Chapter 2 Flashcards
The Chemical Foundation of Life
acid
molecule that donates hydrogen ions and increases the concentration of hydrogen ions in a solution
pH less than 7
adhesion
attraction between water molecules and other molecules
aliphatic hydrocarbon
hydrocarbon consisting of a linear/open chain of carbon atoms
anion
negative ion that is formed by an atom gaining one or more electrons
aromatic hydrocarbon
hydrocarbon consisting of closed rings of carbon atoms
Atom
the smallest unit of matter that retains all of the chemical properties of an element
Atomic mass
calculated mean of the mass number for an element’s isotopes
atomic number
total number of protons in an atom
balanced chemical equation
statement of a chemical reaction with the number of each type of atom equalized for both the products and reactants
Base
molecule that donates hydroxide (OH-) ions or otherwise binds excess hydrogen ions and decreases the hydrogen ions’ concentration in a solution
Buffer
substance that resists a change in pH by absorbing or releasing hydrogen (H+) or hydroxide (OH-) ions
Buffers do so by being composed of certain pairs of solutes: either a weak acid plus a salt derived from that weak acid or a weak base plus a salt of that weak base. For example, a buffer can be composed of dissolved acetic acid (HC 2H 3O 2, a weak acid) and sodium acetate (NaC 2H 3O 2, a salt derived from that acid).
Calorie
amount of heat required to change the temperature of one gram of water (H2O) by one degree Celsius
Capillary action
occurs because water molecules are
attracted to charges on the inner surfaces of narrow tubular structures such as glass tubes, drawing the water molecules to the tubes’ sides. The meniscus in the tube can be higher or lower than the meniscus of the container.
Cation
positive ion that is formed by an atom losing one or more electrons
Chemical bond
interaction between two or more of the same or different atoms that results in forming molecules
chemical reaction
process leading to rearranging atoms in molecules
chemical reactivity
the ability to combine and to
chemically bond with each other
cohesion
intermolecular forces between water molecules caused by the polar nature of water; responsible for surface tension
compound
substance composed of molecules consisting of atoms of at least two different elements
covalent bond
type of strong bond formed between two atoms of the same or different elements; forms when 2+ electrons are shared between atoms
dissociation
release of an ion from a molecule such that the original molecule now consists of an ion and the charged remains of the original, such as when water dissociates
into H+ and OH
Electrolyte
ion necessary for nerve impulse conduction, muscle contractions, and water balance
electron
negatively charged subatomic particle that resides outside the nucleus in the electron orbital; lacks functional mass and has a negative charge of -1 unit
electron configuration
arrangement of electrons in an atom’s electron shell
electron orbital
how electrons are spatially distributed
surrounding the nucleus; the area where we are most likely to find an electron
electron transfer
movement of electrons from one element
to another; important in creating ionic bonds
electronegativity
ability of some elements to attract electrons (often of hydrogen atoms), acquiring partial negative charges in molecules and creating partial positive charges on the hydrogen atoms
element
one of 118 unique substances that cannot break down into smaller substances; each element has unique properties and a specified number of protons
enantiomers
Also known as an optical isomer
molecules that share overall structure and bonding patterns, but differ in how the atoms are three dimensionally placed such that they are mirror images of each other
equilibrium
steady state of relative reactant and product concentration in reversible chemical reactions in a closed system
evaporation
change from liquid to gaseous state at a body of water’s surface, plant leaves, or an organism’s skin
functional group
group of atoms that provides or imparts a specific function to a carbon skeleton
Some of the important functional groups in biological molecules include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups. These groups play an important role in the formation of molecules like DNA, proteins, carbohydrates, and lipids.
geometric isomer
isomer with similar bonding patterns differing in the placement of atoms alongside a double covalent bond
Geometric isomers are two or more compounds with the same number and types of atoms, and bonds, but which have different geometries for the atoms.
