Unit 9: Phases of Matter
STP
1 atm and 273 K
which of the gases has the largest volume at STP
10 g He
manometer
A device used to measure the pressure of a sample of gas in a container (internal pressure).
Solid
A form of matter that has a definite shape and volume, not easily compressible, dense
Boyle's Law
A gas law that states that the pressure exerted by a gas (of a given mass, kept at a constant temp), is inversely proportional to the volume occupied by it.
Temperature
A measure of how hot (or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object. 273 K or 0 C at STP
_____________________ is a graph that shows in which phase a substance exists under different conditions of temperature and pressure
A phase diagram
liquid
A state of matter that has a definite volume but no definite shape. very dense, not easily compressible
Volume
Amount of space occupied by an object
barometer
An instrument that measures atmospheric pressure
Equal volume of gases at the same temp and pressure contain equal numbers of particles
Avogadro's Law
The vol. of a given amount of gas held at a constant temperature varies inversely with the pressure
Boyle's Law
the vol of a given mass of gas is directly proportional to its kelvin temperature at a constant pressure.
Charles
Temperature, pressure, and volume are related for a fixed amount of gas
Combined Gas Law
The sum of the partial pressure of the gases in a container is equal to the total pressure of all of the gases in the container
Dalton's Law
________________________ states that the total pressure of a mixture of gases is equal to the sum of the pressures of each gas in the mixture.
Dalton's Partial Pressure
Avogadro's Law
Equal volumes of all gases at the same temp. and pressure have the same number of molecules.
Which of the following expresses Avogadro's principle? -STP stands for standard temperature and pressure -One mole of any gas will occupy a certain volume at STP -The molar volume of a gas is the volume that one mole occupies at STP -Equal volumes of gases at the same temperature and pressure contain equal numbers of particles
Equal volumes of gases at the same temperature and pressure contain equal numbers of particles
Standard pressure is at 298K
F; 273 K
the ideal gas equation will only give correct values if the temperature is expressed in degrees.
F; Kelvin.
air bas are used as safety devices in cars because air can not be compressed
F; can
the number of moles of a gas is inversely proportional to its volume at STP
F; directly
according to the kinetic molecular theory, the collisions between gas particles are 100 percent elastic
F; ideal gas particles
real gases behave like ideal gases except at very high temperatures.
F; low
mos gases are made up of single atoms
F; molecules
as more particles are added to a container, there are fewer collisions because the particles don't go as fast.
F; more
oxygen is diatomic and under similar condition its volume is twice that of monatomic helium
F; same as
solids do not flow because the attractive forces between their particles are weaker than those in liquid or gases.
F; stronger
the pressure of a gas is simply a measure of the kinetic energy of the gas particles
F; temp.
pressure
Force per unit area. The SI unit is Pascal (Pa), atm, or kPa
the pressure of a given mass of gas varies directly with the kelvin temperature when the volume remains constant
Gay-Lussacs
At a constant temperature and pressure the rate of effusion of a gas is inversely proportional to the square root of its molar mass
Graham's Law of Dif/Effusion
which of the following has properties that are most similar to ideal gas? - N2 - O2 -He -Xe
He
covalent network solids
High Melting Point, Hard, Nonconducting atoms such as carbon and silicon. - are formed by networks or chains of atoms or molecules held together by covalent bonds. -form 3 solids- diamond, graphite, and buckminsterfullerene. carbon is allotrope
The physical behavior of an ideal gas can be expressed in terms of the pressure, colume, temperature, and number of moles of gas present.
Ideal Gas Law
R represents the relationship among, pressure, volume, temperature, and number of moles of gas present
Ideal gas constant
One mole of any gas will occupy a volume of 22.4 L at STP
Molar Volume
dipole-dipole attraction
The attractive force between the positively charged end of one polar molecule and the negatively charged end of another polar molecule. ex: when hydrogen-chloride gas molecules approach, the partially positive hydrogen atoms in one molecule is attracted to the partially negative chlorine atom in another molecule
relate vapor pressure to boiling point
The normal boiling point is the temperature in which the vapor pressure of a liquid becomes equal to atmospheric pressure. If the intermolecular forces are small, the liquid has a high vapour pressure. Little heat energy will have to be added to separate the molecules, so the boiling point will be low.
Gay-Lussac's Law
The pressure of a given mass of gas varies directly with the absolute temp of the gas when the volume remains constant
Charles' Law
The volume occupied by a fixed amount of gas is directly proportional to its absolute temp, if the pressure remains constant.
A "falling" barometer means that atmospheric pressure is decreasing
True
Standard atmospheric pressure is 760 mmHg
True
Gas
a form of matter that does not have a definite volume or shape, not dense easily compressible
Viscosity
a measure of the resistance of a liquid to flow. the viscosity of a liquid is determined by the type of intermolecular forces in the liquid, the size, and shape of the particles and the temp.
ideal gas
a theoretical gas which fits into the equation PV=nRT. They abide by all gas laws regardless of the pressure of temp; however they do not exist. - they occupy no vol., exert no attractive forces; their collisions are purely elastic. - pressure is much greater since they lack the attractive forces which hold the particles back.
