Ch 2 BIO 1200
compared with liquid water, ice has :
-a more orderly arrangement of water molecules -greater hydrogen bonds between individual water molecules
molecules that are predicted to easily dissolve in water
-carbohydrates that contain -OH groups -ions that carry full electric charges
Describe molecules that ONLY have hydrophobic regions.
-contain many nonpolar covalent bonds -relatively insoluble in water -dissolve well in nonpolar solvents
Arrange these solutions in order of increasing proton concentration (lowest at top) -neutral, alkaline, acidic
1. alkaline 2. neutral 3. acidic
Rank each state of water in order of increasing density, starting with the least dense state at the top of the list.
1. water vapor 2. ice 3. liquid water
If a solution has a pH of 8, what is the concentration of protons in the solution?
10^-8 M
Carbon has six protons, six electrons, and six neutrons. What is it's atomic mass?
12 (protons + neutrons)
A mole of an element contains:
6.022 x 10^23 atoms
Why is the atomic mass of carbon reported in the periodic table slightly greater than its predicted mass?
Because of the presence of a small amount of heavier isotopes
True or false: Matter exists in only one of two states: solid or liquid
False
A base will absorb _______ ions in solution
Hydrogen
If a person travels from the Earth to the Moon, which has less gravitational pull, how will their mass and weight be affected?
Mass will be the same but their weight will be different
What type of bonds are most likely to be found in a hydrophobic molecule?
Nonpolar covalent
In a micelle, which portion of the amphipathic molecules are oriented to the surface of the sphere?
The polar region
when do atoms tend to be more stable?
When their outer shells are filled with electrons
In pure water what are the concentrations of H+ and OH-?
[H+] = 10^-7 M [OH-] = 10^-7 M
solvent
a liquid that can dissolve other substances
aqueous solution
a solution in which water is the solvent
base
absorbs hydrogen ions in solution
If you add H+ ions to a solution, it becomes more:
acidic
a solution with a pH below 7
acidic
Cohesion
aids the movement of fluids through plant vessels
A solution with a pH above 7
alkaline
high heat of vaporization
allows animals to cool themselves through evaporation
surface tension
allows some insects to walk on the surface of the water without sinking
Adhesion
allows water to coat the surface of the digestive track
molecules containing a hydrophilic region and a hydrophobic region
amphipathic
an ion with a net negative charge
anion
a solution made with water
aqueous solution
The fundamental unit of matter is the
atom
A mole of any substance contains the same number of particles as there are:
atoms in exactly 12g of carbon; in Avogadro's number
living organisms minimize changes in their internal pH using compounds called:
buffers
Which medical applications rely on the injection of radioisotopes into the body?
cancer therapy, PET scans
Which four elements make up approximately 95% of living matter?
carbon hydrogen nitrogen oxygen
an ion that has a net positive charge
cation
the rate of formation of products equals the rate of formation of reactant
chemical equilibrium
a molecule composed for two or more different elements
compound
the amount of a solute dissolved in a unit volume of solution
concentration
a chemical bond in which two atoms share a pair of valence electrons
covalent bonds
One _____ equals 1/12 the mass of a carbon atom
dalton
hydrophilic molecules
dissolve in water; water loving
In the periodic table, the elements in the same row have the same number of:
electron shells
A measure of the ability of an atom in a chemical compound to attract electrons to its outer shell from another atom
electronegativity
Which type of subatomic particle is found outside the nucleus?
electrons
Each specific type of atom is called an
element
The capacity to do work is known as:
energy
True or false: An element is made up of two or more atoms
false
An element with a larger mass contains _____ an element with a smaller mass
fewer atoms per gram than
High specific heat, surface tension, and cohesion are several properties of water involving what type of bonds?
hydrogen
hydrochloric acid is considered an acid because it releases _____ ions into the solution
hydrogen
forms when a hydrogen atom from one polar molecule becomes electrically attracted to an electronegative atom in another polar molecule
hydrogen bond
a chemical reaction that utilizes water to break apart molecules
hydrolysis reaction
water loving
hydrophilic
Amiphipathic molecules have both ______ and ______ regions.
