ch 2
Atomic number
the number of protons in the nucleus of an atom
polar covalent bonds
unequal sharing of the bonding pair that results in a partial negative charge on the chlorine atom and a partial positive charge on the hydrogen atom, water-soluble
Electrons in an atom's outermost energy shells are called ______ electrons.
valance
water functions
1. chemical reactions (hydrolosis/condensation) 2. provides force or support 3. removes toxic waste components 4. evaporative cooling 5. cohesion and adhesion 6. surface tension 7. lubrication
What does pH of a solution effect?
1. the shapes and functions of molecules 2. the rates of many chemical reactions 3. the ability of two mollecuels to bind tog 4. the ability of ions or mollecules to dissolve in water
____________ of hydrogen = 1 mole.
1g
Nitrogen has five electrons in its outer shell, so it can bond with up to ______ other atoms to complete its outer shell.
3, because two of the electrons are paired.
Adding NH3 (ammonia) to water makes NH4+. What will be the general pH of this new solution, and what will happen to the ion concentrations?
Alkaline; decreased H+ ions and increased OH- .
Atom vs molecules vs ion vs vs electrons vs element vs compound
Atoms-single neutral particles. Molecules-neutral particles made of two or more atoms bonded together. ion-a positively or negatively charged particle. electrons-negatively charged microparticles elements-a pure substance made up of one type of atom compound -a substance made from 2 or more electrons chemically bonded in a fixed ratio
Why are atoms likely to share electrons?
Because they have unfilled outer valence shells.
Why are atoms likely to share electrons? Multiple choice question. Because they contain seven or fewer total electrons. Because they have a high electronegativity. Because they have unfilled outer valence shells. Because they are considered an isotope. Because they are considered a noble gas.
Because they have unfilled outer valence shells.
They have two electron shells
Carbon & Nitrogen
Valence electrons
Electrons on the outermost energy level of an atom that are free to participate in chemical bond formation
T/F: A hydrogen atom of one water molecule binds via a hydrogen bond to a hydrogen atom of another water molecule.
F
T/F: Bonds between water molecules are stronger than the bonds between the atoms within a water molecule.
F
T/F: Ice is denser than liquid water at all temperatures
F
Which is the most dense?
Liquid
What four elements are the most common in living organisms?
Nitrogen Carbon Hydrogen Oxygen
They have the same number of electrons in their outermost shells
Nitrogen & Phosphorus
What type of subatomic particle occurs in each different element in a unique number and is therefore used to identify specific elements?
Proton
__________blank make(s) up the nucleus of an atom. Protons and electrons Protons and neutrons DNA and RNA Neutrons and electrons DNA only
Protons and neutrons
They have three electron shells.
Sodium & Chlorine
What is the heat of fusion of a substance? Multiple choice question. The amount of heat energy required to raise the substance's temperature by 1 degree Celsius The amount of heat energy required to convert 1 mole of the substance from liquid to gas The amount of heat energy released when 1 mole of the substance is converted from liquid to solid
The amount of heat energy released when 1 mole of the substance is converted from liquid to solid
Condensation
The change of state from a gas to a liquid
Heat of vaporization
The heat energy required to convert 1 mole of a substance from liquid to gas
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
What happens when water freezes? Multiple select question. The rate of hydrogen bond breakage slows. Water molecules are packed into a less dense formation. The H2O molecules in ice are in a much more orderly arrangement than in the liquid state. Water loses its hydrophilic status and becomes more hydrophobic.
The rate of hydrogen bond breakage slows. Water molecules are packed into a less dense formation. The H2O molecules in ice are in a much more orderly arrangement than in the liquid state.
Why would the polar part of the amphipathic molecule would not be oriented toward the center of a micelle?
This region is hydrophilic. Thus, it will be at the surface of the micelle, where it is attracted to the surrounding water molecules.