The equation for the combined gas law can be used instead of which of the following equations? Boyle's law Charles' law all of these Gay-Lussac's law
all of these
triple point
all three phases are in equilibrium
The variable that stays constant when using the combined gas law is
amount of gas
intramolecular forces
an attractive forces that hold particles together, within.
ion-dipole attraction
an electrical attraction between an ion and a polar molecule
amorphous solid
any non crystalline solid in which the atoms and molecules are not organized in a definite lattice patter. ex: rubber, plastic, gels,
the solid phase of a compound has definite shape and volume because its particles
are held together by strong intermolecular forces
dispersion forces
attractions between molecules caused by the electron motion on one molecule affecting the electron motion on the other through electrical forces; these are the weakest interactions between molecules
The temperature at which the vapor pressure of a liquid equals the external or atmospheric pressure is called its ______________________________
boiling point
kinetic energy
can be transferred between colliding particles, but total KE doesn't change energy of gas particles: mass and velocity determine KE.
Combined Gas Law
combines the 3 laws: Boyles, Charles, Gay-Lussacs Law. It states that the ratio of the product of pressure and volume and the absolute temp of a gas is equal to a constant.
An air mattress springs back to its original shape after being pressed
compressibility
metal
consist of metal cations surrounded by a "sea" of mobile valence electrons. Variable Hardness and Melting Point (depending upon strength of metallic bonding), Conducting
A solid whose atoms, ions, or molecules are arranged in an orderly, geometric, three-dimensional structure is called __________________________
crystalline
an inflated balloon is placed in a refrigerator. the volume..
decreases
compressed air in a scuba tanks cools off when a scuba diver swims at deeper levels. the pressure in the tank
decreases
The process by which a substance changes from a gas or vapor to a solid without first becoming a liquid is called _________________________________
deposition
Kinetic Molecular Theory
describes the behavior of gases in terms of particles in motion; makes several assumptions about size, motion, and energy of gas particles
the color of a gas is uniform throughout the bottle containing it.
diffuses through other gases
________________________ is the movement of one material through another from high concentration to low concentration.
diffusion
Charles's Law explains the relationship between the temperature and volume of a gas. Which graph represents this relationship?
direct straight relationship
Which intermolecular force depends on the formation of temporary dipoles (polarity)?
dispersion forces
real gases exhibit most nearly ideal
during high temperatures and low pressures.
real gases exhibit least like ideal
during low temperatures and high pressures
if carbon dioxide rather than oxygen is the gas used in an experiment under comparable conditions, there will be a change in
effusion rate
Collisions between gas particles in which no kinetic energy is lost are said to be ______________________
elastic
a car is supported on a "cushion of air."
exerts pressure
A bicycle tire inflates when you pump air into a valve on one side
fills container
Two 500 ml flasks contain gas at STP. Flask A contains carbon monoxide and carbon dioxide in Flask B, which is true
flask A has less mass, but the same number of particles as B
which of the following is the best definition of pressure
force per unit area
intermolecular forces
forces of attraction are between or among. These forces can hold together identical particles. They are weaker than intramolecular forces involving bonding.
a balloon filled with air weighs more than an empty balloon
has mass
the molecules of an idea gas are assumed to
have elastic collisions
Which of the following is a gas-gas behavior relationship? - hydrogen gas is cooled and its pressure increases - nitrogen gas is placed in a container and the molecules settle to the bottom - oxygen gas is compressed and its temperature increases - helium gas is heated and its volume increases
helium gas is heated and its volume increases
which of the following would indicate the strongest intermolecular forces in a liquid
high boiling point
Martha and her father often skip stones across a pond. What type of intermolecular force creates the surface tension that allows the stones to skip?
hydrogen bonding
which of the following intermolecular forces of attraction is the strongest
hydrogen bonding
Physicians can use liquid nitrogen to freeze and destroy warts and other skin growths. Knowing the assumptions of the universal gas law (KMT), this should surprise you most because
if a gas can liquefy, that would imply that gases experience intermolecular forces
a person sits on an air mattress. the pressure
increases
a piston in an engine compresses the gas into smaller volume. The pressure ...
increases
additional gas is added to a soccer ball. the pressure...
increases
dry ice is sealed in a plastic bag. as the temperature increases the amount of gas present in the bag...
increases
the volume of an inflated balloon increases when the amount of gas in the balloon...
increases
A leftover hamburger patty is sealed in a plastic bag and placed in the refrigerator. What happens to the volume of the air in the bag?
it decreases
An aerosol can of air freshener is sprayed into a room. What happens to the pressure of the gas if its temperature stays constant?
it decreases
The room temperature increases from 20oC to 24oC. What happens to the pressure inside the cylinder of oxygen contained in the room?
it increases
The volume of air in human lungs increases before it is exhaled. What happens to the temperature of the air in the lungs to cause this change, assuming pressure stays constant?
it increases
What happens to the pressure of a gas in a light bulb a few minutes after the light is turned on?
it increases
During evaporation, certain liquid molecules become vapor molecules because they have greater than average _____________________________.
kinetic energy
The model describing the behavior of gases in terms of particles in motion is
kinetic molecular theory
Ideal gas law
law that describes the relationships between the measurable properties of an ideal gas. the law states that PV=nRT.