hydrophilic and hydrophobic
water fearing
hydrophobic
at atom or molecule that gains or loses one or more electrons and acquires a net electric charge
ion
Molecules are likely to dissolve easily in water if they contain what type of bonds?
ionic or polar covalent bonds
an element that exists in multiple forms that differ in the number of neutrons they contain
isotopes
Elements have increasingly full orbitals as you look from:
left to right on the periodic table
Which component of humans has the greatest percent of water?
lungs: 90%
An element's atomic _____ is based on the protons and neutrons it contains
mass
Matter is anything that has ____ and takes up ____.
mass; space
the sphere formed by long amphipathic when they are mixed with water
micelle
number of moles of a solute dissolved in 1 L of water
molarity
The sum of the atomic masses of all the atoms in a molecule.
molecular mass
how can substance dissolve in water?
must be electrically attracted to water molecules
pH is defined as the _____ _____ to the base 10 of the _____ ion concentration
negative; logarithm; hyrogen
Electron
negatively charged; located outside the nucleus
Isotopes of the same element differ in their number of:
neutrons
a covalent bond in which the electrons are shared equally by the two atoms
nonpolar covalent bond
hydrophobic molecules tend to contain many
nonpolar covalent bonds
Due to the presence of protons, an atom's _____ has a net positive electric charge
nucleus
An element's atomic _____ is based only on the number of protons
number
Valence electrons are found in:
outermost energy shells
The polar groups of a micelle are oriented toward the _____, while its nonpolar groups are oriented toward the _____.
outside; inside
Which solution contains the highest concentration of protons? -pH 7 -pH 5 -pH 8 -pH 10 -pH 2
pH 2
unequal sharing of electrons
polar covalent bond
Pure water can ionize into
positively charged protons (H+) and negatively charged hydroxide (OH-) ions
Proton
positively charged; located in the nucleus
the end result of a chemical reaction
product
colligative properties
properties of a solution that depend strictly on the total number of dissolved solutes and not the specific type of solute
Atoms of different chemical elements can be differentiated based on the number of which subatomic particle?
proton
An atom's atomic number is based on the number of _____ it contains
protons
Which two particles are the primary determinants of an element's atomic mass?
protons, neutrons
Which of the following are considered subatomic particles?
protons, neutrons, and electrons
an isotope found in nature that is inheritely unstable and usually does not exist for long periods of time; decay and emit energy in the form of radiation
radioisotopes
a substance that participates in a chemical reaction and becomes changed by that reaction
reactant
acid
releases hydrogen ions into solution
Substances dissolved in a liquid
solute
A solution is composed of _______ dissolved in a ________.
solutes; solvent
a liquid that contains one or more dissolved solutes
solution
the liquid in which a solute is dissolved
solvent
Substance A has a higher specific heat than substance B. With all other factors equal, which requires the most energy to heat equal masses of A and B to the same temperature?
substance A
solute
substances dissolved in a liquid
A solution at pH 6 is more acidic than a pH 7 because?
the concentration of H+ (protons) is 10x higher
heat of vaporization
the heat energy required to convert 1 mole of a substance from liquid to gas
specific heat
the heat energy required to raise the temperature of 1 gram of a substance by 1 degree celsius
heat capacity
the heat energy required to raise the temperature of an entire object
heat of fusion
the heat energy that must be withdrawn or released from a substance to convert it from liquid to solid
Why are atoms electrically neutral?
there are equal numbers of protons and electrons
Elements are electrically neutral because:
there are equal numbers of protons and electrons in a given atom
Carbon shares the most similar bonding properties with silicon because:
they share the same number of valence electrons
Why do micelles form?
to minimize interactions of nonpolar regions of molecules with water
A molecule is composed of
two or more atoms bonded together
Neutron
uncharged; located in the nucleus
Unpaired _____ electrons enable chemicals bonds to form among atoms
valence
evaporation
vaporization of water; helps animals dissipate body heat
hydrolysis reaction
water is used to break apart another molecule
When does an ionic bond occur?
when a cation binds to an anion