Chapter 2: The Chemical Basis of Life I QUESTIONS

अब Quizwiz के साथ अपने होमवर्क और परीक्षाओं को एस करें!

Ionic bond

Bond between a cation and an anion

Energy

The capacity to affect change or do work.

What type(s) of compound(s) minimize pH fluctuations in the fluids of living organisms?

buffer buffering agent

The amount of solute (in grams) dissolved in a given volume of solution is the solution's

concentration

High specific heat, surface tension, and cohesion are several properties of water involving __________ bonds

hydrogen

acid rain can _________ the pH of water entering the roots of plants.

lower

Solutes dissolved in a solvent form a(n)

solution

acidic

Contains more H+ than OH- ions

alkaline

Contains more OH- than H+ ions

heat of vaporization

The heat energy required to convert 1 mole of a substance from liquid to gas

_______ which is the vaporization of water, helps animals to dissipate body heat.

evaporation

In ice, H2O molecules move ______ slowly than in water, and consequently hydrogen bonds are broken ______ frequently.

more, less

The nucleus of an atom has a net ______ charge.

positive

To freeze water, energy is

released

structural formulas

represent covalent bonds by a line indicating a pair of electrons.

An electron _____ contains one or more electron orbitals

shell

The concentration of a liquid is defined as the amount of ______ dissolved in a unit volume of solution.

solute

Substances dissolved in liquid are known as

solutes

A base will absorb _______ ions in solution

Hydrogen

Which of the following changes in the physical state of water require the input of energy?

Changing from solid to liquid Changing from liquid to gas

Which of the following statements are true of a polar covalent bond?

The atoms in the bond differ in electronegativity. The two atoms in the bond share the electrons unequally.

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The heat energy that must be withdrawn or released from a substance to convert it from liquid to solid

What is the molarity of a solution?

The number of moles of solute in 1 L

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 substance that releases hydrogen ions into solution is called a(n)

acid

If you add H+ ions 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

The hydrogen bonds between water molecules form between

an oxygen atom on one water molecule and a hydrogen atom on a second water molecule.

In living organisms, most chemical reactions take place in ______ solutions.

aqueous

Molecules with covalent bonds

are flexible within certain limits.

The fundamental unit of matter is the

atom

Matter is composed of functional units called _____ two or more of which bonded together form a(n) _____.

atoms, molecule

Electronegativity is the ability of an atom to

attract electrons

A substance that absorbs hydrogen ions in solution is called a(n)

base

nonpolar covalent bond

bond in which two atoms share electrons equally

polar covalent bond

bond in which two atoms share electrons unequally

Hydrolysis reactions

break apart molecules via water.

Living organisms minimize changes in their internal pH using compounds called

buffers

The _____ of an atom is a measure of its ability to attract electrons when in a bond with another atom.

electronegativity

The stability of atoms is greatest when their outer shells are filled with

electrons

Hydrochloric acid is considered an acid because it releases ___________ ions into solution.

hydrogen

What type of bond is indicated by a dotted line?

hydrogen bond

In a _________ reaction, water is used to break apart another molecule.

hydrolysis

Within an atom's structure, electrons can be found

in cloud-like orbitals.

Electronegativity differences between atoms dictate the polarity of molecules by

influencing whether covalent bonds are polar or nonpolar.

An atom with a net electric charge is called a(n)

ion

The following molecules are likely to dissolve easily in water if they contain which type(s) of bonds?

ionic bonds polar covalent bonds

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

When mixed with water, amphipathic molecules may aggregate into spheres called

micelle

The number of moles of a solute dissolved in one liter of solution is the solution's

molarity

The sum of the atomic masses of all atoms in a molecule is equal to the molecule's __________ mass

molecular

pH is defined as the ______ __________ to the base 10 of the _________ ion concentration.

negative logarithm, H+

Isotopes of an element differ from one another in the number of ___ they contain.

neutrons

What part of an amphipathic molecule would be oriented toward the center of a micelle?

nonpolar region

Colligative properties depend on the ______ dissolved in a solution.

number of particles

According to the ____ rule, atoms tend to be most stable when their outer shells are filled; this can be accomplished by gaining, losing, or sharing _____.

octet, electrons

How many types of atoms can be found in a single element?

only one

The region of space in which there is a high probability of finding an electron is called a(n):

orbital

The polar groups of a micelle are oriented toward the ______, while its nonpolar groups are oriented toward the _______.

outside, inside

A(n) ______ bond is formed when two atoms of different electronegativities share electrons.

polar covalent

In a micelle, which portion of the amphipathic molecules are oriented toward the surface of the sphere?

polar region

Pure water can ionize into

positively charged protons (H+) and negatively charged hydroxide (OH-) ions.

In a water molecule (H2O), each hydrogen atom has a partial ____ charge, and the oxygen atom has a partial __________ charge.

postive, negative

Atoms of different chemical elements can be differentiated based on the number of

protons in the nucleus.

Within an atom, ____ and neutrons have nearly equal masses, while ____ have a much smaller mass.

protons, electrons

What are the three subatomic particles?

protons, neutrons, electrons

Which of the following are considered subatomic particles?

protons, neutrons, electrons

A liquid that can dissolve substances is known as a(n)

solvent

The attraction between molecules at the surface of a liquid is called

surface tension

What happens to the pH of a solution when H+ ions are added to it?

the pH decreases

Cohesion of water is defined as

the property of water molecules attracting each other.

The molecular mass of a molecule is equal to

the sum of the atomic masses of all atoms in the molecule.

All living organisms require ______ elements. These elements are present in extremely small quantities but are still essential for normal growth and function.

trace

A single orbital can contain a maximum of _____ electrons.

two

Electrons in an atom's outermost energy shells are called ______ electrons.

valence

Unpaired ____ electrons enable chemical bonds to form among atoms.

valence

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

About 60-70 % of human body weight is composed of ___________ which is a vital component of living organisms.

water

An aqueous solution is one in which the solvent is

water

Most chemical reactions in living organisms involve reactants and products that are dissolved in

water

When water ionizes, it produces what ions?

H+ OH-

Which of the following is the best description of the modern model of atomic structure?

A central nucleus surrounded by cloudlike orbitals containing electrons.

Polar covalent bond

A covalent bond in which the atoms share electrons unequally

Which of the following contributes to water's stability in a liquid state?

A high heat of fusion A high heat of vaporization

Hydrogen bond

Bond between atoms with partial positive and partial negative charges

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?

Cohesion High specific heat High heat of vaporization Adhesion Surface tension

neutral pH

Contains equal numbers of OH- and H+ ions

Atomic mass is measured in units of

Da (Daltons).

Which 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.

Select all of the following molecules that are predicted to easily dissolve in water.

Ions that carry full electric charges. Carbohydrates that contain -OH groups.

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

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

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

Structural formulas depict molecules with what type of bonds?

covalent

One ______ equals one 12th the mass of a carbon atom.

dalton

Because exercise produces lactic acid, it may

decrease the pH of body fluids.

If an atom gains or loses a(n) ________ it acquires a net electrical charge and becomes an ion.

electron

What is a likely predictor of how many covalent bonds an atom can form?

electron configuration in the outermost shell


संबंधित स्टडी सेट्स

Chapter 14 ( musculoskeletal imaging, breast, and superficial structures)

View Set

Chapter 1 : Taking a Computer Apart & Putting Back Together

View Set

CH.3 SUPPLY AND DEMAND AND MARKET EQUILIBRIUM

View Set

History Sepoy rebellion and Opium Wars quest

View Set

15.6 Quiz: Consumer Health and Aging

View Set

Emergency Management Test 1 Terms

View Set