Chapter 2 Flashcards
Proton
positively-charged subatomic particle
center of an atom that contains protons and neutrons
nucleus
(chemistry)
substance made up of atoms of more than one element
compound
bond between charged ions
Ionic Bond
positively-charged subatomic particle
Proton
Base
substance that can accept hydrogen ion in solution
heat of vaporization
energy required to convert liquid to a gas
solution
solvent and dissolved solute mixture
hydrophobic
uncharged, nonpolar groups of atoms/molecules that have no affinity for water
- measure of a solution’s acidity/hydrogen ion concentration
- -log( [H+] )
pH
hydrophillic
having an affinity for water; polar
anion
negatively charged ion
energy
capacity to do work or to accomplish change in physical or chemical systems
orbital
region in space surrounding nucleus in which an electron is most likely to be found
acid
substance that can release a proton in solution
polar
having opposite electric charges at two ends
molecule
chemical substance consisting of two or more atoms joined by bonds or attractions
reactant
substance that enters into a chemical reaction
solvent
liquid in which solutes are dissolved to form a solution
Molecular Weight
sum of atomic weights in a molecule
electron
(def)
negatively charged subatomic particle
hydrogen bond
weak electrostatic bond between slightly-positive hydrogen atom and slightly-negative charge on a nearby atom
ion
electrically charged particle that forms when atom gains or loses electron(s)
van der Waals forces
weak attractions between atoms resulting from interactions between electons of one atom and the nucleus of another
van der Waals forces
(strength)
bonds that are about 1/4 as strong as hydrogen bonds
neuton
- neutrally-charged subatomic particle located in the nuclei of atoms
- molecular weight of approx. 1 amu
reversible reaction
chemical change that can occur in both forward and reverse direction
electron shell
region in which electrons orbit; surrounding atomic nucleus at fixed energy level
sum of an atom’s protons and neutrons
mass number
radioisotope
radioactive isotope
(e.g. carbon-14, hydrogen-3, tritium)
substance that can accept or release hydrogen ions to resist changes in pH
buffer
amount of energy required to raise 1 gram of a substance by 1 deg C
specific heat
isotope
atom containing same number of protons as shown in the periodic table, but differing in the number of neutrons within the nucleus
specific heat
amount of energy required to raise 1 gram of a substance by 1 deg C
compound
substance made up of atoms of more than one element
cohesion
tendency of molecules to stick together
element
substance that cannot be converted to a simpler substance
atomic number
- equivalent to the number of protons in an atom’s nucleus (equal to electrons around atom)
- determines chemical properties of atom
electronegativity
affinity of an atom to attract electrons when it occurs as part of a compound
mole
avogadro’s number of something
covalent bond
bond based on the (equal or unequal) sharing of electrons between two atoms
avogadro’s number
6.022 x 10^23
chemical bond
attractive force linking two atoms
pH
- measure of a solution’s acidity/hydrogen ion concentration
- -log( [H+] )
buffer
substance that can accept or release hydrogen ions to resist changes in pH
nucleus
(chemistry)
center of an atom that contains protons and neutrons
substance that can accept hydrogen ion in solution
Base
energy required to convert liquid to a gas
heat of vaporization
solvent and dissolved solute mixture
solution
uncharged, nonpolar groups of atoms/molecules that have no affinity for water
hydrophobic
radioactive isotope
(e.g. carbon-14, hydrogen-3, tritium)
radioisotope
solute
substance dissolved in a liquid to form a solution
mass number
sum of an atom’s protons and neutrons
having an affinity for water; polar
hydrophillic
negatively charged ion
anion
Ionic Bond
bond between charged ions
capacity to do work or to accomplish change in physical or chemical systems
energy
region in space surrounding nucleus in which an electron is most likely to be found
orbital
tendency of molecules to stick together
cohesion
substance that can release a proton in solution
acid
having opposite electric charges at two ends
polar
substance that cannot be converted to a simpler substance
element
chemical substance consisting of two or more atoms joined by bonds or attractions
molecule
substance that enters into a chemical reaction
reactant
- equivalent to the number of protons in an atom’s nucleus (equal to electrons around atom)
- determines chemical properties of atom
