Water Flashcards
Water Lab
What is Cohesion
The tendency of water molecules to stick to each other with aid from Hydrogen bonds.
Trees use it to transport water from roots to top. evaporation pulls it up because of cohesion.
What is surface tension
It shows how difficult it is to break the surface of the water. Hydrogen bonds give it great surface tension. It took a while to overflow the coin and it is related to cohesion.
A water insect uses this property by using long thin feet. It floats on the water film. the hydrogen bonds give strength to let it walk on the water
What is chemical basis of water polarity?
The electrons from the hydrogen atoms spend much more time in the Oxygen atom than in either hydrogen. This causes the hydrogens to get very close. The hydrogen ends of the water is slightly positive while the oxygen is slightly negative.
Polarity allows weak electric attractions called hydrogen bonds between water molecules and causes cohesion. cohesion is important intransporting water to parts of plant
Describe the adhesion of water and other stuff
Water adheres to the glass because the glass is polar so the water molecules often stick to the glass surface. Water does not adhere to the wax because the wax is not polar. therefore the water keeps its shape.
Adhesion and cohesion are important in transporting blood along with water throughpolar capillaries
Describe water’s resistance to temperature change.
Hydrogen bonding resists temperature change in water. A lot of energy is needed to break H bonds first and make water molecules move fast. Water can store a lot of heat and hydrogen bond breakingis little and water molecules don’t move so fast. When water cools more H bonds form, less movement, less heat is kept. While water can lose or gain large amounts of heat, intensity of heat [temperature] is low. Water has less temperature extremes than cooking oil.
As oceans, seas, rivers, and lakes have massive quantities of water, temperature doesn’t rise because of H bonds. This allows marine lif eto exist. Oceans also regulate the tempaerature of coastlines.
THis helps evaporative cooloing. the hot stuff from someone will always evaporate first, and then leave the cold stuff behind. It also cools tropical oceans
Describe water’s abilities as a solvent
water can dissolve in ionic salts and many polar molecules. The water molecules’ negative charged end will combine with the positive end of the ion of the solute.
It cannot dissolve with hydrophobic stuff
The fluids of all organisms are aqueaous. Water can dissolve with enormous variety of stuff necessary for life, such as fluoride
Water is solvent in all cells. It is a medium for many chemical reactions.
Describe Adhesion
tendency of water molecules to stick with other polar surfaces. The the lab, the skinny tube had great surface area, allowing more and more water molecules to stick to the surface.
Adhesion, along with cohesion, helps water molecules travel through the stems and trunks. There are thousands of skinny channels, allowing as much water asap.
What is true of a polar covalent bond
can only occur between atoms of different electrons
Why does water stream change direction in balloon?
because the balloon is negative, the positive H ends of the water molecule are positive, they are attracted to the ballonn.
Describe the Glass and Wax paper
Glass=
amost flat
stuck to the glass
Wax=
very round
the water was stable
Change in Water and Oil?
Water 10 degrees C
Oil 14.8