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.
an atom with one unpaired electron in its outer shell. can cause considerable cellular damage.
electronegativity
an atom's attraction for the electrons in a covalent bond
cohesion
an attraction between molecules of the same substance
The ____________ of an atom is a relative measure of its mass compared to other atoms.
atomic mass
adhesion
attraction between molecules of different substances
how does water resist changes to temperature?
because of its specific high heat related to hydrogen bonding
What type of compound minimizes pH fluctuations in the fluids of living organisms? Multiple choice question. base buffer water acid
buffer
Atoms share a pair of electrons when they form a(n) ____ bond.
covanlent
The measure of an atom's ability to attract electrons when in a bond with another atom is called its
electronegativity
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.
electronegativity.
In a chemical reaction, if there is no longer a change in the concentration of reactants and products, then ______. Multiple choice question. catalysis has ended equilibrium has been reached all energy in the system has been expended all reactants have become products
equilibrium has been reached
High specific heat, surface tension, and cohesion are several properties of water involving
hydrogen bonds
When water is heated, the rate at which _____ bonds break increases, and water molecules are converted to the______ state.
hydrogen, gaseous
Reactions in which water is used to break apart other molecules are known as __________blank reactions. hydrophilic hydrophobic dehydration anabolic hydrolysis
hydrolysis
Solutes that easily dissolve in water are said to be hydrophobic. hydrophilic. polar molecules. all of the above. b and c only.
hydrophilic. polar molecules.
An atom with a net electric charge,that has gained or lost electrons, is called a(n) ______.
ion
Which two elements show similarities in the pattern of chemical bonding?
lithium and Sodium
A ____________ of a substance contains the same number of particles as there is in 12g of carbon.
mole
Colligative properties depend on the ______ dissolved in a solution. Multiple choice question. type of particles number of particles electrical charge on particles size of particles
number of particles
ionic bonds are formed when
one or more electrons are transferred from one atom to another
A free radical is a molecule containing an atom with a single unpaired electron in its ______.
outer shell
The unequal sharing of electrons between the oxygen and hydrogen atoms within a water molecule makes water a ____________ molecule.
polar
atomic weight
protons + neutrons
covalent bonds
sharing of electrons that holds atoms together
A solution is composed of ______ dissolved in a ______.
solutes; solvent
atoms combine to form a molecule with 3 dimensional shape, determined by _______.
the arangement/angles and number of bonds between atoms
hydrolosis
the chemical breakdown of a compound due to reaction with water.
chemical behavior of an atom is determined by
the distribution of electrons in electron shells
The molecular mass of glucose is about 180 g/mol. If 45 g of glucose is dissolved in water to make a final volume of 0.5 L, what is the molarity of the solution? 0.125 M 0.25 M 0.5 M 1.0 M 2.0 M
0.5 M how?
Hydrogen has a total of ____________ electron(s), ____________ are in the valence shell, and ____________ lie in the p orbitals.
1,1,0
carbon 1. how many electrons? 2. how many bonds can it make? 3.polar/non polar?
1. 4 2. up to 4 3. can be polar/non polar
T/F The higher the pH value, the lower the concentration of protons.
T
What does the atomic number of an atom represent?
The number of neutrons
surface tension
the uneven forces acting on the particles on the surface of a liquid that creates tension
Why do proteins need to change shape?
to accomidate a neg charge
The most common type of carbon atom has six protons, six electrons, and six neutrons. What is its atomic mass?
12 amu 12 Daltons
____________ of lithium = 1 mole.
7g
T/F: The bonds between water molecules are stable.
F
T/F: covalent bonds are rigid
F. rotation around single covalnet bonds allows molecules to change shape
True or false: Molecules that contain covalent bonds are rigid, inflexible structures.
F: Molecules containing covalent bonds are flexible and can change their shape when the atoms rotate around covalent bonds.
T/F: A Na+ ion forms when a sodium atom gains an electron.
F: loses an electron
Which ions are produced when water ionizes?
H+ OH-
They have one electron shell.
