R-AECHE-32

Graph

Solubility Curves:

Solubility curves show the solubility of substances as temperature changes.
Generally, the solubility of ionic solids increases with temperature. This is because there is more energy to overcome bonding in the solid.

Chromatography:

An analytical technique
Graphite does not dissolve in aqueous or organic solvents. Therefore, we use graphite as the material of our line of origin in paper chromatography.
Do not add any extra variables, time between chromatograms should be constant.
2 Principles:
- Capillary action still draws the solvent up the matrix, however while the molecules in paper chromatography are separated based on mass, in TLC, separation often depends upon solubility or charge, due to the interaction of solute and matrix.
- A dry sample is played in the silica gel matrix. As the solvent front moves up the gel, it dissolves the sample and carries it up the matrix with it.
Many substances are white or colourless, and so aren't visible on a TLC plate.
One way of making colourless substances show up is to use UV light.
This usually works well for organic compounds.
A chemical locating agent can be used.
Ninhydrin is a common one. When reacted with an organic compound, it stains it purple-brown.
The solvent is drawn up the stationary phase by capillary action.
- Adhesive force are between molecule of different substance. Adhesion enables solvent molecules to bond to stationary phase.
- Cohesive forces are between molecules of the same substances. Cohesion enables solvent molecules to bond each other, and move each other through stationary phase.

The most crucial information to year 11 chemistry

When you stay quiet, zombie cannot see you
When you have a terminal illness, zombie cannot see you because you are not a good host
How did Jerusalem got sieged by zombies
- Jerusalem people started singing
- Zombie was like "hang on a minute what's happening" - actual quote from Ms Pilling
- Zombie started building a zombie ladder
- One by one they got to the top of the wall
- Story is that zombies infected Jerusalem.
- Ukrainian plane die before reaching Ukraine
Attraction of zombie to all is called adhesive forces
- The force is between different types of things: Zombie and wall
- Cohesive force is the attraction between zombies

This was indeed said by Ms Pilling.

Capillary action:

The mobile phase (solvent) is drawn up the stationary phase by capillary action.
Adhesive forces are between molecules of different substances. Adhesion enables solvent molecules to bond to the stationary phase.
Cohesive forces are between molecules of the same substance.

TLC Advantages:

The glass plate is rigid, not flexible like paper, so it is easy to control.
After separation, the substances in the mixture can be recovered. The silica gel holding the separated substance is scraped off the glass plate and added to a solvent. The substance will dissolve and the silica gel can easily be removed by filtration. The glass plates can be recoated with silica gel and used over and over again.