Biology Chapter 2
An oxygen molecule (O2) contains a double bond, in which a total of____ electrons are shared.
4
Oxygen has 8 electrons. How many valence electrons does it have
6
Nitrogen contains 7 protons, 7 neutrons, and 7 electrons. What is the atomic number
7
Which of the following contributes to water's stability in a liquid state
A high heat of vaporization
Which of the following best describes how a hydrogen bond forms
A partially positive hydrogen atom and a partially negative atom in two polar molecules are attracted by electrostatic interactions
Contains more H+ then OH- ions
Acidic
Building block for all living matter
Carbon
When the forward rate of a chemical reaction is equal to its reverse rate, the reaction has reached a state called
Chemical equlibrium
Negatively charged, located outside the nucleus
Electron
Each specific type of atom is called
Element
True or False: An element is made up of two or more types of atoms
False
True or False: Molecules that contain covalent bonds are rigid, inflexible structures
False
True or False: Van der Waals forces are stronger than hydrogen bonds
False
An oxygen molecule(O2) contains a double bond, in which total of four electrons are shared:
Four
Which of the following covalent bonds are nonpolar
H-H, O-O, C-H
Which of following are compounds
HF, NaCl, C6H12O6
The heat energy required to raise the temperature of an entire object
Heat capacity
Within an atom's structure, electrons can be found:
In cloudlike orbitals
The addition of solutes to water will:
Increase its boiling point, decrease it freezing point
Bond between a cation an anion
Ionic bond
What type of bond occurs when a cation binds to an anion
Ionic bond
Contains equal numbers of OH- and H+ ions
Neutral
What type of bonds are most likely to be found in a hydrophobic molecule.
Nonpolar covalent
Bond in which two atoms share electrons equally
Nonpolar covalent bond
Which of the following covalent bonds are polar
O-H, N-H
When water ionizes, it produces what ions?
OH-
Component of bones and shells
Phosphorous
Bond in which two atoms share electrons unequally
Polar covalent bond
Molecules are likely to dissolve easily in water if they contain what type of bonds?
Polar covalent bonds, ionic bonds
Positively charge, located in the nucleus
Protons
Which two particles are the primary determinants of an element's atomic mass
Protons, Neutrons
The heat energy required to raised the temperature of 1 gram of a substance by 1 degree Celsius
Specific heat
What part of an amphipathic molecule would be oriented toward the center of a micelle
The nonpolar region
What is the molarity of a solution
The number of moles of solute in 1L
Which of the following statements is true of a polar covalent bond
The shared electrons are closer to one nucleus than to the other
Atoms are chemically the most stable when which of the following occurs
Their outer shell is full
Which of the following statements describe hydrophillic molcules
They are soluble in water
When water freezes
Water molecules are packed into a more orderly formation; the rate of hydrogen bond breakage slows
In pure water, what are the concentrations of H+ and OH- ions each
[H+]=10^-7 M [OH-]=10^-7 M
Compared with liquid water, ice has
a more orderly arrangement of water molecules. more hydrogen bonds between individual water molecules
A Na+ ion forms when
a sodium atom loses an electron
A Na+ ion forms when:
a sodium atom loses an electron
A substance that releases hydrogen ions into solution is called
acid
If you add H+ ion to a solution, it becomes more
acidic
The property of water that refers to its ability to be attracted to and adhere to a surface that is not electrically neutral is
adhesion
Most chemical reactions in living organism involve reactants and products that are dissolved in__________ solutions
aqueous
Molecules with covalent bonds
are flexible
A substance that absorbs hydrogen ions in solution is called a
base
Hydrolysis reactions
break apart molecules via water
What type of compound minimizes pH fluctuations in the fluids of living organisms
buffer
Which of the following mechanisms help organisms to regulate their internal pH
buffers
A_______ is a substance that speeds up the rate of a chemical reaction
catalyst
Chemical reactions require a source of energy and also may require a substance called
catalyst
An atom with a net positive charge is an
cation
An ionic bond forms when a positively charged ion called ______, Interacts with a negatively charged ion, called_______
cation, anion
The movement of water through the vessels in a plant is aided by the property of water called
cohesion
The phenomenon of water molecules attracting each other is called
cohesion
The amount of solute (in grams) dissolved in a given volume of solution is the solution's
concentration
One________equals one 12th the mass of a carbon atom
dalton
If you add H+ to a solution, the pH:
decreases
What is a likely predictor of how many covalent bonds an atom can form
electron configuration in the outermost shell
The region of space surrounding an atomic nucleus in which there is a high probability of finding______ is called an orbital
electrons
The capacity to do work is known as
energy
Chemical________ is reached when the rate of the forward reaction is equal to the rate of the reverse reaction
equilibrium
High specific heat, surface tension, and cohesion are several properties of water involving________ bonds
hydrogen
Hydrochloric acid is considered an acid because it releases______ions into solution
hydrogen
An atom that has a net electric charge due to the gain or loss of electrons is called
ion
An atom with a net electric charge is called an
ion
A covalent bond is one in which a pair of electrons:
is shared between two atomss
Anything that contains mass and occupies space called
matter
The sum of the atomic masses of all atoms in a molecule is equal to the molecule's________ mass
molecular
What term describes two or more atoms that are bonded together
molecule
Water has a high heat of fusion. This means that
much energy must be withdrawn to cause water to change from a liquid state to solid
pH is defined as the __________________________ to the base 10 of the _____________ ion concentration
negative logarithm, hydrogen
An elements atomic mass includes the number of protons and the number of
neutrons
Isotopes of the same element differ in their number of
neutrons
The region of space in which there is a high probability of finding an electron is called an
orbital
Which of the following contains a maximum of two electrons
orbital
The polar groups of a micelle are oriented toward the________, while its nonpolar groups are oriented toward the ________.
