February 3, 2010

The Test
People who got less than a 75 on the last test will be able to retake the test sometime next week (either Monday, Wednesday, or Friday), using the book. Dr. B will put your score on this test on the website in addition your previous test, so that it averages out.

The Lab
For the lab tomorrow, you have to do the normal prelab stuff: title, purpose, materials, procedure, data tables, and prelab questions.
You must also draw a grid with all the anions and cations. The cations will occupy the header of the grid, while the anions will occupy the left side of the grid.
You will first drop a cation into each well in the column, followed by the correct anion. After you drop the anion, you will need to make the following observations:
- Color change
- Gas release
- Precipitate
- No reaction

Notes

Definite Melting Point
- Melting is the physical change of a solid to a liquid by the addition of energy as heat
- The temperature at which a solid becomes a liquid is its melting point
- At this temperature, the kinetic energies of the particles within the solid overcome the attractive forces holding them together
- Amorphous solids are sometimes classified as supercooled liquids which are substances that retain certain liquid properties even at temperatures at which they appear to be solid
- These properties exist because the particles in amorphous solids are arranged randomly
High Density and Incompressability
- In general, substances are most dense in the solid state
- The higher density results from the fact that the particles of a solid are more closely packed than those of a liquid or a gas
- For practical purposes, solids can be considered incompressable

Reagents for the Lab
- Sodium phosphate – sodium is soluble, phosphate is an anion
- Potassium hydroxide – potassium is soluble, hydroxide is an anion
- Sodium oxalate – sodium is soluble, oxalate is an anion
- Cobalt chloride – chloride is soluble, cobalt is a cation
- Strontium chloride – chloride is soluble, strontium is a cation
- Potassium iron hexacyanate – potassium is soluble, iron hexacyanate is an anion
- Sodium carbonate – sodium is soluble, carbonate is anion
- Silver nitrate – nitrate is soluble, silver is a cation
- Copper (II) sulfate – sulfate is soluble, copper (II) is a cation
- Nickel (II) chloride – chloride is soluble, nickel (II) is a cation
- Potassium iodide – potassium is soluble, iodide is an anion
- Lead (II) nitrate – nitrate is soluble, lead (II) is a cation
- Iron (III) nitrate – nitrate is soluble, iron (III) is a cation