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NORTON BIOLOGY 2020-21 (Section 2.2)

Terms in this set (52)

Water has a ______ negative charge on one end and a partial ______ charge on the other .
partial, positive
A molecule in which the charges are unevenly distributed is said to be _____.
polar (because the molecule is a bit like a magnet with two poles).
The attraction between a hydrogen atom with a partial positive charge and another atom with a partial negative charge is known as a ______ ______.
hydrogen bond
Each molecule of water can form multiple hydrogen bonds with other water molecules is called
hydrogen bonding
Which is weaker, covalent bond, iconic bond, or hydrogen bond?
hydrogen bond
Because water is a polar molecule, it is able to form _______ hydrogen bonds which account for may of water's special properties.
multiple
The attraction between molecules of the same substance is called ____.
cohesion
Water is extremely ______.
cohesive
________ causes water molecules to be drawn together, which is why drops of water form beads on a smooth surface.
cohesion
_______ also produces surface tension which allows some insects and spiders to walk on a pond's surface.
cohesion
The attraction between molecules of different substances is called ___.
adhesion
When water rises in a narrow tube against the force of gravity, this is called ______.
capillary action
______ _____ is one of the forces that draws water out of the roots of a plant and up into its stems and leaves.
capillary action
______ holds the column of water together as it rises.
cohesion
A substances heat capacity is the amount of _______ needed to raise it's temperature by making it's molecules move ________.
energy, faster
Living things are composed mostly of ___.
water
Water accounts for _____ percent of the mass of the human body.
60
Nearly everything that cells do---from growth and development to movement--takes place by means of _____ _____ in a ______ _____.
chemical reaction, water environment
A _____ is a material composed of two or more elements or compounds that are physically mixed together but not chemically combined
mixture
Earth's atmosphere is a mixture of: ____.
nitrogen, oxygen, carbon dioxide, and other gases.
Two types of mixtures that can be made with water are ______ and _____.
solutions and suspensions.
Ions gradually become dispersed in the water, forming a type of mixture called a _______
solution
In a saltwater solution, table salt is the ____.
solute (the substance that is dissolved)
The substance in which the solute dissolves is called _____.
solvent
Water's ________ gives it the ability to dissolve both ionic compounds and other polar molecules
polarity
______ is life's most important solvent.
water
When a given amount of water has dissolved all of the solute it can, the solution is said to be ________.
saturated.
mixtures of water and non dissolved material are known as ____________
suspensions
The blood that circulates through your body is mostly ______.
water
When an iconic compound such as sodium chloride is placed in water, water molecules surround and separate the ______ and ______ ions.
positive, negative
The concentration of H+ ions determines whether solutions are _____ or ____.
acidic, basic
Because the number of positive hydrogen ions produced is equal to the number of ________ hydroxide ions produced, pure water is ______ neutral.
positive, electronically
Chemists have devised a measurement system called the _____ ___ to indicate the concentration of H+ ions in solution.
pH scale
At a pH of 7, the concentration of H+ ions and OH (-) ions is _____.
equal
Solutions with a pH below ___ are called acidic because they have more H+ ions.
7
The lower the pH, the greater the ______.
acidity
The solutions with a pH above 7 are called _____ because they have more OH (-) ions than H+ ions.
basic
The higher the pH, the more ______ the solution.
basic
acid
Any compound that releases hydrogen ions into a solution. Also, a water solution that contains a surplus of hydrogen ions.
base
is a compound that produces hydroxide ions in solution
The internal pH of most cells in the human body must generally be kept between ___ and ___.
6.5, 7.5
Controlling pH is important for maintaining ______.
homeostasis
One of the ways that organisms control pH is through dissolved compounds called _____
buffers
Buffers are _____ acids or bases that can react with _____ acids or bases to prevent sharp, sudden changes in pH.
weak, strong
________ help prevent drastic changes in pH.
buffers
Sudden changes in blood pH are usually prevented by a number of chemical _____ , such as bicarbonate and phosphate ions.
buffers
cohesion
the attraction of like molecules to each other
hydrogen bond
the hydrogen of one water molecule with the oxygen of another
solute
the dissolved substance found in a solution
What happens when a solvent and a solute mix?
A solution.
solvent
a substance that dissolves another substance
suspension
a material that does not mix with water
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