Chapter 11 gases and kinetic molecular theory

Question 1

properties

Answer 1

1. assumes both the shape and volume of its container
2. compressible
3. low densities
4. miscible in all proportions

Question 2

Kinetic molecular theory

Answer 2

the theory that models the behavior and properties of gases

1. the size of gas particles is negligibly small compare to the volume they occupy
2. gas particles are moving at random with no attractive forces between them
3. collisions between particles are completely elastic
4. the average kinetic energy of particles is proportional to the kelvin temperature

Question 3

average kinetic energy

Answer 3

KE=1/2mv^2

at a given temperature lower mass molecules move faster

Question 4

mean free path

Answer 4

though molecules are moving fast. the average distance that a molecule travels between collisions

Question 5

diffusion

Answer 5

the process by which molecules spreed out

molecules move from region of high concentration to a region of low concentration

Question 6

effusion

Answer 6

the process by which a gas escapes from a container through a tiny hole

grahams law

rateα√1/M

rate gas A÷rate gas B= √Mb/Ma

Question 7

Pressure

Answer 7

a force exerted per unit area

SI unit: Pascal, Pa

1Pa= 1n÷m^2

Question 8

atmospheric pressure

Answer 8

1 atm=101,325 Pa
=101.325 kPa
=14,7 lbs/in^2
760 mmHg=760torr

Question 9

Barometer

Answer 9

instrument used to measure the atmospheric pressure

P=hgd

h: height
g: gravitation acceleration, 9.834 m/s
d: density, kg/m^3

Question 10

manometer

Answer 10

instrument used to measure the pressure of a gas sample

Question 11

Boyle’s law

Answer 11

the volume of a fixed amount of gas at constant temperature in inversely proportional to its pressure

Vα1/p constant T and n
V-P= constant V1P1=V2P2

Question 12

charles law

Answer 12

the volume of a fixed amount of gas at constant pressure is directly proportional to its kelvin temperature

VαT constant P and n
V/T=constant

V1/T1=V2/T2

Question 13

avogadros law

Answer 13

the volume of a gas at fixed pressure and temperature is directly proportional to the number of moles of the gas
present

Vαn constant V and T
V/n=constant

V1/N1=V2/N2

Question 14

amontons law

Answer 14

the pressure of a fixed amount of gas at a fixed volume is directly proportional to its kelvin temperature

PαT=constant V and n
P/T=constant

P1/T1=P2/T2

Question 15

Standard temperature and pressure, STP

Answer 15

to compare gases we can fix parameters of T and P

STP=0ºC and 1 atm
PV=nRT

Question 16

density of gases

Answer 16

at STP the volume of 1 mole go gas is 22.41L

D=mass/volume

Question 17

general equation for densities of gases

Answer 17

d=PM/RT

moles can be converted into grams using molar mass

Question 18

deviations

Answer 18

any gas that obeys the ideal gas law equation is said to be an ideal gas

deception over under two condition:

1. High pressure
2. Low temperature

Question 19

high pressure KMT

Answer 19

the size of gas particles is negligible compared to the volume they occupy.

increase number of particles
reduce the volume

real gas:the volume of the particles are no longer negligible

idea gas: V=nRT/P VDW V=nRT/P +rb V=nb=nRT/P

the volume of the ideal gas is important. b: correction factor, L/mol

Question 20

low temperature KMT

Answer 20

gas particles are moving at random with no attractive forces between them

real gas: as molecules slow down attractive forces causes them to stick together

this causes a drop in collision which decreases the pressure

ideal gas P=nRT/V VDW P=nRt/V-a(h/v)^2 P+a(n/v)^2=nRT/P

the pressure decreases due to slower molecules
a: correction factor, L^2•atm/mol^2

Question 21

van der Waals equation

Answer 21

VDW[p+a(n/v)^2][v-nb]=nRT/P

Question 22

particle pressure, PgasA

Answer 22

the pressure due to any individual gas component in a gas

most gas samples are mixtures

Ptotal= ntotalRT/v = Pa+Pb+Pc

Question 23

dalton law

Answer 23

in a mixture of non-reacting gases the total pressure exerted is equal to the sum of the partial pressures of the individual gases

Pa=XaPtotal

X:mol fraction=mol component A/total moles