Factors Affecting Solubility

I'm filling in for Michelle T.

Today was a notes day. We explored how certain conditions, specifically temperature and pressure, impacted the solubility of solutions. Each of these conditions affects their solute differently based on its state of matter; a solid, gas, or liquid.

An increase in temperature for solids and liquids results in an increase of solubility, as the intensified intermolecular motion allows for a more thorough interaction between the solute and solvent. However, higher temperatures in gases results in molecules being released to the atmosphere instead of contained within the solvent, resulting in lower solubility.

Pressure only changes the solubility of gases. Solids and liquids already have their molecules tightly packed so that an increase in pressure would not change the structure of the solute enough to change solubility. Gases are more prone to be altered by pressure because their molecules are more spread out. The increase in pressure forces the molecules of gas down into the solvent, increasing solubility.

We discussed real world examples describing the relationship between pressure and solubility. Soda is kept under high pressure in its can. When that pressure is released when the can is opened, pressure no longer forces the CO2 molecules in to the soda. The CO2 rises to the top in the form of bubbles and thus, carbonation.

Here's some scientific photos to help explain:

BEFORE:

AFTER:

It seems as though a rapid decrease in solubility also has the side-effect of a spontaneous age, gender, and race change.

I guess the next scribe is Michelle T., to fill her duties from today.

The Periodic Table

Today was a notes day... sort of. Between annoying songs and discussions of Nobel prize winners, we did an isotope review sheet and talked about Mendeleev and the Periodic Table. On the review sheet, we filled in missing information about the isotopes given to us and outlined the differences between electrons, protons, and neutrons. The sheet can be found at:

http://gbs-moodle.glenbrook225.org/moodle/file.php/1814/Worksheets_Unit_2/isotopes.doc

and the answers at:

http://gbs-moodle.glenbrook225.org/moodle/file.php/1814/Worksheets_Unit_2/isotopes_answers.pdf

Today's notes contained three major points. First was about the orgin of the periodic table, second was summing up what we learned from the Metals, Non-metals, Metalloids lab, and third was about specific groups on the periodic table. I would put an awesome powerpoint thingy in here, but today's notes aren't on moodle yet so i'll try and get the most important info down for you.

Mendeleev

• Medeleev, Dimitri 1836-1907
• Arranged elements by chemical properties
• Left space for unknown elements at the time
• Predicted properties for unknown elements

Properties of Metals

• Good conductors of heat and electricity
• Shiny
• Ductile
• Malleable
• Reacts with water - corrrodes

Properties of Non-metals

• Poor conductors of heat and electricity
• Not ductile
• Not malleable
• Dull and brittle
• Most are gasses

Properties of Metalloids

• Both Metal and Non-metal properties
• Shiny or dull
• Not as good as Metals at conducting heat and electricity
• Ductile
• Malleable

Periods and Groups

• Periods and horizontal rows
• Groups are vertical columns (1-18)

Alkali Metals

• In the first group
• 1 valence electron
• Shiny
• Clay-like

Alkaline Earth Metals

• In the second group
• Always combined in nature
• 2 valence electrons

Transition Metals

• Groups 3-12
• Good conductors of heat and electricity

Halogen Family

• Group 17
• 7 valence electrons
• Very reactive
• Always combined

Noble Gases

• Group 18
• Outermost energy level is full
• Non-reactive
• Small amounts in atmosphere

Rare Earth Elements

• Lanthanide and Actinide
• Trans-uranium, or man-made

Just in case you wanted to hear it another thirty times, here is the Element Song

The next scribe is Austin W.