Hydrogen & Helium
T/F: covalent bonds are not easily broken under normal biological conditions of temperature and pressure
T
T/F: covalent bonds have definate and predictible shape
T
specific heat
The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius
Van der Waals interactions
Weak attractions between molecules or parts of molecules that result from transient local partial charges.
non polar covalent bond
a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge, not water soluble
One ______ equals 1/12 the mass of a carbon atom.
dalton
The sum of the atomic masses of all the atoms of a molecule is its atomic weight. molarity. molecular mass. concentration. polarity.
molecular mass.
An _______ containing an atom with a single, unpaired electron in its outer shell is known as a free radical.
molecule
The ______ of a solution is the negative base 10 logarithm of the H+ concentration of the solution.
pH
evaporative cooling / heat of vaporization
property of a liquid where the surface becomes cooler during evaporation due to the loss of molecules
Consider the reaction: CH4 + 2 O2 ⇌ CO2 + 2 H2O. Oxygen serves as a(n) ______. Multiple choice question. catalyst product enzyme reactant
reactant
______ is the amount of energy required to raise the temperature of 1 gram of a substance by 1o1o C.
specific heat
The more electronegative an atom, the more ______.
strongly it pulls shared electrons toward itself
The molecular mass of a molecule is equal to the ______ in the molecule. Multiple choice question. total number of atoms sum of the atomic masses of all atoms average of the atomic masses of all atoms
sum of the atomic masses of all atoms
Mark the following statements as true or false concerning water's relevance to living systems. 1. Ten to twenty percent of the body weight in humans is from water. 2. Water is the universal solvent, transporting dissolved substance in bodily fluids. 3. Water bathes organs in fluid, which provides protection and support. 4. The high specific heat of water means that we only lose a small amount of heat when the sweat on our skin evaporates. 5. Water plays a major role in our bodies' chemical reactions. 6. Water plays a much more important role in plants than in animals, due to the role of water in photosynthesis.
1. False 2. True 3. True 4.False 5. True 6. False
Decide which example best describes each property of water. 1. Water is less dense at 0°C compared to 4°C. 2. Water provides structural support due to its inability to be compressed. 3. The charged ends of a water molecule allow it to surround a solute in solution. 4. The temperature of water rises slowly due to its high specific heat; requiring a lot of energy to convert liquid water to water vapor. 5. While hydrogen bonds are constantly breaking and reforming, a large percentage of the hydrogen bonds between water molecules exist at all times. 6. Due to hydrogen bonding, water tends to adhere to surfaces, such as the lining of the digestive tract. 7. The addition of water can break apart molecules into two smaller molecules. 8. Water is formed when two molecules come together to form a large molecule.
1. Ice floats 2. Turgid pressure in plants 3. Solvent 4. Evaporative cooling 5. Cohesive force 6. Lubricant 7. Hydrolysis 8. Dehydration reaction
Regulation of breathing is controlled not by the amount of oxygen circulating in the blood but by blood pH. When the blood becomes too acidic, receptors in the brain respond to changes in blood pH and increase breathing rate. Order the following events to show how the body maintains stable blood pH when blood carbon dioxide levels change. Assume a person is exercising and her muscles are releasing carbon dioxide.
1. Increase in carbon dioxide in the blood. 2. Carbon dioxide combines with water to form carbonic acid. 3. Carbonic acid dissociates forming bicarbonate and hydrogen ions. 4. pH decreases in the blood (It becomes more acidic). 5. Receptors in the brain detect an increase in acidity of blood. 6. Increase in breathing rate, exhaling more carbon dioxide. 7. Carbonic acid dissociates into water and carbon dioxide. 8. pH of the blood increases (become more basic).
hydrogen bond roles
1. holds two strands of dna tog 2. holds peptides tog 3. assists enzymes in subtrate bonding 4. helps antibodies bind to their subtrate
Hydrogen bonds differ from covalent bonds in that 1. covalent bonds can form between any type of atom, and hydrogen bonds form only between H and O. 2. covalent bonds involve sharing of electrons, and hydrogen bonds involve the complete transfer of electrons. 3. covalent bonds result from equal sharing of electrons, but hydrogen bonds involve unequal sharing of electrons. 4. 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. 5. covalent bonds are weak bonds that break easily, but hydrogen bonds are strong links between atoms that are not easily broken.
