CHEMISTRY SHENANIGANS

In today's class, we talked about hydrates and molecular compounds, as well as how to name them and the IUPAC formulas.

Hydrates: are compounds that form lattices which bond to water molecules, and the crystals that contain water inside can be released by heating

If a compound does not have water, it is often preceded by "anhydrous" (i.e. copper sulfate anhydrous)

How to name hydrates:

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

ex. Cu(SO₄) · 5H₂O _(s) = copper II sulfate pentahydrate
ex. Nickel II sulfate hexahydrate = Ni(SO₄) · 6H₂O _(s)

The Prefixes in order to name the number of molecules:
Mono =1
Di = 2
Tri = 3
Tetra = 4
Penta =5
Hexa = 6
Hepta = 7
Octa = 8
Nona = 9
Deca = 10



Molecular compounds: are composed of two or more non-metals; they have a low melting point and boiling point; they share electrons; usually end in -gen, or -ine

• Diatomic molecules: (when 2 of the elements are the same) H₂, N₂, O₂, F₂, Br₂, I₂
• Polyatomic molecules: (S₈, P₄)

How to name molecular compounds:

1. Write the formula for the least electronegative ion first, then the formula for the most electronegative ion.
2. Criss-cross the charges, moving the numbers below.
3. Reduce the ion numbers to the lowest common multiples. Note: You do not need to write the subscript '1' or the ionic charges.

When writing a molecular compound back into words, remember to write the prefix in front in front of each element (mono, di, or tri, etc.). You MUST do this for both the first and second part of the compound. However, if there is only one of the first element, you do not write the prefix 'mono'. Also, do not forget to add the ending of 'ide' to the second ion.




Here's an example of a molecular compound. Look closely, and you'll see that the compound is bonded together due to the SHARING of electrons rather than the exchanging of electrons.



In addition, we learned some IUPAC formulas:

IUPAC NAME        FORMULA
Water*                         H₂0
Hydrogen Peroxide*     H₂0₂
Ammonia*                    NH₃
Glucose*                      C₆H₁₂0₆
Sucrose*                      C₁₂H₂₂0₁₁
Methane                       CH₄
Propane                       C₃H₈
Octane                         C₈H₁₈
Methanol                      CH₃0H
Ethanol                         C₂H₅0H

*important formulas to know for tests and future use


Here's a video about gas hydrates, talking about how ice can be used for fuel!