heat of vaporization of water
high amount of energy required for liquid water to turn into water vapor
hydrocarbon
molecule that consists only of carbon and hydrogen
hydrogen bond
weak bond between slightly positively charged hydrogen atoms and slightly negatively charged atoms in other molecules
hydrophilic
describes ions or polar molecules that interact well with other polar molecules such as water
hydrophobic
describes uncharged nonpolar molecules that do not interact well with polar molecules such as water
inert gas
(also, noble gas) element with filled outer electron shell that is unreactive with other atoms. They include helium, argon, neon, xenon, krypton, radon, and Oganesson (118: last element)
ion
atom or chemical group that does not contain equal numbers of protons and electrons. Has a positive or negative charge
ionic bond
chemical bond that forms between ions with opposite charges (cations and anions)
irreversible chemical reaction
chemical reaction where reactants proceed unidirectionally to form products
isomers
molecules that differ from one another even though they share the same chemical formula
isotope
one or more forms of an element that have different numbers of neutrons
law of mass action
chemical law stating that the rate of a reaction is proportional to the concentration of the reacting substances
Litmus paper
(also, pH paper) filter paper treated with a natural water-soluble dye that changes its color as the pH of the environment changes in order to use it as a pH indicator
mass number
total number of protons and neutrons in an atom
Matter
anything that has mass and occupies space
Molecule
2 or more atoms chemically bonded
Neutron
uncharged particle that resides in an atom’s nucleus; has a mass of 1 amu
Nonpolar covalent bond
bond type of covalent bond that forms between atoms when 2+ electrons are shared equally between them
nucleus
core of an atom; contains protons and neutrons
octet rule
rule that atoms are most stable when they hold eight electrons in their outermost shells
orbital
region surrounding the nucleus; contains electrons
organic molecule
any molecule containing carbon (except carbon dioxide)
periodic table
organizational chart of elements indicating each element’s atomic number and atomic mass; provides key information about the elements’ properties
pH scale
scale ranging from zero to 14 that is inversely proportional to the hydrogen ions’ concentration in a solution
polar covalent bond
type of covalent bond that forms as a result of unequal electron sharing, resulting in creating slightly positive and negative charged molecule regions
product
molecule that is result of chemical reaction
proton
positively charged particle that resides in the atom’s nucleus; has a mass of one amu and a charge of +1
radioisotope
isotope that emits radiation comprised of subatomic particles to form more stable elements
reactant
molecule that takes part in a chemical reaction
reversible chemical reaction
chemical reaction that functions bidirectionally, where products may turn into reactants if their concentration is great enough
solvent
substance capable of dissolving another substance
specific heat capacity
the amount of heat one gram of a
substance must absorb or lose to change its temperature by one degree Celsius
sphere of hydration
when a polar water molecule surrounds charged or polar molecules thus keeping them dissolved and in solution
structural isomers
molecules that share a chemical formula but differ in the placement of their chemical bonds
substituted hydrocarbon
hydrocarbon chain or ring containing an atom of another element in place of one of the backbone carbons
surface tension
tension at the surface of a body of liquid that prevents the molecules from separating; created by the attractive cohesive forces between the liquid’s molecules
Valence shell
outermost shell of an atom
van der Waals interaction
very weak interaction between molecules due to temporary charges attracting atoms that are very close together
How many neutrons do carbon-12 and carbon-13 have, respectively?
Carbon occurs naturally in three isotopes: carbon 12, which has 6 neutrons (plus 6 protons equals 12), carbon 13, which has 7 neutrons and carbon 14, which has 8 neutrons.
how many electrons do elements in group 1 need to lose in order to achieve a stable electron configuration?
How many electrons do elements in groups 14 and 17 need to gain to achieve a stable configuration?
Elements in group 1 need to lose one electron to achieve a stable electron configuration. Elements in groups 14 need to gain 4 electrons. Elements in groups 17 1 electron.
The group 1 elements, that is, sodium, hydrogen, and lithium, all possess 1 electron in their outermost shells. This signifies that they can attain a stable configuration and an occupied outer shell by sharing or donating one electron with another molecule or atom like water.
The elements of group 14 possess 4 electrons in their outermost shell permitting them to form many covalent bonds with other atoms by gaining 4 electrons.
On the other hand, the elements of group 17 exhibit 7 electrons in their outermost shells, thus they seem to fill this shell by gaining 1 electron from other molecules or atoms, making them negatively charged ions.
cis-trans isomers
must be double bonded
enantiomers
a molecule must have at least four different atoms or groups connected to a central carbon.
If xenon has an atomic number of 54 and a mass number of 108, how many neutrons does it have?
54
Atoms that vary in the number of neutrons found in their nuclei are called
Isotope
Potassium has an atomic number of 19. What is its electron configuration?
shells 1, 2 and 3 are full and shell 4 has one electron
Which type of bond represents a weak chemical bond?
hydrogen bond
When acids are added to a solution, the pH should
decrease
We call a molecule that binds up excess hydrogen ions in
a solution a(n)
base
Each carbon molecule can bond with as many
as________ other atom(s) or molecule(s).
4
Which of the following is not a functional group that can bond with carbon?
sodium cannot bond with carbon
What property of carbon makes it essential for organic
life?
Growth and replication
Compare and contrast saturated and unsaturated triglycerides.
Saturated triglycerides contain single bonds and are solid at room temperature, while unsaturated triglycerides contain double bonds and are liquid at room temperature.
Which statement describes how buffers help prevent drastic swings in pH?
Buffers absorb excess hydrogen and hydroxide ions to prevent increases or decreases in pH. An example is the bicarbonate system in the human body.
Why are hydrogen bonds and van der Waals interactions necessary for cells?
Hydrogen bonds and van der Waals interactions form weak associations between different molecules. They provide the structure and shape necessary for proteins and DNA within cells so that they function properly. Hydrogen bonds also give water its unique properties, which are necessary for life.
What makes ionic bonds different from covalent bonds?
ionic bonds are created between ions. The electrons are not shared between the atoms, but rather are associated more with one ion than the other. Ionic bonds are strong bonds, but weaker than covalent bonds, meaning it takes less energy to break a ionic bond compared with a covalent bond
How many orbitals does each shell have?
How many electrons can each shell hold?
