Chemistry (Gas laws)

Question 1

Pressure

Answer 1

Measured using barometer

Mercury Barometer

• vacuum (empty space) sucks in mercury.
• atmosphere pushing mercury avoiding spillage.
• equalizes with force of gravity.

Question 2

Ideal gas law

Answer 2

PV=nRT
n= # of miles
R= gas constant (8.314)

• T is same as container/surroundings.
• P in a flexible container= external pressure.
• P in rigid container= internal pressure.
• V in flexible container is variable.
• V in rigid container is fixed.

Question 3

For ideal gas equation to work

Answer 3

1. Gas molecules really small compared to space between them.
2. No inter molecular forces: no attraction or repulsion instead gas molecules bounce off each other.
3. Temp. Proportional to avg. Kinetic Energy
   a. High temperature: 273 Kelvins
   b. Follow pressure: 1atm (STP)

Question 4

Boyle, Charles and Avogadros Law

Answer 4

Boyle: P and V inversely proportional (P•V)
Charles: V and T proportional (V/T)
Avogadros: n and V are proportional (V/n)

Question 5

Molar volume

Answer 5

22.4 L/mol => STP

Question 6

Combined gas law

Answer 6

P1V1/T1=P2V2/T2

Question 7

Deviations from ideal gas

Answer 7

Pideal > Preal
Videal < Vreal

Real gases have IMFs
- P + n^2•a/v^2

Real gases occupy volume
(v-n•b(mole mass))

Question 8

Daltons Law of partial pressure

Answer 8

Only applies to a mixture of gases

Ptotal= (Ptotal)•(X= mole fraction)•gas 1+ (Ptotal)•(X= mole fraction)•gas 2

Question 9

Kinetic moleculear theory

Answer 9

Assumptions:

• molecules occupy no volume.
• no IMFs
• random motion
• elastic collisions
• Avg. Kinetic energy proportional to absolute temperature.
  a. KE=3/2•k•T

Average molecule speed:
Vrms= √3•R•T/M

Question 10

Diffusion vs Effusion

Answer 10

r1/r2= √m2/m1
r=rate
m= molecular weight