Biology 1 Chapter 3 (Lecture) Flashcards
What is the only common substance to exist in the natural environment that exist in all 3 physical states of matter?
Water
What is the major reason Earth is inhabitable?
Abundance of water.
Cells are ____ water?
70-95%
What does it mean that water is a polar molecule?
The 2 ends of the molecule have opposite charges; oxygen region has partial negative, and the hydrogen regions have partial positive.
Hydrogen Bonds
Bond between water molecules
IMPORTANT QUALITY OF WATER
The H bonds are fragile & are breaking and reforming.
Ability to moderate ______ due to having high specific heat and evaporative cooling
Temperature.
Water expands upon
Freezing
Water is a
Solvent
Heat
Total kinetic energy due to motion of its molecules
Temperature
Measure of heat intensity that represents the average kinetic energy of the molecules.
Ice Cube
Not by adding cold by absorbing heat.
Water Freezes
0 C
Water Boils
100 C
Human Body
37 C
Room Temp
20-25 C
Why does evaporative cooling occur?
as a liquid evaporates the surface of the liquid that remains behind cools down. (Stability of temp)
When water freezes
is less dense (ice floats, forming a barrier in lakes and ponds)
The dissociation of water yields the __ ion and the __ ion
H+ and OH-
pH scale
Describes how acidic and basic a solution is. (0-14)
The product of the [H+] times the [OH-] is
10 ^ -14
Neutral Solution
10^-7
pH=
-log[H+]
Substances that minimize changes in the concentrations of H+ ions and OH- ions.
Buffers
Acid
A substance that increases the H+ concentration of a solution; pH below 7
Solvent
The dissolving agent of a solution
Solute
The substance that is dissolved in a solution
Mole
The amount of mass of a substance that contains 6.023 X 10^23 molecules of that substance.
Polar Molecule
Molecule that has an uneven distribution of charges
Surface Tension
Measure of how difficult it is to stretch or break the surface of a liquid
Cohesion
Attraction of water molecules to other water molecules and held by hydrogen bonds.
Specific Heat
Amount of heat that must be absorbed or lost to change the temp of 1 gram of a substance 1 degree C
Hydrophilic
Substance that has an affinity for water
Hydrophobic
Substance that repels water
Adhesion
Attraction between different substances
Occur because of a change of the molecules with greatest kinetic energy changing from liquid to gas
Evaporative Cooling
pH of blood
7.4
Property of water that tends to stabilize the ocean temp.
High Specific Heat
Property of water that helps to moderate earth’s climate
High Heat of Vaporization
Determines the cohesiveness of water molecules
Hydrogen bonds.
