Week 3 Gases

Question 1

Kinetic Molecular Theory

Answer 1

Gases are made up of particles in constant random motion
Collisions result in a change in direction of motion

Question 2

3 Assumptions of the particulate model

1

Answer 2

1. Gases are negligibly small (particle size)
2. Average kinetic energy is proportional to temperature in K KEavg=3/2RT (Average kinetic energy DOES NOT depend on chemical identity)
3. Elastic collisions with each other and vessel (no loss of KE)

Question 3

Pressure equation

Answer 3

P=F/A (force/area)
P=dgh (densityxgravitational constantx height of fluid)

Question 4

What happens to a bag of potato chips at the top of a mountain

Answer 4

Bag expands because there is fewer atmospheric air particles colliding with the chip bag

Question 5

Manometer
What does each part of the equation mean (what are the constant numbers)

Answer 5

𝝙P (in Pa)=dgh
𝝙P= positive differential in pressure on both sides
density of manomter fluid dhg=12.384 g/ml
g=gravitational constant (9.8 m/s2)
h=difference in height of fluid in mm

Question 6

Explains what happens to pressure if the height of gas is lower higher?

Answer 6

• hgas< hatm
  Pgas>Patm
  Pgas (in PA)=Patm+dgh
  Pgas (in mmhg)=Patm+h
• hgas>hatm
  Pgas<Patm
  Pgas (in PA)=Patm-dgh
  Pgas (in mmhg)=Patm-h

Question 7

What are the ways to describe gases (physcial properties)

Answer 7

Pressure- how forceful are collisions with the vessel
Volume- how much space does the gas take up
Temperature- how fast are the particles on AVG
Moles- how many particles

Question 8

Avogadro’s
What are constants, what is the equation, is graph linear

Answer 8

T,P
V1/n1=V2/n2
YES

Question 9

Boyles
What is constant, what is the equation

Answer 9

n,T
P1V1=P2V2
Graph is NOT linear

Question 10

Charles
What is constant, what is the equation, is the graph linear

Answer 10

n,P constant
V1/T1=V2/T2

Question 11

What makes gases ideal

Answer 11

No attractive forces
Molecules have complete freedom to spread out and take up all the space in the vessel
Particles are negligibly small (particles volume not accounted for)

Question 12

Molar Volume and equation deriviation

Answer 12

Vm=RT/P
Volume that 1 mol of gas takes up

Question 13

What are STP conditions, what does 1 mol of gas occupy?

T

Answer 13

Temp: 273 K
P: 1 atm
Amount: 1 mol
1 mol=22.4 Liters

Question 14

Density Ideal gas law deriviation

Answer 14

d=PM/RT
M is molar mass