Chemistry- Gas, Liquids, Solids

Question 1

Ideal Gas

Answer 1

• hypothetical, stays in gas phase in all conditions
• behaves accordingly to KMT
• low molar mass
• non existent attractive forces
• negligible volume (no/ very small volume)

Question 2

Real Gases

Answer 2

• does not behave according to KMT
• high molar mass
• attractive forces present
• have volume

Question 3

Real Gases behave most ideally under

Answer 3

high temperatures and low pressure

Question 4

properties of gas

Answer 4

• have mass
• no definite shape/volume (expand to fill container)
• are fluids
• low density and high comprehensibility
• diffuse (mix) very easily
• exerts pressure on its surroundings
• pressure of gas depends on its temperature

Question 5

Properties of Liquids

Answer 5

• largely dependent upon intermolecular forces (solids- highest van der waals forces)
• relatively high density
• can’t be compressed, have definite volume
• diffuse easily
• exhibit surface tension and capillary action

Question 6

surface tension

Answer 6

a force that tends to pull adjacent parts of a liquid’s surface together, decreasing surface area to the smallest possible size

Question 7

capillary action

Answer 7

spontaneous rising of a liquid in a narrow tube

Question 8

cohesive forces

Answer 8

intermolecular forces among the molecules of the liquid

Question 9

adhesive forces

Answer 9

• forces between the liquid molecules and the container

- water has more adhesive forces

Question 10

viscosity

Answer 10

• measure of a liquid’s resistance to flow

- liquids with larges intermolecular forces or molecular complexity tend to be highly viscosous

Question 11

properties of solids

Answer 11

• definite shape and volume
• high density
• incompressible
• low rate of diffusion
• exists as crystal lattices (definite melting point)

Question 12

crystalline

Answer 12

• well organized
• definite melting point
• ex. SiO2 (quartz), diamond, salt, sugar, graphite

Question 13

Amorphous

Answer 13

• no organization
• range of melting point
• plastic, SiO2 (glass), silicon

Question 14

ionic solids

Answer 14

• large networks of cations and anions
• highly organized
• high melting point
• conducts electricity as liquids and when aqueous (ions must be free)
• generally soluble in water
• form electrolytic solutions when dissolved in water
• ex. ammonium carbonate

Question 15

molecular solids

Answer 15

• covalently bonded molecules held together by intermolecular forces
• low melting point (25 C to 300 C)
• do not conduct electricity (no charge)
• ex. ice, glucose, iodine, sulfur (S8)

Question 16

network covalent solids

Answer 16

• large network of covalently conded atoms
• highly organized
• high melting point (300 C)
• generally not conductive of electricity (exception: graphite)

Question 17

metallic solids

Answer 17

• sea of shared, mobile electrons
• conducts electricity
• high melting point (1500 C)
• alloys, elements

Question 18

exothermic

Answer 18

• releases heat/energy
• causes molecules to move slowly
• gas to liquid to solid

Question 19

endothermic

Answer 19

• requires heat/energy
• causes molecules to move quickly
• solid to liquid to gas

Question 20

dynamic equilibrium

Answer 20

• phase changes are always at equilibrium

- ex. S L rate of melting = rate of freezing

Question 21

vapor pressure

Answer 21

• pressure exerted by a vapor in equilibrium with the liquid phase at a given temperature
• high temp, high vapor pressure

Question 22

volatile

Answer 22

high vapor pressure (low boiling point)

Question 23

nonvolatile

Answer 23

low vapor pressure

Question 24

boiling point

Answer 24

• the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure
• water doesn’t always have to boil at 100 C

Question 25

heat of vaporization

Answer 25

- heat required to turn liquid to gas | - higher than heat of fusion because it takes a lot of energy to break intermolecular forces in liquids completely

Question 26

heat of fusion

Answer 26

heat required to turn solid to liquid

Question 27

temperature in phase changes

Answer 27

there is no temperature change until the phase is complete

Question 28

potential and kinetic energy in phase changes

Answer 28

- as temperature changes, kinetic energy increases | - during phase changes (when temp. stays the same), potential energy icreases

Question 29

triple point

Answer 29

all phases of mater exists simultaneously

Question 30

critical point

Answer 30

substance can't exist as a liquid

Question 31

pressure

Answer 31

- the force per unit on a surface - pressure = force/ area (newton/square meter) = 1 Pa - 1 standard atmosphere = 101, 325 Pa (pascal) - 1 atm = 760 mm Hg = 760 torr = 14.7 psi = 101.3 kPa

Question 32

barometer

Answer 32

device used to measure atmospheric pressure

Question 33

manometer

Answer 33

- device used for measuring the pressure of a gas in a container - Pgas = Patm - h when Patm is less than atmospheric pressure - Pgas = Patm + h - h is the difference b/w two mercury levels

Question 34

temperature

Answer 34

- average kinetic energy of a sample - Tk = 273 + Tc - *always work in kelvin*

Question 35

Boyle's law

Answer 35

- at a constant temperature, pressure and volume of a gas are inversely related (high pressure, low volume) - k = PV where k is a constant for a given sample of air at a specific temperature - P1V1 = P2V2

Question 36

Charles's Law

Answer 36

- at a constant pressure, volume and temperature (in K) of a gas are directly related (high volume, high temperature) - V1/T1 = V2/T2 - V = bT (b is a proportionality constant), b= T/V - 0K is called absolute zero

Question 37

Gay-Lussac's Law

Answer 37

- states that at a constant volume, the pressure of a gas is directly proportional to its temperature in Kelvin - P1/T1 = P2/T2

Question 38

Combined Gas Law

Answer 38

- P1V1/T1 = P2V2/T2 | - P1V1T2 = P2V2T1

Question 39

Avogadro's Law

Answer 39

- volume and number of moles are directly related (constant temp. and pressure) - v = an (a is a proportionality constant) - V1/N1 = V2/N2

Question 40

ideal gas law

Answer 40

- relates pressure, volume, temperature, and quantity in a single equation - PV = nRT *P MUST BE IN ATM* - R = 0.0821 atm-L/mol-K

Question 41

Dalton's Law of Partial Pressure

Answer 41

- for a mixture of gases in a container, - Ptotal = P1 + P2 + P3 + ... - the total pressure exerted is the sum of the pressures that each gas would exert if it were alone

Question 42

diffusion

Answer 42

movement of high concentration to low concentration

Question 43

effusion

Answer 43

diffusion through a tiny aperture

Question 44

rate of effusion

Answer 44

- measures the speed at which the gas is transferred into the chamber

Question 45

Graham's Law of Effusion

Answer 45

- rate of effusion of a gas is inversely proportional to the square root of the molar mass of the gas - rate of effusion for gas 1/ rate for gas 2 = sqrt m2/m1 or sqrt density2/density1 - m1 and m2 are molar masses of gas - put heavier gas in bottom (ex. rate H2/ rate O2) - lighter gases travel faster

Question 46

molar mass of gas

Answer 46

dRT / P (g/ mol)

Question 47

real gases

Answer 47

- we must correct for non-ideal gas behavior when pressure of gas is high and temp is low - under conditions, concentration is high and attractive forces become important

Question 48

Kinetic Molecular Theory

Answer 48

- gases consist of many tiny particles that are very far apart - collisions b/w gas particles and container walls are perfectly elastic - gas particles are in continuous, rapid, random motion- they have kinetic energy - there are no forces of attraction - temp. depends on average kinetic energy of particles (higher temp, higher speed)