4. 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.
Which of the following changes in the physical state of water require the input of energy? Multiple select question. Changing from liquid to gas Changing from gas to solid Changing from gas to liquid Changing from solid to liquid Changing from liquid to solid
Changing from liquid to gas Changing from solid to liquid
6 CO2 + 6 H2O + Light → C6H12O6 + O2 is an example of a chemical reaction. What is occurring during this reaction? Atoms are split and reform as new molecules. Protons and neutrons are reorganized to form new structures. Substances are changed into other substances by the making or breaking of chemical bonds.Correct Shells of atoms divide in order to transport protons to other atoms.
Substances are changed into other substances by the making or breaking of chemical bonds
T/F: The fluid nature of water is due to hydrogen bonds continually breaking and reforming.
T
T/F: mollecules may change their shape
T
valence electrons
The electrons in the outermost shell (main energy level) of an atom; these are the electrons involved in forming bonds.
When is heat abosrbed and released?
abosrbed: when hydrogen bonds break released: when hydrogen bonds form
How do proteins change shape?
adding and removing phosphate
isotopes
all have the same number of protons but different numbers of neutrons
Chemical reactions in living organisms require energy to begin. usually require a catalyst to speed them up. are usually reversible. occur in liquid environments, such as water. are all of the above.
all of the above.
electrons that orbit the nucleus of an atom (check all that apply) a) require input of continuous amounts of energy to move between shells b) require input of discrete amounts of energy to move between shells c) randomly move between different shells d) have lower potential energy as they move farther from the nucleus e) have lower potential energy as they move closer to the nucleus
b, e
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
carbon, hydrogen, nitrogen, and oxygen
Stable blood serum has a pH of around 7.4. The release of bicarbonates as a buffer to maintain this pH in a body with high hydrogen levels would cause the pH to move Multiple Choice from neutral to slightly acidic. from acidic to neutral. from acidic to slightly alkaline. from alkaline to neutral.
from acidic to slightly alkaline.
The property of water that allows the basilisk lizard to run across its surface is Multiple Choicethe high surface tension caused by the nonpolar qualities of water .the high surface tension caused by the polar qualities of water .a high amount of OH− ions, making the water more viscous. a high amount of H+ ions, making the water more viscous.
the high surface tension caused by the polar qualities of water.
Their outermost electron shell is full.
Helium & Argon
Polar covalent O-H bonds in water molecules enable hydrogen bonds to form between water molecules. Which of the following properties of water result from hydrogen bond formation? Multiple select question. High specific heat Adhesion Surface tension Neutral pH Cohesion High heat of vaporization
High specific heat Adhesion Surface tension Cohesion High heat of vaporization
T/F: As temperature drops the bonds between water molecules are less likely to break.
T
T/F: In a polar covalent bond, the shared electrons are closer to the nucleus of the atom with greater electronegativity.
T
T/F: The polar covalent bonds between hydrogen and oxygen atoms within a water molecule create slight positively and negatively charged ends to the molecule.
T
Which of the following statements are true of a polar covalent bond? Multiple select question. The atoms in the bond differ in electronegativity. The atoms in the bond have the same electronegativity. The electrons are transferred completely from one atom to the other. The shared electrons are equidistant between the nuclei of the two atoms. The electrons are closer to the nucleus of the atom with lower electronegativity. The two atoms in the bond share the electrons unequally.
The atoms in the bond differ in electronegativity. The two atoms in the bond share the electrons unequally.
