, a heavier version of the same element (isotope) will be produced

For ex:   19 F + 1 n ---> 20 F
                9       0             9

Take a look at the following sites. Enjoy the song!

http://www.youtube.com/watch?v=lP57gEWcisY

http://www.youtube.com/watch?v=vUzTQWn-wfE&feature=related

-Lauren

Electronic Structure of the Atom

-         The Electronic Configuration of an atom =

o       A notation - describing the orbitals in which the electrons occupy

                                 - Describes the total number of electrons in each orbital.

               * This helps us understand the structure of the periodic table!

-         Bohr proposed- electrons exist in specific energy states

- when these electrons absorb or emit energy they moves from one orbital to another.

-         Energy level = amount of energy which an electron in an atom can possess

o       n is the number of the energy level

-         Quantum of energy = the energy difference between 2 particular energy levels

-         Ground State = when all electrons of an atom are in their lowest possible energy levels

-         Excited State= when one or more of an atom’s electrons are in energy levels other than the lowest available level

-         An Orbital = the actual region of space occupied by an electron in a particular energy level

-         Shell = the set of all orbitals having the same n value.

-         Subshell = a set of orbitals of the same type.

The letters s, p, d, f refer to 4 different types of orbitals

-         a maximum of 2 electrons can be placed in each orbit.

Order of orbitals

The order in which orbitals are filled is 1s, 2s, 2p, 3s, 3p…

Writing Electron Configuration for Neutral Atoms

o       always start at lowest energy level first

1)      Figure out how many electrons you have

2)      Start at lowest energy level (1s) and keep adding electrons until you have none left

Each electron has an opposite spin represented by:  ↑ and ↓

Example: Lithium is written 1s²2s²

Writing Electron Configuration for Ions

For a negative ion- add electrons to last unfilled subshell

For a positive ion- take away electrons (in the order you put them there)

Example: Sulphur 2-

        Sulphur has 16 electrons à Sulphur 2- has 18 electrons

            1s²2s²2p⁶3s²3p⁶

Core Notation

-         Core = the core of an atom is the set of electrons with the configuration of the nearest noble gas that comes before it.

-         Outer  = consist of all electrons outside the core. Core electrons normally take part in chemical reactions.

1)      Locate the atom à note the noble gas before the element

2)      Replace the part of the electron configuration corresponding to the configuration of the noble gas with the symbol for the noble gas in square brackets.

Example:

 

Youtube Time!!

http://www.youtube.com/watch?v=JNPFR-22MPA

-Candace

Lab 6D

Last class we did 6D, where we mixed NaCO3 and CaCl2 together. A double replacement reaction during the mixing process. Precipitate, salt (NaCl2) was formed. The liquid turned white and cloudy from transparent. We measured the mass of the filter paper. In day 2, which is tomorrow, we will weigh the filter paper again and see if the mass has changed since it has absorbed Calcium Carbonate.

-Catherine

Molarity Stoichiometry and Gas Stoichiometry

Molarity Stoichiometry

*Remember the Molarity Formula

Molarity = Moles/ Litres

There are three steps to complete when given a molarity calculation in stoichometry.

Step 1: Write a balanced equation

Step 2: Map the solution (find the route to get to the answer)

Step 3: Calculation

Example 1:

Given this chemical reaction, FeCl3 + Mg(SCN)2 à Fe(SCN)3 + MgCl2, how many moles of MgCl2 would be formed if 50.0ml of 0.200 M FeCl3 is reacted with sufficient Mg(SCN)2?

Step 1: Write a balanced equation

2FeCl3 + 3Mg(SCN)2 à 2Fe(SCN)3 + 3MgCl2

Step 3: Calculations

0.0500 L FeCl3 X 0.200 mole  = 0.0100 moles    ß Find the amount of moles in FeCl3

                               1L FeCl3

0.0100 moles FeCl3 X 3 mole MgCl2  = 0.0150 moles  ß convert moles of FeCl3 to

                                        2 mole FeCl3                                 moles of MgCl2

Answer: 0.0150 moles of MgCl2

Check out this youtube video for more problems on molarity and stoichiometry!

http://www.youtube.com/watch?v=n5TaI_XR3y4

Gas Stoichiometry

*Remember: One mole of gas = 22.4L at STP

Example 1:

Given the formula Zn + HCl à ZnCl2 + H2, at STP what volume of H2 gas would be produced from 21.2g of HCl?