outside;inside
When NaCl dissolves in water, aqueous Na+ becomes surrounded by the partially negatively charged ________ atoms of water molecules, and Cl becomes surrounded by the partially positively charged______ atoms of water
oxygen; hydrogen
In a water molecule(H20), each hydrogen atom has a partial _________ charge, and the oxygen atom has a partial___________ charge
positive;negative
Pure water can ionize into
positively charge protons(H+) and negatively charged hydroxide (OH) ions
Pure water can Ionize into
positively charge protons(H+) and negatively charged hydroxide (OH-) ions
In the conversion of methane and oxygen to carbon dioxide and water, carbon dioxide is an
product
An elements atomic number is based on the number of
protons
What type of subatomic particle occurs in each different element in a unique number and is therefore used to identify specific elements
protons
Atoms are electrically neutral because they have equal numbers of
protons and electrons
Within an atom
protons and neutrons have nearly equal masses, while electrons have a much smaller mass
An atom's atomic number is based on the number of
protons it contains
An electron________ is composed of one or more orbitals
shells
Oxygen has eight electrons. How many valence electrons does it have?
six
Substances dissolved in liquid are known as
solutes
Electron in an atom's outermost energy shells are called
valence electrons
An atom's ability to form a covalent bond with another atom depends on how many:
valence electrons it has
An aqueous solution is one in which the solvent is
water
An orbital can contain a maximum of
2 electrons
Contains more OH- than H+ ions
Alkaline
___________dissolved in a _________ form a solution
Solutes, solvent
A liquid that can dissolve substances is known as a
Solvent
The molecular mass of glucose is 180 g. If 90g of glucose are dissolved in enough water to make 1L, what is the molarity of the solution
0.5 M
Order the following elements based one number of atoms in a gram of each. Place the element with the most atoms per gram at the top and the element with fewest atoms per gram a the bottom of the list. The approximate atomic mass of each element is listed next to it.
1. Hellium(4) 2. Carbon(12) 3. Oxygen(16) 4.Sodium(23)
If a solution has pH of 8, what is the concentration of protons in the solution
10^-8 M
A mole of any substance contains the same number of particles as:
12g of carbon
Oxygen has 8 protons, 8 electrons, and 8 neutrons. What is its atomic mass
16
The atomic mass of carbon is 12, and the atomic mass of hydrogen is 1. What is he molecular mass of a methane molecule(CH4)
16
The atomic mas of hydrogen is 1, and the atomic mass of oxygen is 16. What is the molecular mass of a water molecule(H2O)
18
Nitrogen has three unpaired electrons in its outer shell What is the maximum number of covalent bonds that a nitrogen atom can form with other atoms while still remaining uncharged?
3
How many electrons are shared in a double bond
4
Oxygen contains 8 protons, 8 electrons, and 8 neutrons. What is the atomic number
8
Which of the following best describes how a hydrogen bond forms?
A partially positive hydrogen atom and a partially negative atom in two polar molecules are attracted by electrostatic interactions.
What is a chemical element?
A pure substance composed of only one type of atom
Which of the following solutions contains the highest concentration of protons
A solution with pH 2.0
Why are atoms likely to share electrons
Because they have unfilled outer electron shells
Write the chemical formula for a compound containing one carbon atom and four hydrogen atoms
CH4
Sodium (Na) has 1 electron in its outer shell, and has the tendency to release it to satisfy the octet rule. Chlorine(Cl) has 7 electrons in the outer shell and desires to capture an electron to complete the octet rue. Which atom is more electronegative?
Chlorine
Which type of subatomic particle is found outside the atomic nucleus
Electron
The_______ of an atom is a measure of its ability to attract electrons when in a bond with another atom
Electronegativity
What determines whether a covalent bond is polar or nonpolar
Electronegativity of the atoms involved in the bond
Which of the following best describes a contemporary model of electron movement within atoms
Electrons move in orbitals, although their exact location cannot be precisely predicted in these orbitals
____________, which vaporization of water, helps animals to dissipate body heat
Evaporation
The heat energy that must be withdrawn or released from a substance to convert it from liquid to solid
Heat of fusion
The heat energy required to convert 1 mole of a substance from liquid to gas
Heat of vaporization
Polar covalent O-H bonds in water molecules enable hydrogen bonds to form between water molecules. Which of the properties of water result from hydrogen bond formation?
High heat of vaporization, Surface tension, Adhesion, Cohesion, High specific heat.