What is a likely predictor of how many covalent bonds an atom can form? Multiple choice question. The electron configuration in the outermost shell The total number of electron shells The row of the periodic table that contains the atom The number of electrons in the innermost shell
The electron configuration in the outermost shell
What part of an amphipathic molecule would be oriented toward the center of a micelle? Multiple choice question. The polar region The charged region The nonpolar region
The nonpolar region
In which of the following scenarios are atoms the most stable? Their outer shells are filled with electrons. They have 8 electrons in the orbitals closest to the nucleus. The number of electrons equals the number of neutrons. The number of electrons equals the number of protons. The atoms are on the left side of the periodic table.
Their outer shells are filled with electrons.
Which of the following properties are shared by many chemical reactions that occur in cells? Multiple select question. They tend to proceed toward equilibrium. They are not reversible. They often require a catalyst. They require energy.
They tend to proceed toward equilibrium. They often require a catalyst. They require energy.
In which of these conditions would an atom or ion be most stable? Multiple choice question. When it contains an equal number of protons and electrons When it participates in a hydrogen bond When it receives a donated electron When its outermost shell is occupied by its full complement of electrons
When its outermost shell is occupied by its full complement of electrons
A solution at pH 5 is said to be ______ because it contains more ______. Multiple choice question. basic; H+ ions than OH- ions acidic; OH- ions than H+ ions acidic; H+ ions than OH- ions basic; OH- ions than H+ ions
acidic; H+ ions than OH- ions
An ion that carries a net negative charge is a(n) ______. Multiple choice question. anion electron proton cation
antion
Within an atom's structure, electrons can be found ______. in cloudlike orbitals mixed with protons and neutrons in discrete, clearly defined orbits in the nucleus itself
in cloudlike orbitals
An element's atomic ______ is based on the protons and neutrons it contains, while an element's atomic ______ is based only on the number of protons.
mass; number
Compared with liquid water, ice has ______. Multiple select question. a less orderly arrangement of water molecules fewer hydrogen bonds between individual water molecules more hydrogen bonds between individual water molecules a more orderly arrangement of water molecules
more hydrogen bonds between individual water molecules a more orderly arrangement of water molecules
Phosphorus exists in several isotopes, including 31P and 32P. These are expected to have different ______.
neutrons
A hydrogen bond forms when a hydrogen atom with a partial _____ charge becomes electrically attracted to an electronegative atom with a partial _______ charge.
positive, negative
In the conversion of methane and oxygen to carbon dioxide and water, carbon dioxide is a(n) ______. enzyme product catalyst reactant
product
Atoms of different chemical elements can be differentiated based on the number of ______. neutrons in the nucleus orbitals in the outermost shell electrons in the outermost shell electrons in all shells protons in the nucleus
protons in the nucleus
An atom's atomic number is based on the number of ______ it contains. In an atom that is not in a chemical reaction, this number equals to the number of _______.
protons, electrons
Within an atom, particles with nearly equal mass are ______ and neutrons, while________ have a much smaller mass.
protons, electrons
To freeze water, energy is ______. Multiple choice question. added not a consideration released
released
A liquid that can dissolve substances is known as a(n)
solvent
As a result of the electron configuration of a water molecule, water is a great ____________ because water can break up and surround a ____________ , as long as it is not ____________ , dissolving it into solution. The reason water behaves in this manner is because the ____________ charge on the hydrogen end of the water molecule is attracted to the negative charge of a polar molecule, while the ____________ charge of the oxygen end of the water molecule is attracted to the positive side of a polar molecule.
solvent, solute, nonpolar, positive, negative
Chemical bonds can form among atoms due to the presence of unpaired _______ electrons.
valance
What occurs during all chemical reactions? Multiple choice question. Energy is converted to chemicals. Chemical bonds are broken or formed. Products are converted to reactants.
Chemical bonds are broken or formed.
Desceribe each bond: A: Covalent B: Ionic C: Hydrogen 1. Strong chemical bond due to the sharing of electrons 2.Bonds between charged molecules or portions of a molecule 3. Electrons are transferred between two atoms creating positively and negatively charged atoms, which are then attracted to one another. 4.Na+ + CI- -› NaCI 5. Bonds btwn hydrogen and oxygen atoms btwn a water molecule 6.Weak attraction between slightly charged parts of molecules, which are readily broken and reformed. 7.Bonds between water molecules.