Which of the following has the highest density? water vapor liquid water steam ice
liquid water
The temperature at which a crystalline solid becomes a liquid is its ___________________________
melting point
molecular solid
molecules are held together by dispersion forces, dipole-dipole forces or hydrogen bonds. tend to be soft, low melting, and easily vaporized. most not solid at room temp. nonconductors of heat and electricity. ex: H2 CO2
elastic collision
no kinetic energy is lost.
Which of the following is NOT a characteristic of liquids? no significant attraction between particles more dense than gases less fluid than gases exhibits viscosity
no significant attraction between particles
what variable is mentioned in the ideal gas law that is assumed to be constant in the other gas laws.
number of moles
Which of these decreases as a given volume of gas increases? number of gas particles pressure temperature kinetic energy
pressure
_________________________ is force per unit area
pressure
Boyle's law relates _____________________________________________________ amount of gas are held constant.
pressure and volume if the temperature and
The diffusion of gases can best be explained by
random motion
What happens to the pressure of the gas in an inflated expandable balloon if the temperature is increased?
remains the same
real gas exert _________ attractive forces, it does not behave according to the assumption of kinetic-molecular theory
small
ionic solids
solids whose composite units are ions; they generally have high melting points. composed of altering + and - ions. not conductive. Brittle, Hard ex: NaCl, MgO
diffusion
spreading of a substance within a dispersing medium.
hydrogen bonding
strong type of intermolecular dipole-dipole attraction. Occurs between hydrogen and F, O or N. ex: in water molecule the hydrogen atoms have a large partial positive charge and the oxygen atoms has a large partial negative charge. when water approach, a hydrogen atom on one molecule is attracted to the lone pair of electrons on the oxygen atom on the other molecule.
Compared to intramolecular forces, the strength of intermolecular forces is
substantially less
A measure of the average kinetic energy of the particles in a sample of matter is called its _____________________
temperature
fluidity
the ability of a substance to flow easily. Gases and liquids are classified as fluids because they can flow and diffuse.
You are given a balloon filled with a known volume of helium gas. You place the balloon inside a freezer for an hour. What will the balloon look like after being in the freezer?
the balloon should look smaller than it did before going into the freezer
surface tension
the energy required to increase the surface area of a liquid by a given amount; results from an uneven distribution of attractive forces.
Cohesion
the force of attraction between identical molecules.
Adhesion
the force of attraction between molecules that are different.
critical point
the highest temp at which a pure material can exist in vapor/liquid equilibrium
Compressibility
the measure of how much a given volume of matter decreases when placed under pressure
capillary actions
the movement of a liquid such as water. It helps explain paper towels can absorb large amounts of water.
if the pressure and temperature of a gas remain constant, the volume will increase if
the number of moles of the gas increases
vapor pressure
the pressure exerted by a vapor over a liquid
Graham's Law of Dif/Effusion
the rate of effusion of gaseous substance is inversely proportional to square root of its molar mass.
A phase diagram is a graphic representation of
the relationship of the state of a substance to the temperature and pressure
the physical properties of gases, liquids, and solids are derived from
the strength of attractive forces.
Dalton's Law of partial pressure
the total pressure by a mixture of gases is equal to the sum of the partial pressures of the constituent gases.
molar volume
the volume occupied by 1 mole of a gas at standard temperature and 1.0 atm pressure (STP); 22.4 L
All three states of matter can exist in equilibrium at the triple point
true
all air is a mixture of several gases, it behaves like a single gas
true
the volume of a gas is equal to the volume of its container
true
The pressure exerted by a gas over a liquid is called _____________________
vapor pressure
A measure of the resistance of a liquid to flow is called
viscosity
boyle's law states that the pressure of a gas is inversely proportional to its
volume
Properties of crystalline solids
well-defined edges and faces, diffract x-rays, and tend to have sharp melting points.
properties of crystalline solids
well-defined edges and faces, diffract x-rays, and tend to have sharp melting points.
effusion
when a substance escapes through a tiny prehole or other hole
David has two containers of two different gases at the same temperature and pressure. David could assume all of the following EXCEPT -when the temperature is increased, the volume of both containers will increase -when the pressure is decreased, the temperature of both containers will increase -both containers contain the same number of gas particles -when the pressure is increased, the volume of both containers will decrease
when the pressure is decreased, the temperature of both containers will increase
