1. Elements, Compounds, and Chemical Changes

2. Separation ___________________ How can you separate these solutions??
Milk (proteins are suspended in solution)
Blood (cells and proteins are suspended in solution)
___________________
Yields two layers (solution on top, suspensions on bottom)

3. Density Review: Mass- How much matter is contained in an object
Volume- How much space an object takes up
Density- ??

4. Density Derivation
If density is the amount of matter per unit of volume, then what is the equation to calculate density?
Equation  __________________________
How much space will a 54.8 g sample of Fe occupy if the density is 7.86 g/mL
Note: g/mL = g/cm3 = g*mL-1 = g*cm3-1

5. Graphical Analysis Volume on the x-axis, Mass on the y-axis
As the volume increases for a given substance, so does the mass, at a constant rate.
The slope of this line is the DENSITY!!
We can determine the identity of an unknown substance using its density.

6. Atoms are the Fundamental Components of Elements
The Periodic Table contains a relatively small number of atoms that form an unlimited number of different materials.
This is based on how they combine or bond together

7. Atoms are the Fundamental Components of Elements
The Periodic Table contains a relatively small number of atoms that form an unlimited number of different materials.
This is based on how they combine or bond together
Element – Any material consisting of only one type of atom.
Atom – Submicroscopic particles in a sample. Each element is designated by a symbol (Atomic Symbol)
Co =/= CO, only the first letter is capital

8. Atoms are the Fundamental Components of Elements
Elemental Formula – How many atoms are bonded together in an element
Au = Gold ii. N2 = Nitrogen iii. Ni = Nickel
Seven Diatomic Elements:
Oxygen, Hydrogen, Nitrogen, Bromine, Chlorine, Iodine, Fluorine
How about diatomic oxygen vs. ozone, O3?
Are they the same?
No, BUT both are elemental forms of oxygen

9. Combining Elements to Form Compounds
Molecule- Consists of two or more atoms combined in a definite ratio
Compound– Atoms of different elements bound to one another
We had an Elemental Formula for elements, how will we represent chemicals bound together to form chemical compounds?

10. Combining Elements to Form Compounds
We had an Elemental Formula for elements, how will we represent chemicals bound together to form chemical compounds?
Chemical Formula – How much of what is in the compound (symbols and subscripts)
NaCl: One sodium per chlorine atom
MgCl2: One magnesium per two chlorine atoms

11. Combining Elements to Form Compounds
Hydrogen Sulfide is one of the smelliest compounds. Rotten eggs get their characteristic bad smell from the hydrogen sulfide that they release. Can you infer from this information that elemental sulfur is just as smelly?
*Compounds have Physical and Chemical properties that are different from the properties of their elemental compounds

12. Chemical Changes (rxn)
Remember, a change is chemical ONLY when the BONDS are BROKEN and reformed.
This process creates entirely new substances called ________________.
This change is NOT physical because you CANNOT GO BACK!! 

13. Chemical Changes
Compounds (several DIFFERENT elements together) can be broken down CHEMICALLY to their ELEMENTAL forms
Elemental forms are those consisting of ONLY one type of element
Ex: H2O  O2 + H2 (new elemental PRODUCTS were created)

14. Homework
Page 47-48, #32, 33, 34, 35, 37, 44, 45, 46
Please do on a separate sheet and be ready to turn in for a grade (must have the assignment written on the top line and be neat!!)