1. A 2. C 3. B 4. B 5. A 6. C 7. C
____________ of carbon = 1 mole.
12g
Oxygen has eight protons, eight electrons, and eight neutrons. What is its atomic mass?
16
The chemical formula of glucose is C6H12O6. How many oxygen atoms are in one molecule of glucose? Include just the number in your answer.
6
Carbon has a total of ____________ electron(s), ____________ are in the valence shell, and ____________ are in the 1s orbital.
6,4,2
Nitrogen has a total of ____________ electron(s), ____________ are in the valence shell, and ____________ lie in the p orbitals.
7,5,3
According to the octet rule, many atoms are most stable when they have _____ electrons in their outermost shell.
8 valence
Oxygen has a total of ____________ electrons, ____________ are in the valence shell, and ____________ are in the p orbitals.
8,6,4
Here are three descriptions of the modern model of atomic structure. Which is the best? A central nucleus surrounded by cloudlike orbitals containing electrons A central nucleus surrounded by electrons traveling in clearly defined orbits A collection of positive and negative charges uniformly distributed throughout the atom
A central nucleus surrounded by cloudlike orbitals containing electrons
Why do hydrogen bonds connecting water molecules form between oxygen and hydrogen molecules?
A partially positive and partially negative atom pair is required for hydrogen bonds to form
Select all that apply Which of the following are common features of chemical reactions? Multiple select question. Chemical reactions require a source of energy. Chemical reactions proceed toward equilibrium. Many chemical reactions that occur in cells require catalysts. Many chemical reactions in living organisms take place in a watery environment. Chemical reactions cease when they reach equilibrium.
Chemical reactions require a source of energy. Chemical reactions proceed toward equilibrium. Many chemical reactions that occur in cells require catalysts. Many chemical reactions in living organisms take place in a watery environment.
Which of the following best describes a contemporary model of electron movement within atoms? Electrons all occupy the same orbital. Electrons move in different patterns depending on the number of atoms in the elements. Electrons move in very discrete, defined paths. Electrons move in orbitals, although their exact location cannot be precisely predicted in these orbitals.
Electrons move in orbitals, although their exact location cannot be precisely predicted in these orbitals.
T/F: A non-polar covalent bond is formed when two atoms of different electronegativities share electrons.
F: polar covalent
Which component of humans has the greatest percent of water?
Lungs
Pure water can ionize into which of the following? Multiple choice question. Positively charged hydroxide (OH+) ions and negatively charged protons (H-) Positively charged dihydroxide (H2+) ions and negatively charged oxygen ions (O-) Positively charged protons (H+) and negatively charged hydroxide (OH-) ions Negatively charged dihydroxide (H2-) ions and positively charged oxygen ions (O+)
Positively charged protons (H+) and negatively charged hydroxide (OH-) ions
A polar covalent bond is created when a-electrons transferred from one atom to another disrupt the balance between the two sides of the bond, making the bond very unstable. b-bonded atoms have an equal pull on the shared electron, so that the electron spends approximately equal amounts of time around each. c-bonded atoms have unequal pull on the shared electron, so that the electron spends more time around one atom than the other. d-electrons and protons are shared between atoms, creating a strong bond, which can only be broken with a large input of energy.
c: bonded atoms have unequal pull on the shared electron, so that the electron spends more time around one atom than the other.
Chemical reactions require a source of energy and also may require a substance called a(n) _____ that speeds up the reaction rate. Most chemical reactions proceed toward a state called ________, in which the rate of product formation equals the rate of reactant formation.
catalyst, equilibrium
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
One ____________ is approximately the mass of one proton or a hydrogen atom.
dalton
What happens to the pH of a solution when H+ ions are added to it?
decreases
