question

condensed

answer

Solid and liquid states are known as the __ states

question

more

answer

Solid and liquid states are __ similar to each other than they are to the gas state

question

gas

answer

In the __ state, constituent particles – atoms or molecules – are separated by large distances and do not interact with each other very much

question

condensed

answer

In the _ states, constituent particles are close together and exert moderate to strong attractive forces on one another

question

Intermolecular forces

answer

__ – attractive forces that exist between all molecules and atoms

question

condensed

answer

Intermolecular forces are responsible for the very existence of __ states

question

magnitude

answer

The state sample of matter – solid, liquid, or gas – depends on __ of intermolecular forces between constituent particles, relative to the amount of thermal energy in the sample

question

thermal energy

answer

The molecules and atoms composing matter are in constant random motion that increases with increasing temperature. The energy associated with this motion is called __

question

gaseous

answer

When thermal energy is high relative to intermolecular forces, matter tends to be __

question

liquid or solid

answer

When thermal energy is low relative to intermolecular forces, matter tends to be _

question

greater

answer

Densities of the solid and liquid states are much __ than the densities of the gas state

question

more

answer

Solid and liquid states are _ similar in density and molar volume to one another than they are to the gas state

question

less

answer

For water, the solid is slightly __dense than the liquid. This is atypical behavior

question

denser

answer

Most solids are slightly __ than their corresponding liquids because the molecules move closer together upon freezing

question

movement

answer

Major difference between liquids and solids is the freedom of __ of the constituent molecules or atoms

question

thermal

answer

Even though the atoms or molecules in a liquid are in close contact, __ energy partially overcomes the attractions between them, allowing them to move around one another

question

solid

answer

The atoms or molecules in a __ are virtually locked in their positions, only vibrating back and forth about a fixed point

question

free

answer

Liquids assume the shape of their containers because the atoms or molecules that compose liquids are __ to flow (or move around one another)

question

Liquids

answer

__ are not easily compressed because the molecules or atoms that compose them are already in close contact – they cannot be pushed much closer together

question

gas

answer

The molecules in a __ have a great deal of space between them and are easily compressed

question

Solids

answer

__ have a definite shape because the molecules or atoms that compose solids are fixed in place – each molecule or atom merely vibrates about a fixed point

question

cannot

answer

Solids have a definite volume and generally __ be compressed because the molecules or atoms composing them are already in close contact

question

crystalline

answer

Solids may be __, in which case the atoms or molecules that compose them are arranged in a well-ordered 3-D array

question

amorphous

answer

Solids may be __, in which case the atoms or molecules that compose them have no long-range order

question

temperature, pressure, or both

answer

We can transform one state of matter to another by changing the __

question

denser

answer

Increases in pressure favor the __ state, so increasing the pressure of a gas sample results in a transition to the liquid state

question

does not

answer

When something changes states its chemical composition __ change

question

state – solid, liquid, or gas –

answer

The strength of the intermolecular forces between the molecules or atoms that compose a substance determine its __ at a given temperature

question

liquids and solids
gases

answer

At room temperature, moderate to strong intermolecular forces tend to result in __ (high melting and boiling points) and weak intermolecular forces tend to result in __ (low melting and boiling points)

question

charges, partial charges, and temporary charges

answer

Intermolecular forces originate from the interactions between __ on molecules (or atoms and ions), much as bonding forces originate from interactions between charged particles in atoms

question

Coulomb’s law

answer

According to __, the potential energy (E) of two oppositely charged particles (with charges q¬¬1 and q2) decreases (becomes more negative) with increasing magnitude of charge and with decreasing separation (r)

question

decreases

answer

Protons and electrons are attracted to each other because their potential energy __ as they get closer together

question

potential energy

answer

Molecules with partial or temporary charges are attracted to each other because their __ decreases as they get closer together

question

bonding

answer

Intermolecular forces, even the strongest ones, are generally much weaker than __ forces

question

large charges

answer

Bonding forces are the result of __ (the charges on protons and electrons) interacting at very close distances

question

smaller charges

answer

Intermolecular forces are the result of __ interacting at greater distances

question

dispersion forces, dipole-dipole forces, hydrogen bonding, and ion-dipole forces

answer

what are the different types of intermolecular forces

question

Dispersion

answer

__ forces can potentially occur in all substances

question

Ion-dipole

answer

__ forces occurs only in mixtures

question

London force

answer

The one intermolecular force present in all molecules and atoms is the dispersion force (also called the __)

question

electron distribution

answer

Dispersion forces are the result of fluctuations in the __ within molecules or atoms

question

instantaneous dipole or a temporary dipole

answer

The electrons in an atom or molecule may, at any one instant, be unevenly distributed. Having the electrons be unevenly distributed around the nucleus will give the different sides of an atom or molecule slightly negative or positive charges. This fleeting change separation is called an __

