Topic 3: Water Flashcards
Which atoms are partially positive when water molecules interact with one another? Which are partially negative? What type of bond form between different water molecules.
Partially Positive: Hydrogen.
Partially Negative: Oxygen
Bond: Hydrogen Bonds
Explain the four properties of life that make it and ideal medium for life. Why?
The four properties of of life are Moderation of Temperature, Ice Floats, Cohesion and Adhesion, and Polar Solvent.
Polar Solvent: Water is polar solvent meaning it dissolves polar substances. And ionic compounds. Partially positive hydrogens attract partially negative oxygen or other molecules. And vice versa.
Ice Floats: As temperature decreases there is not enough energy to break the hydrogen bonds making it less dense and more stable.
Moderation of Temperature:
Water has a high specific heat: requiring more energy to raise the temperature of water.
Water molecules acquire enough energy from other water molecules so surface water molecules can escape and vaporize for the heat of vaporization.
Cohesion: keeps the water molecules together at all times. Allows for surface tension.
Adhesion: attraction between a water molecule and other molecules. Ex. Water can stick to organic tissues of plants.
Explain the relationship between the concentration of hydrogen ions, hydroxide ions and pH.
PH indicates it’s acidity and basicity.
pH tests measure hydrogen ions concentration in a solution.
As pH decrease H+ increased and OH- decreases: More Acidic
As pH increases H+ decreases and OH- increases: More Basic
Calculate pH, H+ or OH-
PH = -log(H+)
(H+)(OH-) =10^-14
Describe the properties of a buffer and explain why they are important in biology.
Buffers consist of a weak acid + it’s base. Can stabilize solutions from changes in pH.
By adding a basic solution. We release hydrogen ions to prevent blood from becoming too basic.
By adding an acidic solution there is a bind to the excess hydrogen ions from the acid to prevent pH from becoming too acidic.