atomic number
liquid in which solutes are dissolved to form a solution
solvent
substance dissolved in a liquid to form a solution
solute
affinity of an atom to attract electrons when it occurs as part of a compound
electronegativity
sum of atomic weights in a molecule
Molecular Weight
avogadro’s number of something
mole
negatively charged subatomic particle
electron
(def)
bond based on the (equal or unequal) sharing of electrons between two atoms
covalent bond
weak electrostatic bond between slightly-positive hydrogen atom and slightly-negative charge on a nearby atom
hydrogen bond
positively charged ion
cation
electrically charged particle that forms when atom gains or loses electron(s)
ion
6.022 x 10^23
avogadro’s number
weak attractions between atoms resulting from interactions between electons of one atom and the nucleus of another
van der Waals forces
attractive force linking two atoms
chemical bond
bonds that are about 1/4 as strong as hydrogen bonds
van der Waals forces
(strength)
- neutrally-charged subatomic particle located in the nuclei of atoms
- molecular weight of approx. 1 amu
neuton
cation
positively charged ion
chemical change that can occur in both forward and reverse direction
reversible reaction
region in which electrons orbit; surrounding atomic nucleus at fixed energy level
electron shell
the (weighted) average mass numbers of a sample of atoms
atomic weight
atom containing same number of protons as shown in the periodic table, but differing in the number of neutrons within the nucleus
isotope
atomic weight
the (weighted) average mass numbers of a sample of atoms
Phosphorus has an atomic number of 15 and an atomic mass of 31. How many neutrons does phosphorus have?
A. 5
B. 16
C. 30
D. 31
E. 47
B
Particles having a net negative charge are called
A. electronegative
B. cations
C. anions
D. acids
E. bases
C
Which of the following correctly states an unusual property of water?
A. Water will not react with other atoms
B. Water’s solid state is denser than its liquid state.
C. Energy is not required to change water from a wolid to a liquid.
D. Little heat energy is needed to raise the temperature of water.
E. The hydrogen bonds between water molecules continually form and break.
E
Polar molecules
A. have bonds with an overall positive charge.
B. have bonds with an unequal distribution of electric charge.
C. must form ions in water solution.
D. have bonds with an equal distribution of electrical charge.
E. have bonds with an overall negative charge.
B
Covalent bond formation depends ont eh ability of atoms to
A. share electrons with other atoms.
B. donate electrons to other atoms.
C. receive electrons from other atoms.
D. both a and b
E. all of the above
A
The element with which of the following atomic numbers would be most stable?
A. 1
B. 3
C. 12
D. 15
E. 18
E
The role of a buffer is to
A. allow the pH of a solution to vary widely.
B. make a solution basic.
C. maintain pH homeostasis.
D. disrupt pH homeostasis.
E. make a solution more acidic.
C
Based on the symbol for iron (Fe) shown here, select the correct list of characteristics for iron.
A. Number of protons = 26; number of electrons = 29; number of neutrons = 29
B. Number of protons = 29; number of electrons = 26; number of neutrons = 26
C. Number of protons = 26; number of electrons = 26; number of neutrons = 55
D. Number of protons = 26; number of electrons = 26; number of neutrons = 29
E. Number of protons = 55; number of electrons = 55; number of neutrons = 26
D
The graph shown depicts a pH scale with the pH values of several substances indicated. Which of the following statements is false?
A. Distilled water (pH 7.0) has an equal concentration of H+ and OH– ions.
B. Baking soda (pH 9.0) has a higher concentration of H+ ions than black coffee (pH 5.0).
C. Milk of magnesia (pH 10.0) has a higher concentration of OH– ions than seawater (pH 8.0)
D. A solution with a lower pH has a higher concentration of H+ ions than a solution with a higher pH.
E. A solution with a higher pH has a higher concentration of OH– ions than a solution with a lower pH.
B
Which example shown (A–E) depicts the correct distribution of charge and hydrogen bonding between two water molecules?
A
B
C
D
E
A
The accompanying figure demonstrates the process of salt dissolving in water. Which of the following is not depicted?
A. Cations and anions
B. Ionic bonding
C. Hydrogen bonding
D. Solute dissolving in water
E. Hydrophobic interactions
E
In comparing solid water (ice) and liquid water, select the false statement from the following choices.
