AP Bio Chapters 2 and 3 Flashcards
Knowing just the atomic mass of an element allows inferences about what?
The number of protons plus neutrons in the element
About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?
Carbon, hydrogen, nitrogen, oxygen
Carbon-12 is the most common isotope of carbon, and has an atomic mass of 12 daltons. A mole of carbon in naturally occurring coal, however, weighs slightly more than 12 grams. Why?
Some carbon atoms in nature have more neutrons
From its atomic number of 15, it is possible to predict that the phosphorus atom has
15 protons and 15 electrons
A covalent chemical bond is one in which
Outer-shell electrons of 2 atoms are shared so as to satisfactorily fill the outer electron shells of both atoms.
What results from an unequal sharing of electrons between atoms?
A polar covalent bond
What is the difference between covalent bonds and ionic bonds?
Covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between atoms
Van der Waals interactions result when
Electrons are not symmetrically distributed in a molecule.
Not considered to be a weak molecular interaction
A covalent bond
In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by
Polar covalent bonds
The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called?
Hydrogen bond
Effect produced by the high surface tension of water
A water strider can glide across the surface of a small pond
Liquid water’s high specific heat is mainly a consequence of what?
Absorption and release of heat when hydrogen bonds break and form.
Why does ice float in liquid water?
Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water
