Chap 2: Environmental Systems Flashcards
Define
Matter
Anything that occupies space and has mass
Define
Mass
A measurement of the amount of matter an object contains
Define
Atom
The smallest particle that can contain the chemical properties of an element
Define
Element
A substance composed of atoms that cannot be broken down into smaller simpler components
Define
Molecule
A particle that contains more than one atom
Define
Compound
a molecule containing more than one element
Define
Hydrogen Bond
a weak chemical bond that forms when hydrogen atoms that are covalently bonded to one atom are attracted to another atom on another molecule
Define
Polar Molecule
A molecule in which one side is more positive and the other side is more negative
Hydrogen bounding makes water molecules stick strongly to one another in an action known as ____.
Hydrogen bonding also makes water molecules stick strongly to certain other substances, an action known as ____.
- cohesion
- adhesion
Name 4 characteristic properties of water that make life on earth possible.
Surface tension
Capillary Action
Boiling and freezing point
Solvent (including capacity to dissolve acid and base)
Structure
Hydrogen bonds makes it possible for water molecule to cohere with one another. Explain why this property make life on Earth (as we know it) possible.
Hydrogen bonds give water it’s characteristic boiling and freezing point. Because of cohesion, water can be a solid, a gas and, more importantly, a liquid at Earth’s surface temperatures.
THe hydrogen bonding between water molecules means that it takes a great deal of energy to change the temerature of water. Theus the water in organisms protects them from wide temperature swings.
Hydrogen bonding also explains why geographic areas near large lakes or oceans have moderate climates.
Liquid water is denser than solid water (ice). Why does it matter for life on Earth (as we know it).
Water occupy a larger volume in it’s solid form, and is therefore less dense, that water in it’s liquid form.
Because ice water is less dense that liquid water, it floats.
If ice was denser than liquid water, lake and ponds would freeze from the bottom up!
Define
Surface Tension
A property of water that results from the cohesion of water molecules at the surface of a body of water and that creates a sort of skin on the water’s surface.
Surface tension also makes water droplets smooth and more or less spherical.
Define
Capillary Action
A property of water that occurs when adhesion of water molecules to a surface is stronger than cohesion between molecules.
The absorption of water by a paper towel or a spnge is the result of capillary action.
This property allows the transport of water up tree trunks and allows for the upward movement of water through soil.
Define
Acid
When an acid is dissolved in water, it realease an hydrogen (H+).
Define
Base
a substance that contributes hydroxide ions (OH-) to a solution.
ex: Household bleach (pH 12) and Seawater (pH 8).
Define
pH
The number that indicates the relative strength of acids and bases in a substance