question

neighboring

answer

An instantaneous dipole on one atom induces an instantaneous dipole on its __ atoms because the positive end of the instantaneous dipole attracts electrons in the neighboring atoms

question

dispersion force

answer

The neighboring atoms then attract one another – the positive end of one instantaneous dipole attracting the negative end of another. This attraction is the __

question

polarize

answer

The magnitude of the dispersion force depends on how easily the electrons in the atom or molecule can more or __ in response to an instantaneous dipole, which in turn depends on the size (or volume) of the electron cloud

question

greater dispersion force

answer

A larger electron cloud results in a __ because the electrons are held less tightly by the nucleus and therefore polarize more easily

question

increases

answer

The dispersion force __ with increasing molar mass because molecules or atoms of higher molar mass generally have more electrons dispersed over a greater volume

question

increasing

answer

As the molar masses and electron cloud volume increases, the greater the dispersion force which results in __ boiling points

question

molecular shape

answer

molar mass alone does not determine the magnitude of the dispersion force. __ can also determine magnitude of the dispersion force

question

polar

answer

The dipole-dipole force exists in all molecules that are __

question

dipole-dipole

answer

Polar molecules have permanent dipoles that interact with the permanent dipoles of neighboring molecules. The positive end of one permanent dipole attracts the negative end of another; this attraction is the __ force

question

higher

answer

Polar molecules, therefore have __ melting and boiling points than nonpolar molecules of similar molar mass

question

nonpolar

answer

All molecules (including polar ones) have dispersion forces, but polar molecules have, in addition, dipole-dipole forces. Polar molecules have a raised melting and boiling points relative to __ molecules because of the additional attractive force (dipole-dipole forces)

question

increase

answer

Boiling points __ with increasing dipole moment

question

miscibility

answer

The polarity of molecules composing liquids is also important in determining the __ of liquids

question

Miscibility

answer

_ – the ability to mix without separating into two states

question

are
are not

answer

Polar liquids __ miscible with other polar liquids but __ miscible with nonpolar liquids

question

hydrogen bonding

answer

Polar molecules containing hydrogen atoms bonded directly to small electronegative atoms – most importantly fluorine, oxygen, or nitrogen – exhibit an intermolecular force called __

question

F, O, or N

answer

The large electronegativity difference between hydrogen and any of these electronegative elements causes the hydrogen atom to have a fairly large partial positive charge (g+) within the bond, while the __ atom has a fairly large partial negative charge (g-)

question

hydrogen bonding

answer

Since these atoms are quite small, the H atom on one molecule can approach the F, O, or N atom on an adjacent molecule very closely. This results in a strong attraction between the H atom on one molecule and the F, O, or N on its neighbor, an attraction called __

question

WITHIN
BETWEEN

answer

Chemical bonds occur between individual atoms __ a molecule, whereas hydrogen bonds are intermolecular forces that occur __ molecules

question

stronger

answer

Hydrogen bonds are __ than dipole-dipole forces and dispersion forces

question

higher

answer

Substances composed of molecules that form hydrogen bonds have __ melting and boiling points than substances composed of molecules that do not form hydrogen bonds

question

ionic

answer

Ion-dipole force occurs when an __ compound is mixed with a polar compound; it is especially important in aqueous solutions of ionic compounds

question

Ion-dipole

answer

__ forces are the strongest of the types of intermolecular forces

question

Surface tension

answer

__ – the tendency of liquids to minimize their surface area

question

less

answer

The molecule at the surface has relatively fewer neighbors with which to interact and is therefore inherently __ stable – has higher potential energy – than those in the interior

question

lower

answer

Attractive interactions with other molecules __ potential energy

question

requires

answer

In order to increase the surface area of the liquid, molecules from the interior have to be moved to the surface, and, since molecules at the surface have a higher potential energy than those in the interior, this movement __ energy

question

minimize

answer

liquids tend to __ their surface area

question

surface tension

answer

The __ of a liquid is the energy required to increase the surface area by a unit amount

question

decreases

answer

Surface tension __ as intermolecular forces decrease

question

viscosity,

answer

the resistance of a liquid to flow

question

poise (P)

answer

Viscosity is measure in a unit called the __, defined as 1 g/cm x s

question

stronger

answer

Viscosity is greater in substances with _ intermolecular forces because if molecules are more strongly attracted to each other, they do not flow around each other as freely

question

molecular shape

answer

Viscosity also depends on _, increasing in longer molecules that can interact over a greater area and possibly become entangled