Step 1: Balance the equation

Zn + 2HCl à ZnCl2 + H2

Step 2: Change grams of HCl to moles of HCl

               2.12g HCl X 1 mole = 0.0581 mol HCl

                                  36.5g HCl

            Convert moles of HCl to moles of H2

            0.0581 moles HCl X 1 H2  = 0.2904 mol H2

                                              2 HCl

            Convert the moles of H2 to the volume of H2

            0.02904 mol H2 X 22.4L  = 0.651L

                                          1 mole

Answer: 0.651 L

If you are still confused check out this Youtube Video!!
http://www.youtube.com/watch?v=9Bc7igjXfYU

But when in doubt follow your mole map!

Remember that you can convert between compounds or elements using the mole ratio!!!!

-Candace

Stoichiometry Calculations

(Moles, particles, atoms)

Ex:  How many grams of Ca are produced if there are 4.24 moles of HBr?

       1).  Balance the eq'n:    2Ca+2HBr--->2CaBr+1H2 
       2). Next make a road map:  4.24 mol HBr---> ?grams Ca
       3). Now do the calculation: 4.24 mol HBr x 1 mol Ca x 80.2g Ca  = 85g Ca.
                                                                        2 mol HBr   2 mol Ca


Try some practice problems:
1) How many moles of HCl are needed to produce .76 g of CaCl?
2) How many grams of Ca are needed to produce  1 molecule of H?
3) How many atoms of H will be formed when 3.42 moles of Cl are formed?
4) How many grams of CaCl are needed to form 8.19 moles of HCl?

Check out this link: http://www.youtube.com/watch?v=jVtP9VSrdGw&feature=related
If catchy songs help you study, then this link will do the trick.

-Lauren                                                                                                                              

Stoichiometry

What is Stoichiometry?
- it's the study of the relationship between the number of reactants needed to produce the product and the amount of product produced

What does it do?
- it allows us to find out the mole ratio in an equation
- mole ration tells us the ratio of the molecules or moles in a substance
- the numbers in the ratio = the numbers in front of the chemicals in a balanced equation

Sample questions that deal with Stoichiometry
1) 3NO₂ + H₂0 --> 2HNO₃ + NO
How many grams of nitrogen dioxide are required in this reaction to produce 5.00 g HNO_3?
ans. 5.48g

2 )CO + 2H₂ --> CH₃OH
If the reaction has 35.4 g of CO and 10.2 g of H₂ how many grams of CH₃OH will be produced?
ans. 40.5

3) 2N₂O₅ --> 4NO₂ + O₂
If a sample of N₂O₅ produces 1.618 g of O₂, how many grams of NO₂ are formed?
ans.9.304g


_{This is a tutorial on dealing with Stoichiometry. Enjoy!}

-Catherine

Enthalpy (Energy Calculations)

When converting from kJ-->mol or mol-->kJ, we use delta H to show us the change in energy.
*Remember sig figs apply to these conversions!

Eg. Calculate the energy  absorbed when 50g of BrCl is formed from Br2 and Cl2
      Br2 + Cl2 + 100 kJ----> 2BrCl
50g x1 mole of BrCl x   100kJ=
         ---------------     --------      21 kJ
          115.4g                2BrCl

When kJ is on the right side, it is an positive, endothermic reaction; when the kJ is on the left, it is an negative, exothermic reaction.


-Victoria


                 

Types of Reactions Continued

            There are 6 types of reactions, and 3 of them have already been covered (synthesis, decomposition, and single replacent). Now, we will look at double replacement, combustion, and neutralization.
  

