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53 terms

bio101

water
STUDY
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The unequal sharing of electrons within a water molecule makes the water molecule _____.
polar
The tendency of an atom to pull electrons toward itself is referred to as its _____.
electronegativity
what type of bond is found between the oxygen and hydrogens in water?
polar covalent
Water is moving up the tree as it ______ from the leaf surface.
evaporates
Water molecules cling to the side of a beaker. This is an example of?
adhesion
Water molecules are attracted to each other. This is an example of?
cohesion
A needle floats when it is placed gently on top of water in a bucket. This is an example of?
surface tension
Water molecules cling to plant cell walls. This is an example of?
adhesion
A drop of water spilled on a table form a drop on the table, rather than spreading out on the surface. This is an example of?
cohesion
A water strider runs across a pond without breaking the surface. This is an example of?
surface tension
In a neutral solution the concentration of hydrogen ions is equal to the concentration of _____?
hydroxide ions
A water molecule that gains a hydrogen becomes a _____?
hydronium ion
A water molecule that loses a hydrogen ion is referred to as a _____?
hydroxide ion
The transfer of a hydrogen atom from one water molecule to another is referred to as _____?
dissociation
What is the charge on a hydronium ion?
1+
What is the charge on a hydroxide ion?
1-
About _____ molecules in a glass of water are dissociated.
1 in 500,000,000
Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
the absorption of heat by the breaking of hydrogen bonds
The bonds that are broken when water vaporizes are?
hydrogen bonds between water molecules.
Measurements show that the pH of a particular lake is 4.0. What is the hydrogen ion concentration of the lake?
10^-4 M
Measurements show that the pH of a particular lake is 4.0. What is the hydroxide ion concentration of the lake?
10^-10 M
Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as _____.
hydrogen bonds
Many of water's emergent properties, such as its cohesion, its high specific heat, and its high heat of vaporization, result from the fact that water molecules _____.
are electrically attracted to each other
The amount of energy that must be absorbed or lost to raise or lower the temperature of 1 g of liquid water by °C _____.
is 1 calorie
Because organisms are made primarily of water, they resist rapid temperature changes. This useful quality is based on water's _________.
high specific heat
Sodas typically contain sugar, flavorings, coloring agents, and carbon dioxide dissolved in water. The best term to describe this mixture would be _____.
an aqueous solution
If the molecular mass of a carbon atom is 12, the mass of a hydrogen atom is 1, and the mass of an oxygen atom is 16 daltons, how many molecules does one mole of sugar (C12H22O11) contain?
6.02 x 10^23
An acid is a substance that _____.
increases the hydrogen ion concentration of an aqueous solution
A pH of 6 is how many times more acidic than a pH of 9?
1,000
A _____ accepts hydrogen ions when they are in excess and donates hydrogen ions when they have been depleted.
buffer
Most acid precipitation results from the combination of ____ with water in the atmosphere, forming strong acids that fall with rain or snow.
sulfur oxides and nitrogen oxides
We can be sure that a mole of table sugar and a mole of vitamin C are equal in their?
number of molecules
List four characteristics of water that are emergent properties resulting from hydrogen bonding.
cohesion/adhesion, moderation of temperature, insulation, universal solvent
Define cohesion.
Hydrogen bonds hold water together
Define adhesion.
the clinging of one substance to another
Define heat.
movement of molecules, faster the movement, heat increases
Define temperature.
measure of heat intensity, average kinetic energy
Coastal climates have milder climates than adjacent inland areas. This is an example of what property of water?
evaporative cooling
Ocean temperatures fluctuate much less than air temperatures on land. This is an example of what property of water?
specific heat
Ice floats on water. This is an example of what property of water?
insulation
Humans sweat and dogs pant to cool themselves on hot days. This is an example of what property of water?
kinetic energy
Define the term solute.
the result of a solvent, h2o + dissolved substance
Define the term solvent.
the dissolving agent of a solution
Define the term solution.
a liquid that is a completely homogeneous mixture of 2 or more substances
Define the term hydrophobic.
does not absorb
Define the term hydrophillic.
absorbs water, loves water
What are the products in the dissociation of water?
hydronium ions (H30+) and hydroxide ions (OH-)
What is the concentration of the products of dissociation in pure water?
at 25 degrees C = 1x10^-7 M each
Define the term acid.
a substance that increases the hydrogen ion concentration of a solution
Define the term base.
a substance that increases the hydroxide ion concentration of a solution
Define the term pH.
the negative logarithm (base 10) of the hydrogen ion (H+) concentration of a solution
How do acids and bases alter the hydrogen ion concentration of a solution?
Adding H+ will make a solution more acidic. Decreasing H+ will make a solution more basic.
How do buffers work? Use the bicarbonate buffer system to explain.
1. Carbonic acid and bicarbonate act as a pH regulator. 2. If H+ is depleted (pH rises) more carbonic acid dissociates. 3. If H+ is in excess the bicarbonate acts as a base. 4. Removes excess H+ ions.