Chem Class- October 6, 2009

Today in class Mr. D showed us a demonstration. There were two test tubes and each of them had something in them. One of them was white and one of them was purple. Mr. D used the Bunsen burner to heat up the purple one and it turned blue with a bit of moisture. Cool or what?

After that, we went over our homework which was the work sheet for naming compounds. Then we did some notes. Luckily, they weren’t that long!

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More Chemical Nomeclature!

First of all though, we must learn about hydrates.
Hydrates are substances that contain water.
Some compounds can form lattices that bond to water molecules (Eg: Copper Sulfate, Sodium Sulfate).
These crystals contain water inside them which can be released by heating. Without water, the compound is often preceded by Anyhydrous (Eg: Copper (II) Sulphate) just to make it clear that it is not a hydrate.

To name Hydrates:

1. Write the name of the chemical formmula
2. Add a prefix indicating the number of water molecules
    3. Add hydrate after the prefix

Examples: Cu(SO4) . 5H20(s)----->Copper (II) Sulfate Penta Hydrate
                 Nickel (II) Sulfate hexahydrate-----> NiSO4 . 6H2O(s)

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Molecular Compounds

- Composed of two or more non-metals

- Have low melting points and boiling points

- Usually end in -gen or -ine (EG: Hydgrogen, Oxygen and Nitrogen)

- 7 molecules are diatomic (H2, N2, O2, F2,Cl2, Br2, I2) which means that they have two of the same element

- 2 molecules are polyatomic (S8 and P4) which means that they have more than 2 (many) of the same element

Examples

N2O4----->Dinitrogen Tetraoxide

P4O10----->Tetraphosphorous decaoxide

Nitrogen Trichloride----->NCl3

Sulphur Dibromide----->SBr2

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These molecular compounds are very common and have names that don't follow the same rules for naming:

Water is H2O

Hydrogen Peroxide is H2O2

Ammonia is NH3

Glucose is C6H12O6

Sucrose is C12H22O11

Methane is CH4

Propane is C3H8

Octane is C8H8

Methanol is CH3OH

Ethanol is C2H5OH