Occurs in water
Hydrogen
Small molecules may bind to enzymes via what type of bond
Hydrogen
The bond between the hydrogen atom and oxygen atom of separate water molecules is an_________ bond
Hydrogen
Bond between atoms with partial positive and partial negative charges
Hydrogen bonds
Which types of chemical bonds are easily broken in water
Hydrogen bonds and Ionic bonds
Which of the following is a trace element that plays an important role in the transport of oxygen in the blood of many animals
Iron
Uncharged, located in the nucleus
Neutron
The outermost shell of hydrogen has 1 electron. How many covalent bonds can a hydrogen atom typically form?
One
In a water molecule(H2O), the_________ atom has a partial negative charge, and the ________ atom has a partial positive charge
Oxygen, Hydrogen
What shapes do electron orbitals assume
Propeller-type, Spherical
Which of the following are considered subatomic particles
Protons, neutrons, and electrons
What is all true about atoms that have partially filled energy shells
Tend to share,lose, or gain electrons. Can form compounds
Elements in the same chemical group have the same bonding properties for which reason
They have the same number of valence electrons
Which of the following properties are shared by many chemical reactions that occur in calls
They often require a catalyst, They require energy, They tend to proceed toward equilibrium
Which of the following properties are shared by many chemical reactions that occur in cells
They require energy. They often require a catalyst. They tend to proceed toward equilibrium
Why micelles form
To minimize interactions of nonpolar regions of molecules with water
The surface tension of water
allows it to form droplets
The hydrogen bonds between water molecules form between
an oxygen atom on one water molecule and a hydrogen atom on a second water molecule
Van der Waals interactions can form between
any atoms
The fundamental unit of matter is the
atom
The smallest functional unit of matter is the
atom
A mole of any substance contains the same number of particles as there are:
atoms in exactly 12g carbon
To dissolve in water, a substance must:
be electrically attracted to water
Amphipathic molecules organize themselves to form
bilayers with their nonpolr regions facing inward towards each other and the hydrophillic regions facing outward
Properties of a solution that depend strictly on the total number of dissolved solutes, and not the specific type of solute, are called
colligative properties
Molecules that catalyze important chemical reactions in cells are called
enyzmes
Molecules that catalyze important chemical reactions in cells are called
enzymes
In a chemical reaction, If there is no longer a change in the concentration of reactants and products, then
equilibrium has been reached
You are cooled when you sweat because the water in the sweat______which requires a lot of ______ in the form of body heat
evaporates,energy
When sweat evaporates from your skin you are cooled because
evaporation of sweat requires energy in the form of body heat
In a polar covalent bond, the shared electrons are closer to the nucleus of the atom with
greater electronegativity
An amphipathic molecule
has nonpolar and polar regions
Compared to a small puddle of water, a lake has
higher heat capacity, but the same specific heat
Sodium hydroxide is a base because when dissolved in water it binds_______ ions that are in solution
hydrogen
An elements atomic_______ is based on the protons and neutrons it contains
mass
In ice, H20 molecules move________ slowly than in water, and consequently hydrogen bonds are broken_______ frequently
more;less
Hydrophobic molecules tend to contain many________ covalent bonds such as the bond between two carbon atoms or the bond between carbon and hydrogen
nonpolar
When micelles form, the interactions between water and the_____ regions of amphipathic molecules are minimized
nonpolar
Due to the presence of protons, an atom's________ has a net positive electrical charge
nucleus
An elements atomic_________ is based only on the number of protons
number
A catalyst will cause a chemical reaction to
occur more quickly
The outermost shell of hydrogen has 1 electron. How many covalent bonds can a hydrogen atom typically form
one
When outer electrons shells contain between_________ and ________ electrons, the opportunity for covalent bond formation is available
one; seven
An______ bond is formed when two atoms of different electronegativities share electrons
polar covalent
Molecules are likely to dissolve easily in water if they contain what type of bonds
polar covalent bonds and ionic bonds
The nucleus of an atom has a net____________ charge
positive
Unstable isotopes that emit subatomic particles and/or radiation are called
radioisotopes
Van der Waals forces arise when
random electron movement creates short-lived attractions
In the conversation of methane and oxygen to carbon dioxide and water, oxygen is
reactant
Which of the following describes hydrophobic molecules
relatively insoluble in water. contain many nonpolar covalent bonds
To freeze water, energy is
released
The kidneys can help organisms cope with changes in pH by:
secreting alkaline compounds into the bloodstream; secreting acidic compounds into the bloodstream
What substance is acidic
stomach fluid
A solution at pH 6 is more acidic than a solution at pH 7 because the concentration of H+ (protons) is ______ times higher than that in a solution at pH7
ten
Which of the following is true about atoms that have partially filled energy shells
tend to share,lose,or gain electrons. can form compounds
All living organisms require_______ elements. These elements are present in extremely small quantities but are still essential for normal growth and function
trace
Water, with the chemical formula H20, contains_____ hydrogen atoms and______ oxygen atoms
two;one
Even though it requires energy to change a liquid to a gas, some water molecules break their hydrogen bonds at ordinary temperatures by:
vibrating at higher energy
