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