Presentation on theme: "Aqueous Information for you. covers about three fourths of the surface of the makes up from 50 to 95 percent of the weight of living organisms cytoplasm."— Presentation transcript:
covers about three fourths of the surface of the makes up from 50 to 95 percent of the weight of living organisms cytoplasm of a cell is a water-based solution (an aqueous solution) It's in the air we breathe Water has special properties BP of water is 212 o F, 100 o C; Freezing point is 32 o F, 0 o C it remains liquid at much higher temperatures than expected, and freezes at too low a temperature for its size---WHY????liquid
cohesion : water molecules are attracted to each other like small magnets cohesion This is caused by the structure of the H 2 O molecule: Hydrogen does not share its electrons equally with the oxygen atoms in the molecule, oxygen is a hog! This results in the oxygen continually having a slight negative charge because of the extra electrons it is hogging. Meanwhile the hydrogens having the electrons so seldomly, tend to have a positve charge because of their positive proton that has no negative electron to balance it. THIS IS CALLED POLARITY -different ends of the molecule have slightly opposite charges
The cohesion of water is due to hydrogen bonding, which is the weak attraction of the slightly positively charged side of a molecule containing Hydrogen with a negative portion of another molecule.hydrogen bonding hydrogen is always pretty wimpy and allows atoms to hog its electrons frequently! Hydrogen bonds are weaker than covalent bonds or ionic bonds and can be severed fairly easily
Not all molecules are polar, if no slight charges are present, the molecule is called non-polar If one portion of a large molecule has a slight charge but the other side of the molecule remains uncharged, the molecule is called amphipathic. Like molecules stick together, polar and non- polar molecules will not mix well, Polar molecules mix easily with other polar molecules, like water and salt. Can you think of something that does not mix well with water?
Hydro means water phobo means hate or fear phillos mans love Salad oil is a hydrophobic substance All polar substances are hydrophilic. What do these words mean???
Hydrophilic substances will exhibit the property of adhesion, an attraction to water. An adhesive substance will pull on the waters cohesiveness. Sometimes destroying the natural droplets that form due to waters attraction to itself. What is the difference between cohesion and adhesion?
Capillary action occurs due to cohesion and adhesion. We see it when water travels up a small tube made of an adhesive substance like glass. The water is attracted to the inside of the glass tube (adhesion due to hydrogen bonds) The water begins to travel up the glass tube, pulling more water behind it due to cohesion. The water travels up the tube, even against gravity due to the pull of the hydrogen bonding occurring between the water and glass tube and the water and itself.
How does water rise from the roots of a redwood tree to the very top? How do insects walk on water? Why does ice float rather than sink?