Nomenclature (Zac)

Naming Compounds
-Today the most common system is IUPAC for most chemicals (eg. Ions, Binary Ionic, Molecular Compounds, Hydrates, Acids/Bases
-Be aware of the differences between ions and compound formulas
Zn2+ =ion charge,  BaCl2 = # of ions
Multivalent Ions
-Some elements can form more than one ion (eg. Iron has a +3 and +2 charge, Copper has a +2 and +1 charge)
-The top number on the periodic table is more commonly used
-IUPAC uses roman numerals in parentheses to show the charge (eg copper II sulphide)
-Classical systems use latin names of elements and the suffixs -ic (larger charge) and -ous (smaller charge)
Complex Ions
-Complex ions are large groups of atoms that stay together during a chemical reaction
-Almost all are anions (negative) (eg. NaNO3, FeSO3)
Hydrates
-Some compounds can form lattices that bond to water molecules (eg. Cu(SO4) * 5H20(s) = Copper(II) Sulphate Pentahydrate)
-To name hydrates, write the name of the chemical formula, add a prefix indicating the number of water molecules (eg. mono, di, tri... etc), add hydrate after the prefix
Naming Acids & Bases
-Hydrogen compounds are acids
-HCl (aq) - Hydrochloric Acid
-H2SO4(aq) - Sulfuric Acid
- Hydrogen appears first in the formula unless it is part of a polyatomic group
(eg. CH3 COOH(aq) - Acetic Acid)

November 18, 2010: Mole Conversions

Converting Between Moles and Mass:
- To convert between moles and mass we use molar mass as the conversion factor
- Be sure to cancel the appropriate units.
Example 1: How many grams are there in 1.5 mol of H2?

Step 1: 1.5 mol. x [(2(1.0 g.)) / (1 mol.)] = ?
Step 2: 1.5 mol. x [(2 g.) / (1 mol.)] = ?
Step 3: 1.5 mol. x [(2 g.) / (1 mol.)] = 3 g.

There are 3 grams of H2 in 1.5 moles.

Example 2: A sample of HCl contains 0.72 mol. How many grams of HCl are there?

Step 1: 0.72 mol. x [(1(1.0 g.)) / (1 mol.)] = ?
Step 2: 0.72 mol. x [(35.5 g.) / (1 mol..)] = ?
Step 3: 0.72 mol. x [(35.5 g.) / (1 mol.)] = 26 g.

There are 26 grams of HCL in 0.72 mol.

Example 3: How many moles are there in 110 grams of Fe2O3?

Step 1: 110 g. x [(1 mol.) / (2(55.8 g.) + 3(16.0 g.)] = ?
Step 2: 110 g. x [(1 mol.) / (159.6 g.)] = ?
Step 3: 110 g. x [(1 mol.) / (159.6 g.)] = 0.689 mol.

In 110 grams of Fe2O3 there is 0.689 mol.

November 18, 2010: Molar Mass (Angelo)

Mass of Atoms:
- The mass (in grams) of 1 mole of a substance is the molar mass
- It can be determined from the atomic mass on the periodic table measured in grams per mole (g/mol).
Example:
What is the mass of Copper (Cu)?
63.5 grams  

Molar Mass of Compounds:
- To determine the molar mass of a compound, add the mass of all the atoms together.
Example: 
What is the molar mass of H2O? 
Write out the the mass of each atom and multiply that by its frequency in the compound and calculate: 2(1.0 g) + 1(16.0 g) = 18.0 g/mol.

NOTE: Because we are adding instead of multiplying or dividing figures, we round our final answer to the highest number of significant digits in our equation.

November 5, 2010: Hydrate Lab (Angelo)

Hydrate Lab:

Discussion:
Hydrates are ionic compounds that contain an inorganic salt compound loosely bound to water. The purpose of this experiment is to determine the empirical formula of a hydrate. Examples are: magnesium sulfate heptahydrate (epsom salts) and sodium carbonate decahydrate (washing soda). The formulas for substances are MgSO4*7H2O and Na2Co3*10H2O. They can also be represented as MgSO4(H2O)7 and Na2CO3(H2O)10. In this lab you will be dtermining the anhydrous (without water) mass of the hydrate. You will compare this with the actual mass of water that should be present.

Materials:
- Bunsen burner
- Test tube
- Test tube rack
- Test tube clamp
- Weight scale
- Cobaltous chloride hexahydrate

Procedure:
1. Fill a test tube about 1 cm. with the hydrate.
2. Carefully place the test tube on the scale and record the mass of the hydrate and test tube.
3. Using extreme caution, connect andl ight your Bunsen burner. Adjust the gas flow until the flame is about five cm. tall.
4. Pick up the test tube with the clamps and carefully hold it in above the Bunsen burner.
5. Gently heat the test tube by moving the test tube in and out of the flame for about 5 minutes or until all the water has boiled away.
6. Carefully re-weight the test tube ensuring none of the chemicals inside spill.

Observation:
Test Tube Weight - 18.78 grams
Mass Before Heating - 19.38 grams
Mass After Heating - 19.09 grams

Analysis:
1. Determine how much water was released during the heating? 0.29 grams
2. What percent of the hydrate was water? 48%

Conclusion:
1. The actual percent water in this hydrate is 45%. Determine your percent error for part 2.
Write out the formula: [(measured - accepted) / (accepted)] x 100 
Plug in the numbers: [(48% - 45%) / (45%)] x 100
Calculate: 6.7%

In this lab conducted, the percent error was 6.7 percent.

October 28th,2012:Trends on the Periodic table(Brian)

Elements close to each other on the periodic table display similar characteristics.
The are 7 important trends:
1) Reactivity
     - metals and non metals show different trends 
     - the most reactive metal is Francium and the most reactive non-metal is Fluorine
2) Ion Charge
     - an elements ion charge depends on their group(column)
3) Melting Point
     - elements in the center of the table have the highest melting points
     - Noble gases have the lowest melting points
     - starting from the left and moving right, melting points increase(until the middle of the table)
4) Atomic Radius
     - the radius decreases going up and right on the table
     - Helium has the snallest atomic radius and Francium has the largest atomic radius
5) Ionization Energy
     - is energy needed to completely remove an electron from an atom
     - it increases going up and right
     - all noble gases have high ionization energy
     - Helium has the highest and Francium has the lowest
     - opposite trend of the Atomic Radius
6) Electronegativity      - refers to how much an atom wants to gain electrons
     - same trend as ionization energy
7) Density