Solution Chemistry - Mar.30

In today's class we learned about solute, solvents, solubility, saturated and unsaturated solutions.

- Solution Chemistry is the study of chemical reactions in solutions
- A solution is a homogeneous mixture
- Solvents are components present in larger amounts
- Solutes are components present in smaller amounts
- A solute is soluble (dissolves) in a solvent if it dissolves to form a homogeneous mixture
- A saturated solution contains as much solute as possible
- An unsaturated solution can dissolve more solute
- Solubility is the measure of how much solute can dissolve in a given solvent (g/L, g/mL, mol/L, ppm-parts per million)
- The solubility of Ba(NO3)2 in water is 63g/100mL @25 degrees celcius
- The solubility of Ba(NO)2 in alcohol is 1.6g/100mL @25 degrees celcius
- Effects: heat, change of solute/solvent

Example of a Saturated Solution: Water bottle with plain water
Example of an Unsaturated Solution

Atoms and Ions march 22,2010

Atoms and Ions

• Atoms are electrically neutral
• # of protons = #of electrons
• Ions have different # of protons and electrons
• Ions can be either positive (lost e-) or negative (gained e-)
• Cations = positive ion
• Anions = negative ion

Examples

• Determine how many electrons each of the ions have. What type of ion are they (cation/Anion)

Ca2+ -> lost 2e-, 18 electrons, cation

F- -> gained 1 e-, 8 electrons, anion

H+ -> lost 1e-, 0 electrons, cation

H- -> gained 1 e-, 2 electrons, anion

Examples

76 As 3- -> 33 p+, 43 n, 36 electrons (gained 3)

201 Au+ -> 79p+, 122n, 78 electrons (lost 1)

Bohr diagrams for Ions

Bohr diagrams could also be written as:

8e-
2e- 2e-
10 4
9 F 3 Li

Chemical Bonds

• A bond is an electrostatic attraction btwn particles
• Bonds occur as elements try to achieve Noble gas electron configuration
• Noble gases (usually) do not form compunds or bonds
• In Noble gases the outermost energy level have stable octets.
• Metals lose electrons (oxidize)
• Non metals gain electrons (reduced)

Lewis Dot Structure

• Atoms can be represented by dot diagrams
• Dots represent electrons
• Only Vanlence level electrons are shown
• Wtrite the atomic symbol for the atom
• -this rep. the nucleus and filled inner electron leves
• one dot is used to rep outer energy level electrons
• one e- is placed in each orbital before any pairing occurs
• - beginning with the 5th e-, pairing can occur up to a maximum of 8e-

Example

Carbon, Hydrogen, Nitrogen

Ionic Bonds (have brackets (covalent dont have brackets)

• electrons are transferred from metal to nonmental. no dots are shown on metal
• charged species is written in brackets
  

EMISSION SPECTRA - MARCH 5 CLAASS

Emission Spectra

• Each element gives of a specific colour of light
• These are known as emission spectra -Unique to each element
• If electrons absorb energy they can be bumped to a higher level
• When they fall to a lower level, they release that energy as light.
  

Atomic Structure

• Atoms are made up parts called subatomic particles
• Protons(+)
• Neutrons(neutral)
• Electrons(-)

Particle (Multiples of Proton) (Elementary Charges) Location

Mass Charge

Proton 1 1+ Nucleus

Neutron 1 0 Nucleus

Electron 1/1837 -1 Outside

Atomic Number -Number of protons

Isotopes

• The number of protons determine the type of element
• Changing the number of neutrons changes the isotope of the element.
• All isotopes have the same chemical properties

1 proton = protium

1 proton and 1 neutron = deuterium

1 proton and 2 neutrons = tritium

Mass Number

• Mass Number = total of protons and neutrons
• Symbol given is A
• Different Isotopes have different masses

Bohr Model - March 3 Class

- Atoms are electrically neutral
- Two different models can be used to describe electron configuration: Energy level model and Bohr model
- Electrons occupy or orbitals:

1. 2e in the first orbital
2. 8e in the second orbital
3. 8e in the third orbital
   All of these orbitals combined are called an octet

Orbital Shapes:
- Atomic orbitals each have a specific name and shape.


Hybridized Orbitals:
- The first of the Bohr levels is the 1s-orbital and it holds 2e-
- The second level contains 2s, 2px, 2py, 2pz orbitals. They combine (hybridize) to form 2sp3 orbital