A. Liquid water is less dense than solid water.
B. Solid water has a crystalline structure.
C. Hydrogen bonds hold water molecules in a rigid state in solid water.
D. In solid water, each water molecule can be hydrogen-bonded to four other water molecules.
E. Hydrogen bonds continue to break and re-form in liquid water.
A
Consider the accompanying figure showing a hydrogen bond between two water molecules. Which of the following properties of water is not caused by this interaction?
A. High surface tension
B. Great cohesive strength
C. Low specific heat
D. Excellence as a solvent
E. High heat of evaporation
C
Consider the carbonic acid (H2CO3) buffer system depicted in the graph shown. In this system, the following reaction (H2CO3 → HCO3– + H+) is utilized to reduce the effect of adding acid. From the following choices, select the one that makes the following statement true: In this buffer system, HCO3– is _______, H2CO3 is _______, and _______ would predominate in the system, receiving zero units of base.
A. a base; an acid; HCO3–
B. a base; an acid; H2CO3
C. an acid; a base; HCO3–
D. an acid; a base; H2CO3
E. basic; acidic; H2CO3
This figure shows the radioisotope tritium. Which of the following statements regarding radioisotopes is false?
A. Radioisotopes differ from other isotopes in that they give off energy.
B. Radioisotopes can be used as a molecular “tag” for medical diagnostic purposes.
C. Radioisotopes are unstable because they contain more protons than nonradioactive forms of the same element.
D. Radioisotopes can be damaging to cells.
E. During the process of radioactive decay, radioisotopes can release energy in the form of alpha radiation.
C
The part of the atom that determines how the atom behaves chemically is the
A. proton.
B. election.
C. neutron.
D. innermost shell.
E. nucleus.
B
Which of the following statements about chemcial reactions is false?
A. They occur when atoms combine or change their bonding partners.
B. Reactions may go to completion.
C. The products of a chemica reaction are formed from the reactants.
D. Energy may be created or destroyed in a chemical reaction.
E. Changes in forms of energy may accompany chemical reactions.
D
Refer to the periodic table. Which of the following has the same number of outer-shell (valence) electrons as oxygen?
A. S
B. N
C. F
D. Na
E. Ca
A
Covalent Bonds: Given the shell configurations of hydrogen, carbon, and sulfur (shown), select a molecule from the list below that could not be formed
A. CH4
B. H–C=C–H
C. H3C–CH3
D. H–S–H
E. S=S
B
Oxygen forms ___ covalent bond(s), carbon forms ___, and hydrogen forms ___.
A. 1, 4, 1
B. 4, 4, 4
C. 2, 4, 0
D. 2, 4, 1
E. 2, 2, 2
D
The four most common elements in organisms are
A. Ca, Fe, H, O
B. H2O, C, H, O
C. C, O, H, N
D. N, C, Fe, H
E. P, H2O, C, O
C
Atomic and Mass Numbers I: This figure shows an atom of helium. Which of the following characteristics is true for helium?
A. Mass number = 4; atomic number = 2; net charge = 0
B. Mass number = 4; atomic number = 4; net charge = 0
C. Mass number = 4; atomic number = 2; net charge = +2
D. Mass number = 6; atomic number = 2; net charge = 0
E. Mass number = 6; atomic number = 2; net charge = +1
A
Chemical Reactions: Which of the following statements about the chemical reaction in the figure shown is false?
A. The reactants are to the left of the arrow.
B. The arrow represents the direction of the chemical reaction.
C. There is more potential chemical energy in the products than in the reactants.
D. The energy associated with this reaction could be measured in calories.
E. The difference in potential chemical energy in this reaction is released as heat and light.
C
A basic solution contains
A. more OH- ions than H+ ions.
B. more H+ ions than OH- ions.
C. the same number of OH- ions and H+ ions.
D. no OH- ions.
E. none of the above
A
Ions: Given the electron shell configuration and mass and atomic numbers for the sodium ion (Na+) shown here, select the correct choice below to complete the following sentence: The sodium ion has _______ protons in its nucleus, _______ electrons in its outermost shell, and it is a(n) _______.
A. 10; 0; anion
B. 11; 8; anion
C. 11; 0; anion
D. 10; 0; cation
E. 11; 8; cation
E
Given the electron shell configuration for sulfur (S) shown, select the correct choice below to complete the following sentence: Sulfur has _______ protons in its nucleus and requires _______ more electrons to complete its outer shell.
