Chp 2 Flashcards
Surface Tension
a measure of how difficult it is to stretch or break the surface of a liquid
Heat Vaporization
the quantity of heat a liquid must absorb for 1 gram of it to be converted from the liquid to the gaseous state
Adhesion
the clinging of one substance to another
Evaporative cooling
the cooling of a liquid’s surface as some of the liquid evaporates
Ionic bonds form as a result of
the attraction between ions that have opposite charges.
Equal Sharing of electrons occurs in a
Covalent bond
Unequal sharing of electrons occurs in a
polar covalent bond
A hydrogen bond is formed as a result of
the noncovalent attraction between a hydrogen atom and an atom with a partial negative charge.
Van der Waals interactions involve
chance accumulations of electrons as they move around atomic nuclei.
A molecule consisting of two atoms, such as hydrogen gas (H2) or oxygen (O2) is
always linear
Molecules containing many carbon atoms, such as glucose (C6H12O6)
have more complex shapes than that of a completed tetrahedron.
Which main molecules have a tetrahedral shape
methane, CH4, ammonia, NH3, and water, H2O
more carbon dioxide causes
an increase in carbonic acid (H2CO3),
A covalent bond will be polar if
one of the atoms sharing electrons is more electronegative
An acid is
a substance that donates hydrogen ions to a solution
Bases
accept hydrogen ions. Bases thereby decrease the hydrogen ion concentration of solutions.
Basic Solutions
have a pH between 7 and 14
A buffer is a substance that
minimizes changes in the concentrations of H+ and OH− in a solution and therefore resists changes in pH. t does so by accepting hydrogen ions from the solution when they are in excess and donating hydrogen ions to the solution when they have been depleted.
The chemical characteristics or reactivity of an element depend mostly on
the number of electrons in its outermost shell.
When the number of protons and electrons possessed by an atom are unequal, the atom
is an ion
An atom that normally has_______in its outer shell would not form chemical bonds with other atoms.
eight electrons
Cells are surrounded by water, and cells themselves consist of about 70 to 95 percent water. As a result,
the temperature of living things tends to change relatively slowly
a variety of nutrient molecules is readily available as dissolved solutes
waste products produced by cell metabolism can be easily removed
dissolved substances can be easily transported within a cell or between cells in multicellular organisms
Coastal climates are more moderate than inland climates primarily because of water’s high __________.
specific heat
The tendency of water molecules to stay close to each other as a result of hydrogen bonding __________.
acts to moderate temperature
provides the surface tension that allows leaves to float on water
is called cohesion
keeps water moving through the vessels in a tree trunk
Sweating has a cooling effect because of water’s high
heat of vaporization.
Hydrophilic substances
have charges or partial charges to which water molecules can adhere
A solution at pH 6 contains____than the same amount of solution at pH 8.
100 times more H+
The amount of heat required to change the temperature of 1 g of a substance by 1°C is defined as .
the specific heat of that substance
Adhesion is best described as .
the clinging of one substance to another substance
