Finishing up Properties of Water

Tuesday September 11^th

Water will form hydrogen bonds with other substances such as glass, soil and plant tissues. The term for this type of attraction is known as Adhesion

A combination of this and Cohesion can cause water to ‘defy gravity’ by moving UP narrow tubes (such as the roots of trees) in a process known as Capillary Action

**When we added soap to our pennies we were not able to get as much water on them – what do you think the soap did to the water? (Hint:  What causes cohesion)  The hydrogen bonds that hold water to each other are broke apart by the soap.  Because of this, the water is less "cohesive" and has a decreased surface tension.  This fact is why water alone is NOT a good cleaner since it really is just attracted to itself.  Once the hydrogen bonds are broken it is now able to be bond with other molecules to allow better "cleaning" (So wash your hands with water and SOAP otherwise you're not doing much cleaning!!!)

After this we continued through our notes on the properties of water.  You will continue through these tomorrow when I am out and then move into organic chemistry notes on Thursday.  Friday I will discuss all that you write down the two days I will be out.
Monday September 10^th

 *Water can and WANTS to form bonds with how many other water molecules?
4

*Waters attraction to other water molecules is known as Cohesion

*The term for how water “pulls in” at the surface to form a “film” is known asSurface Tension