Title says all...is it worth buying notes/essays from others? Or should I make my own notes? I find it hard making notes because their is so much "stuff" that seems important and you just keep putting them on the syllabus dot-points/expanding your notes even more, which is going to be hard to remember ==''. I will give you an example of what i did today...
• Choose equipment and perform first – hand investigations to demonstrate the following properties of water:
- Surface tension
- Viscosity
Expected result:
Water forms rounded droplets on clean glass and wax whereas the other liquids do not.
Detergent lowers the surface tension of water and so it forms a film rather than droplets.
Hexane flows faster than water or ethanol as it has a much lower viscosity.
Summary:
• High viscosity = Flows more slowly
• The water droplets would be well rounded and stand high above the glass surface.
• The dilute detergent solution would form a film on the glass rather than a drop.
• The detergent lowers the surface tension of the water and the drop is correspondingly flatter.
• The presence of the detergent (a surfactant) interferes with the hydrogen bonds that hold the surface of water molecules tightly together.
• The adhesive forces between the glass and the detergent solution are now stronger and the detergent solution spreads out over the glass surface.
• Surface tension decreases as the temperature increases.
- At the higher temperature the molecules of water have greater kinetic energies.
- This greater molecular motion acts against the formation of hydrogen bonds.
- The water molecules move slightly further apart, so the attractive forces between molecules decrease.
(not complete yet btw)
so...what do you think?
• Choose equipment and perform first – hand investigations to demonstrate the following properties of water:
- Surface tension
- Viscosity
Expected result:
Water forms rounded droplets on clean glass and wax whereas the other liquids do not.
Detergent lowers the surface tension of water and so it forms a film rather than droplets.
Hexane flows faster than water or ethanol as it has a much lower viscosity.
Summary:
• High viscosity = Flows more slowly
• The water droplets would be well rounded and stand high above the glass surface.
• The dilute detergent solution would form a film on the glass rather than a drop.
• The detergent lowers the surface tension of the water and the drop is correspondingly flatter.
• The presence of the detergent (a surfactant) interferes with the hydrogen bonds that hold the surface of water molecules tightly together.
• The adhesive forces between the glass and the detergent solution are now stronger and the detergent solution spreads out over the glass surface.
• Surface tension decreases as the temperature increases.
- At the higher temperature the molecules of water have greater kinetic energies.
- This greater molecular motion acts against the formation of hydrogen bonds.
- The water molecules move slightly further apart, so the attractive forces between molecules decrease.
(not complete yet btw)
so...what do you think?