___________________________________ make(s) up the nucleus of an atom.
Protons and electrons
Protons and neutrons
DNA and RNA
Neutrons and electrons
DNA only
Living organisms are composed mainly of which atoms?
calcium, hydrogen, nitrogen, and oxygen
carbon, hydrogen, nitrogen, and oxygen
hydrogen, nitrogen, oxygen, and helium
carbon, helium, nitrogen, and oxygen
carbon, calcium, hydrogen, and oxygen
The ability of an atom to attract electrons in a bond with another atom is termed its
hydrophobicity
electronegativity
solubility
valence
both a and b
Hydrogen bonds differ from covalent bonds in that
covalent bonds can form between any type of atom, and hydrogen bonds form only between H and O.
covalent bonds involve sharing of electrons, and hydrogen bonds involve the complete transfer of electrons
covalent bonds result from equal sharing of electrons, but hydrogen bonds involve unequal sharing of electrons.
covalent bonds involve sharing of electrons between atoms, but hydrogen bonds are the result of weak attractions between a hydrogen atom of a polar molecule and an electronegative atom of another polar molecule.
covalent bonds are weak bonds that break easily, but hydrogen ions are strong links between atoms that are not easily broken.
A free radical
is a positively charged ion.
is an atom with one unpaired electron in its outer shell.
is a stable atom that is not bonded to another atom
can cause considerable cellular damage
both b and d.
Chemical reactions in living organisms
require energy to begin
usually require a catalyst to speed up the process
are usually reversible
occur in liquid environments, such as water.
all of the above
Solutes that easily dissolve in water are said to be
hydrophobic
hydrophilic
polar molecules
b and c only
The molecular mass of glucose is about 180 g/mol. If 45g of glucose is dissolved into a final volume of 0.5L of water, what is the molarity of the solution?
0.125M
0.25M
0.5M
1.0M
2.0M
The sum of the atomic masses of all the atoms of a molecule is its
atomic weight
molarity
molecular mass
concentration
polarity
Reactions in which water is used to break apart other molecules are known as ___________________ reactions.
dehydration
anabolic
hydrolysis