A. 8; 2
B. 8; 6
C. 16; 2
D. 16; 6
E. 16; 8
C
What determines if a molecule is polar, nonpolar, or ionic?
A. the number of protons
B. the bond distances
C. the differences in the electronegativities of the atoms
D. the ionic charges
E. the distance of the electrons from the nucleus
C
The three most abundant elements in a human skin cell are
A. calcium, carbon, and oxygen.
B. carbon, hydrogen, and oxygen.
C. carbon, hydrogen, and sodium.
D. carbon, nitrogen, and potassium.
E. nitrogen, hydrogen, and argon.
B
Which of the following statements about the isotopes of an element is not true?
A. They all have the same atomic number.
B. They all have the same number of protons.
C. They all have the same number of neutrons.
D. They all have the same number of electrons.
E. They all have identical chemical properties.
C
The atomic weight (atomic mass) of an element
A. equals the number of neutrons in an atom.
B. equals the number of protons in an atom.
C. equals the number of electrons in an atom.
D. equals the number of neutrons plus the number of protons.
E. depends on the relative abundances of its electrons and neutrons.
D
The atomic number of an element
A. equals the number of neutrons in an atom.
B. equals the number of protons in an atom.
C. equals the number of protons minus the number of neutrons.
D. equals the number of neutrons plus the number of protons.
E. depends on the isotope.
B
When table salt (NaCl) is added to water,
A. a covalent bond is broken.
B. an acidic solution is formed.
C. the Na+ and Cl− ions are separated.
D. the Na+ ions are attracted to the hydrogen atoms of water.
E. water molecules surround the Na+ (but not Cl−) ions.
C
Hydrophobic interactions
A. are stronger than hydrogen bonds.
B. are stronger than covalent bonds.
C. can hold two ions together.
D. can hold two nonpolar molecules together.
E. are responsible for the surface tension of water.
D
The reaction HCl → H+ + Cl− in the human stomach is an example of the
A. cleavage of a hydrophobic bond.
B. formation of a hydrogen bond.
C. elevation of the pH of the stomach.
D. formation of ions by dissolving an acid.
E. formation of polar covalent bonds.
D
Which of the following statements about water is not true?
A. It releases a large amount of heat when changing from liquid into vapor.
B. Its solid form is less dense than its liquid form.
C. It is the most effective solvent for polar molecules.
D. It is typically the most abundant substance in a living organism.
E. It takes part in some important chemical reactions.
A
The hydrogen bond between two water molecules arises because water is
A. polar.
B. nonpolar.
C. a liquid.
D. small.
E. hydrophobic
A
Which of the following statements about covalent bonds is not true?
A. A covalent bond is stronger than a hydrogen bond.
B. A covalent bond can form between atoms of the same element.
Cc. Only a single covalent bond can form between two atoms.
D. A covalent bond results from the sharing of electrons by two atoms.
E. A covalent bond can form between atoms of different elements.
C
positively-charged subatomic particle
Proton
nucleus
(chemistry)
center of an atom that contains protons and neutrons
compound
substance made up of atoms of more than one element
Ionic Bond
bond between charged ions
Proton
positively-charged subatomic particle
substance that can accept hydrogen ion in solution
Base
energy required to convert liquid to a gas
heat of vaporization
solvent and dissolved solute mixture
solution
uncharged, nonpolar groups of atoms/molecules that have no affinity for water
hydrophobic
pH
- measure of a solution’s acidity/hydrogen ion concentration
- -log( [H+] )
having an affinity for water; polar
hydrophillic
negatively charged ion
anion
capacity to do work or to accomplish change in physical or chemical systems
energy
region in space surrounding nucleus in which an electron is most likely to be found
orbital
substance that can release a proton in solution
acid
having opposite electric charges at two ends
polar
chemical substance consisting of two or more atoms joined by bonds or attractions
molecule
substance that enters into a chemical reaction
reactant
liquid in which solutes are dissolved to form a solution
solvent
sum of atomic weights in a molecule
Molecular Weight
negatively charged subatomic particle
electron
(def)
weak electrostatic bond between slightly-positive hydrogen atom and slightly-negative charge on a nearby atom
hydrogen bond
electrically charged particle that forms when atom gains or loses electron(s)
ion
weak attractions between atoms resulting from interactions between electons of one atom and the nucleus of another
