The Gas Phase .

Question 1

Gas is..?

Answer 1

least dense phase of matter
are fluids and therefore conform to the shapes of their containers
are easily compressible
described by T, P, V, and n

Question 2

1 atm =

Answer 2

760 mmHg = 760 Torr= 101.325 Pka

Question 3

What is a simple mercury barometer?

Answer 3

measures incident (usually atmospheric) pressure. As pressure increases, more mercury is forced into the column, increasing its height. As pressure decreases, mercury flows out of the column under its own weight, decreasing its height.

Question 4

What is STP (standard temp and pressure)?

Answer 4

273 K (0 C) and 1 atm

Question 5

Equations for gas assume..?

Answer 5

negligible mass and volume of gas molecules

Question 6

1 mole of an ideal gas occupies how much volume at STP?

Answer 6

22.4 L

Question 7

What is the ideal gas law?

Answer 7

it describes the relationship between the four variables of the gas state for an ideal gas.
PV=nRT . R = 8.314

Question 8

What is Boyle’s principle?

Answer 8

is a special case of the ideal gas law for which the pressure and temp are held constant; it shows an inverse relationship between volume and pressure.

Question 9

What is Charle’s law?

Answer 9

is a special case of the ideal gas law for which temperature and the number of moles are held constant; it shows a direct relationship between temp and volume

Question 10

What is Gay-Lussac’s law?

Answer 10

is special case of the ideal gas law for which volume and number of moles are held constant; it shows a direct relationship between temp and pressure.

Question 11

What is the combined gas law?

Answer 11

is a combination of Boyle’s, Charle’s, and Gay-Lussac’s laws; it shows an inverse relationship between pressure and volume along with direct relationships between pressure and volume with temperature.

Question 12

What is Avagadro’s principle?

Answer 12

it is a special case of the ideal gas law for which the pressure and temperature are held constant; it shows a direct relationship between the number of moles of gas and volume

Question 13

What is Dalton’s law of partial pressure?

Answer 13

states that individual gas components of a mixture of gases will exert individual pressure in proportion to their mole fractions. The total pressure of a mixture of gases is equal to the sum of partial pressures of the component gases.

Question 14

What is Henry’s Law?

Answer 14

states that the amount of gas dissolved in solution is directly proportional to the partial pressure of that gas at the surface of solution.

Question 15

What is the kinetic molecular theory?

Answer 15

attempts to explain the behavior of gas particles. It makes a number of assumptions about the gas particles:

• gas particles have negligible volume
• they do not have intermolecular attractions or repulsions
• particles undergo random collision with each other and wall of container
• collisions are elastic
• the average kinetic energy of the gas particles is directly proportional to the temp

Question 16

What is Graham’s law?

Answer 16

describes the behavior of gas diffusion or effusion, stating gases with lower molar masses diffuse or effuse faster than gases with higher molar masses at the same temperature.

Question 17

What is diffusion?

Answer 17

the spreading out of particles from high to low concentrations.

Question 18

What is effusion?

Answer 18

is the movement of gas from one compartment to another through a small opening under pressure.

Question 19

What are real gases?

Answer 19

they deviate from ideal behavior under high pressure (low volume) and low temp conditions:
-high P, low V, or low T will occupy less V than predicted by the ideal gas law because the particle have intermolecular attractions
at high P, low V, or low T, real gases occupy more volume than predicted because particle occupy physical space

Question 20

What is the van der Waals equation of state?

Answer 20

used to correct the ideal gas law for intermolecular attractions and molecular volume.
(P+n^2a/V^2)(V-nb) = nRT

Question 21

Density of gas

Answer 21

p = m/V = PM/RT

Question 22

combined gas law

Answer 22

P1V1/T1 = P2V2/T2 .

Question 23

avagadro’s principle

Answer 23

n/V = k or n1/V1 =n2/V2

Question 24

boyle’s law

Answer 24

PV= k or P1V1=P2V2

Question 25

charle’s law

Answer 25

V/T= K or V1/T1 = V2/T2

Question 26

guy-Lussac’s law

Answer 26

P/T = k or P1/T1 = P2/T2

Question 27

dalton’s law for total pressure from partial pressure

Answer 27

PT= Pa+Pb+Pc

Question 28

Dalton’s for partial pressure from total pressure

Answer 28

PA=XAPT

Question 29

Henry’s law

Answer 29

[A] =kH x PA or [A]1/P1=[A]2/P2 = kH

Question 30

average kinetic energy of a gas

Answer 30

KE = 1/2 mv^2 = 3/2 kB T . average kinetic energy of a gas particle is proportional to the absolute temperature of the gas.

Question 31

root-mean-squared speed

Answer 31

u rms = sqrt(3RT/M)

Question 32

Graham’s law

Answer 32

r1/r2 = sqrt(M2/M1)

Question 33

Van der Waals equation of state

Answer 33

(P+ n^2/ V^2)(V-NB) = nRT

Question 34

What is vapor pressure?

Answer 34

it is the pressure exerted by evaporated particles above surface of a liquid. It forces some of the gas back into the liquid phase, and equilibrium is reached between evaporation and condensation. Expressed by henry’s law

Question 35

What is the Boltzman constant

Answer 35

1.38 x 10^-23 J/K. Serve as a bridge between macroscopic and microscopic behaviors of gases. Represents kB

Question 36

Maxwell-Boltzman distribution curve shows what?

Answer 36

The distribution of gas particle speeds at a given temperature.