Double Replacement:
Reaction between two ionic combounds. (AB+CD------> AD+CB)
All ions bond with other ions that they have nota been with yet; then balance the equation.
Eg:  2LiCl + SrO -----> Li₂O + SrCl₂    
Eg:   RbF + CsBr-----> RbBr + CsF

Combustion:
A combustion reaction between organic molecules  and an oxidant. The product will always contain water (H2O and Carbon Dioxide.
Eg: CH4 + 2O2 ----> CO2+ H2O

Neutralization:
A neutralization reaction is when an acid reacts with a base to form a salt. The product will always include H2O. Acids have H in the front, and bases have OH at the end.
Eg: HCl + NaOH---> NaCl+ H2O

* Look at the solubility sheet to see which compounds are soluble or not soluble.
Here is a link to rules of solubility tutorial!
http://www.ausetute.com.au/solrules.html                   
If all  the compounds are aq, there will be no reaction!

Net Ionic Equations:
Ions that are not useful in the reaction are reduced out of the equation.



-Victoria

Endothermic and Exothermic Reactions

 Endothermic Reactions: absorb energy

 Photosynthesis is an example of an endothermic reaction. The chlorophyll and pigments in the plant absorb the light energy from the sun's rays, as endothermic reaction is that in which energy is absorbed.


Exothermic Reactions: release energy to their surroundings
       - Chemical Equation =  reactants à products + energy 

         Explosions are examples of exothermic reactions as they release energy to their surroundings.


- Molecules are held together by chemical bonds

-         add energy to break bonds

-         give off energy to join together

- If a reaction takes more energy to break bonds than it gives off to form bonds à ENDOTHERMIC
- If a reaction takes less energy to break bonds than it gives off to form bonds à EXOTHERMIC

- Enthalpy (H) is the heat contained in a system

Energy Diagrams

-         We can chart the potential energy of the chemicals as they change from reactants to products

-         Reactants start with a certain amount of energy, energy is added to start the reaction and then energy is released as the reaction proceeds.

-         The difference in energy between reactants and products determine whether a reaction is exothermic or endothermic

EXAMPLE 1.

Example 2:

Explanation of Terms:

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

Energy of Products: 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 (reactants to activated complex)
ΔH (change in enthalpy): the change in the potential energy during the reaction. It is the:
                                   energy of the products- energy of the reactants

 Why is this reaction EXOTHERMIC?

The value of ΔH is negative which means energy is given off (shown by the diagram) making this reaction exothermic.

Why is this reaction ENDOTHERMIC?

The value of ΔH is positive which means energy is absorbed making this reaction endothermic.

Energy in the Equation

- Exothermic reactions have energy term on right hand side and a negative ΔH

- Endothermic reactions have the energy term on the left hand side and a positive ΔH

Youtube TIME!!!
http://www.youtube.com/watch?v=XgiCn1IpvzM

Here is a video explaining the differences between exothermic and endothermic reactions.

By Candace

Next class we have a quiz. Here are some practice questions to help you get ready!

Identify the type of reaction taking place.

3AgNO3+K3PO4 -->Ag3PO4+3KNO3

C3H3+5O2-->3CO2+4H2O

Cu(OH)2+2HC2H3O2-->Cu(C2H3O2)2+2H2)

P4+5O2-->2P2O5

8Cu+S8-->8CuS

2NaClO3-->2NaCl+3O2

Ca+2HCl-->CaCl2+H2

2K+2H2O-->2KOH+H2

H2CO3-->H2O+CO2

2C2H2+5O2-->4CO2+2H2O

Ca(C2H3O2)2+Na2CO3+2NaC2H3O2

2C6H14+19O2-->12CO2+14H2O

Balance the following eq'ns:

SO2(g)+HNO3(aq)--> H2SO4(aq)+NO(g)

Al(s)+H2SO4(aq)-->Au(s)+I2(s)

H2O2(aq)+ClO4(aq)--> O2(g)+ClO2(aq)

Br2(aq)+OH(aq)-->O2(g)+ClO2(aq)


Good luck! :)

-Lauren