van der Waals forces
bonds that are about 1/4 as strong as hydrogen bonds
van der Waals forces
(strength)
- neutrally-charged subatomic particle located in the nuclei of atoms
- molecular weight of approx. 1 amu
neuton
chemical change that can occur in both forward and reverse direction
reversible reaction
region in which electrons orbit; surrounding atomic nucleus at fixed energy level
electron shell
mass number
sum of an atom’s protons and neutrons
radioactive isotope
(e.g. carbon-14, hydrogen-3, tritium)
radioisotope
buffer
substance that can accept or release hydrogen ions to resist changes in pH
specific heat
amount of energy required to raise 1 gram of a substance by 1 deg C
atom containing same number of protons as shown in the periodic table, but differing in the number of neutrons within the nucleus
isotope
amount of energy required to raise 1 gram of a substance by 1 deg C
specific heat
substance made up of atoms of more than one element
compound
tendency of molecules to stick together
cohesion
substance that cannot be converted to a simpler substance
element
- equivalent to the number of protons in an atom’s nucleus (equal to electrons around atom)
- determines chemical properties of atom
atomic number
affinity of an atom to attract electrons when it occurs as part of a compound
electronegativity
avogadro’s number of something
mole
bond based on the (equal or unequal) sharing of electrons between two atoms
covalent bond
6.022 x 10^23
avogadro’s number
attractive force linking two atoms
chemical bond
- measure of a solution’s acidity/hydrogen ion concentration
- -log( [H+] )
pH
substance that can accept or release hydrogen ions to resist changes in pH
buffer
center of an atom that contains protons and neutrons
nucleus
(chemistry)
Base
substance that can accept hydrogen ion in solution
heat of vaporization
energy required to convert liquid to a gas
solution
solvent and dissolved solute mixture
hydrophobic
uncharged, nonpolar groups of atoms/molecules that have no affinity for water
radioisotope
radioactive isotope
(e.g. carbon-14, hydrogen-3, tritium)
substance dissolved in a liquid to form a solution
solute
sum of an atom’s protons and neutrons
mass number
hydrophillic
having an affinity for water; polar
anion
negatively charged ion
bond between charged ions
Ionic Bond
energy
capacity to do work or to accomplish change in physical or chemical systems
orbital
region in space surrounding nucleus in which an electron is most likely to be found
cohesion
tendency of molecules to stick together
acid
substance that can release a proton in solution
polar
having opposite electric charges at two ends
element
substance that cannot be converted to a simpler substance
molecule
chemical substance consisting of two or more atoms joined by bonds or attractions
reactant
substance that enters into a chemical reaction
atomic number
- equivalent to the number of protons in an atom’s nucleus (equal to electrons around atom)
- determines chemical properties of atom
solvent
liquid in which solutes are dissolved to form a solution
solute
substance dissolved in a liquid to form a solution
electronegativity
affinity of an atom to attract electrons when it occurs as part of a compound
Molecular Weight
sum of atomic weights in a molecule
mole
avogadro’s number of something
electron
(def)
negatively charged subatomic particle
covalent bond
bond based on the (equal or unequal) sharing of electrons between two atoms
hydrogen bond
weak electrostatic bond between slightly-positive hydrogen atom and slightly-negative charge on a nearby atom
cation
positively charged ion
ion
electrically charged particle that forms when atom gains or loses electron(s)
avogadro’s number
6.022 x 10^23
van der Waals forces
weak attractions between atoms resulting from interactions between electons of one atom and the nucleus of another
chemical bond
attractive force linking two atoms
van der Waals forces
(strength)
bonds that are about 1/4 as strong as hydrogen bonds
neuton
- neutrally-charged subatomic particle located in the nuclei of atoms
- molecular weight of approx. 1 amu
positively charged ion
cation
reversible reaction
chemical change that can occur in both forward and reverse direction
electron shell
region in which electrons orbit; surrounding atomic nucleus at fixed energy level
atomic weight
the (weighted) average mass numbers of a sample of atoms
isotope
atom containing same number of protons as shown in the periodic table, but differing in the number of neutrons within the nucleus
the (weighted) average mass numbers of a sample of atoms
atomic weight
