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Chemistry
water molecules
54
Chemistry
10th Grade
03/10/2011

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Term
A water molecule is a simple_____molecule and it is also_____.
Definition
triatomic; polar
Term
What prevents most liquid water molecules from escaping the surface of the liquid?
Definition
hydrogen bonding
Term
What are five properties of the water molecule?
Definition
high surface tension, low vapor pressure, high specific heat capacity, high heat of vaporization, and high boiling point
Term
Water surface acts as a _____.
Definition
skin-surface tension
Term
The inward force that minimizes surface area of a liquid is called_____.
Definition
surface tension
Term
Surface tesnion holds water in a _____shape.
Definition
spherical
Term
How can surface tension be decreased? What does this interfere with?
Definition
by adding surfactant; hydrogen bonding
Term
What is vapor pressure caused by?
Definition
molecules escaping liquid
Term
What type of systems are heterogeneous mixtures? what types are homogeneous?
Definition
colloids and suspensions; solutions
Term
In a suspension, are the particles bigger or smaller than the particles in a solution?
Definition
bigger
Term
How does the size of teh particles in colloids compare to those of suspensions and true solutions?
Definition
they are intermediate in size
Term
The dispersion can be____,_____,or____.
Definition
solid, liquid, or gas
Term
What are two examples of a colloid?
Definition
smoke and glue
Term
When concentrated, colloids can appear_____or_____. When very dilute they are almost_____.
Definition
milky or cloudy; clear
Term
What is the tyndall effect?
Definition
the scattering of visible light in all directions
Term
What two types of systems exhibit the tyndall effect?
Definition
colloids and suspensions
Term
What is the brownian motion?
Definition
chatoic movement of colloidal particles
Term
What causes the brownian motion?
Definition
the collisions of the water molecules of the medium with the small, dispersed colloidal particles
Term
All the particles in a particular colloidal system have the same_____.
Definition
charge
Term
What must happen to hydrogen bonds before water changes from liquid to vapor?
Definition
they must be broken
Term
What does water's high heat of vaporization help to accomplish?
Definition
helps moderate temperature in the tropic and polar regions
Term
As water cools does it become more or less dense?
Definition
more
Term
Below 4 degrees celsius, water becomes more or less dense?
Definition
less
Term
Why does ice float?
Definition
becasue ice is less dense than liquid water at zero degress celsius
Term
What structure do the water molecules in ice make?
Definition
 a honeycomb
Term
Which is more closely packed: ice or liquid water?
Definition
liquid water
Term
Because ice floats, ice _____water below it and it keeps water at the bottom above what temperature?
Definition
insultates; zero degrees celsius
Term
What is an aqueous solution?
Definition
water containing dissolved substances
Term
What is the solvent? What is the sollute?
Definition
dissolving medium; dissolved particles
Term
Solute particles can be ____or_____.
Definition
ionic or molecular
Term
_____is the process that occurs when a solute dissolves.
Definition
solvation
Term
What surrounds the solute particles?
Definition
solvent molecules
Term
______are compounds that conduct electric current in aqueous solutions or in the molten state.
Definition
electrolytes
Term
______are compounds that do no conduct electric current in aqueous solution or the molten state.
Definition
nonelectrolytes
Term
_____is a solution in which only a fraction of the solute exists as ions.
Definition
weak electrolyte
Term
______is when almost all the solute exists as separate ions.
Definition
strong electrolyte
Term
What is water of hydration?
Definition
when water is chemically combined in crysal
Term
What is a hydrate?
Definition
compound that contains water of hydration
Term
What happens to a hydrate when it's heated?
Definition
it loses the water
Term
Are the forces holding the water molecules in together in hydrate strong or not strong?
Definition
not strong
Term
What does it mean when a hydrate effloresces?
Definition
it loses water to the air
Term
What does it mean when a hydrate is hygroscopic?
Definition
compounds remove moisture from the air
Term
What is a synonym for hygroscopic?
Definition
desiccants
Term
What does it mean when a hydrate is deliquescent?
Definition
compounds absorb so much water from the air that they dissolve completely and form solutions
Term
_____are electrolytes when melted or dissoled in water.
Definition
ionic compounds
Term
Do solutions exhibit the tyndall effect?
Definition
no
Term
Do particles in a colloid settle out over time?
Definition
no
Term
Will ethanol, a polar comound dissolve in water?
Definition
yes
Term
The attractions between adjacent water molecules are called_____.
Definition
hydrogen bonds
Term
The attractions between adjacent water atoms are called ______.
Definition
covalent bonds
Term
What two types of systems exhibit the tyndall effect?
Definition
colloids and suspensions
Term
Non polar compounds dissolve in _____.
Definition
nonpolar solvents
Term
What types of cpounds dissolve in water?
Definition
polar compounds because water is polar
Term
What type of compounds are polar? What types are nonpolar?
Definition
ionic are polar; molecular are nonpolar
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