question

molar mass
length

answer

Notice the increase in viscosity with increasing __ (and therefore increasing magnitude of dispersion forces) and with increasing __ (and therefore increasing potential for molecular entanglement)

question

temperature

answer

Viscosity also depends on __because thermal energy partially overcomes the intermolecular forces, allowing molecules to flow past each other more easily

question

less

answer

Nearly all liquids become __ viscous as temperature increases

question

cohesive
adhesive

answer

the attraction between molecules in a liquid, called __ forces, and the attraction between these molecules and the surface of the tube, called __ forces

question

spread out
stay together

answer

The adhesive forces cause the liquid to __ over the surface of the tube, while the cohesive forces cause the liquid to __

question

greater

answer

If the adhesive forces are greater than the cohesive forces, the attraction to the surface draws the liquid up the tube and the cohesive forces pull along those molecules not in direct contact with the tube walls

question

smaller

answer

If the adhesive forces are __ than the cohesive forces, the liquid does not rise up the tube at all (and in fact will drop to a level below the level of the surrounding liquid)

question

Meniscus

answer

__ = curved shape of a liquid surface within a tube

question

Vaporization

answer

__ – the process by which thermal energy can overcome intermolecular forces and produce a state change from liquid to gas

question

energy

answer

The higher the temperature, the greater the average __ of the collection of molecules

question

thermal

answer

At any one time, some molecules would have more __ energy than the average and some would have less

question

vaporization

answer

transition from liquid to gas to called __

question

condensation

answer

transition from gas to liquid is called

question

vaporization

answer

if we increase the temperature of the water within the beaker, the shift in the energy distribution to higher energies will make it to where more molecules now have enough energy to break free and evaporate, so __ occurs more quickly

question

more

answer

if we spill the water on the table/floor, the same amount of water is now spread over a wider area, resulting in more molecules at the surface of the liquid. Since molecules at the surface have the greatest tendency to evaporate – because they are held less tightly – vaporization also occurs __ quickly

question

temperature

answer

substances with weaker intermolecular forces allow more molecules to evaporate at a given __, again increasing the rate of vaporization

question

volatile

answer

liquids that vaporize easily = __

question

nonvolatile

answer

liquids that do not vaporize easily = __

question

increases

answer

The rate of vaporization __ with increasing temperature

question

increases

answer

The rate of vaporization __ with increasing surface area

question

decreasing

answer

The rate of vaporization increases with __ strength of intermolecular forces

question

endothermic

answer

Vaporization is an _ process; it takes energy to vaporize the molecules in a liquid

question

exothermic

answer

condensation is __ – heat is released when a gas condenses to a liquid

question

heat of vaporization (?Hvap)

answer

The amount of heat required to vaporize one mole of a liquid to a gas is its __

question

positive

answer

The heat of vaporization is always __ because the process is endothermic – energy must be absorbed to vaporize a substance

question

somewhat

answer

The heat of vaporization is __ temperature dependent

question

same amount

answer

When a substance condenses from a gas to a liquid, the __ of heat is involved, but the heat is emitted rather than absorbed

question

exothermic

answer

The sign of ?H when a gas condenses from a gas to a liquid is negative because the process is __

question

Dynamic equilibrium

answer

__: rate of evaporation = rate of condensation

question

condensation

answer

As the rate of concentration (or partial pressure) of gaseous water molecules increases, the rate of __ also increases

question

constant

answer

As long as water remains at a __ temperature, the rate of evaporation remains constant

question

vapor pressure

answer

The pressure of a gas in dynamic equilibrium with its liquid is called its __

question

temperature

answer

The vapor pressure of a particular liquid depends on the intermolecular forces present in the liquid and the __

question

volatile

answer

Weaker intermolecular forces result in __ substances with high vapor pressures because the intermolecular forces are easily overcome by thermal energy

question

low

answer

Strong intermolecular forces result in nonvolatile substances with __ vapor pressures

question

return

answer

A liquid in dynamic equilibrium with its vapor is a balanced system that tends to __ to equilibrium if disturbed

question

Le Chatelier’s principle

answer

If the pressure above a liquid-vapor system in equilibrium is decreased, some of the liquid evaporates, restoring the equilibrium pressure. If the pressure is increased, some of the vapor condenses, bringing the pressure back down to the equilibrium pressure

question

falls

answer

When a system in dynamic equilibrium has an increase in volume, the vapor pressure __. More gas vaporizes so that pressure is restored, and dynamic equilibrium is restored

question

rises

answer

When a system in dynamic equilibrium has a decrease in volume, the vapor pressure __. More gas condenses so that pressure is restored, and dynamic equilibrium is restored

Exam I – Chemistry – Flashcards

Unlock all answers in this set

Haven't found what you were looking for?

Search for samples, answers to your questions and flashcards