GAS Laws chapter 10 p303 KMT Kinetic Molecular Theory 1. Gases consist of particles far apart....

GAS Laws chapter 10 p303 KMT

Kinetic Molecular Theory1. Gases consist of particles far apart.

2. Collisions between particles are elastic.elastic meaning = no net loss of

KE

3. Gas particles are in constant, rapid, random motion

4. No forces of attraction or repulsion between gas particles.

5. Average KE of a gas depends on Temperature of gas.

Ideal Gases: an imaginary gas that

perfectly fits all assumptions of KMT.

(Noble gases) closest thing to it

Real Gases: does not behave completely

to the laws and theories of the KMT.

Need to know 4 items for understanding Gases

Volume: liters and milliliters

Temperature: Kelvin K K = 273 + oC convert 42oC =

126oC=212oC=

Zero degrees Kelvin = absolute zero

coldest temperature never reachable

Need to know 4 items for understanding Gases

Volume: Temperature:

# of moles or molecules

avagadro’s number 6.022 x 1023 molecules per mole

22.4 liters per mole@ STP

STP === standard temperature pressure(OoC or 273K( (1atm)

P. 310 Pressure: atm atmosphere of pressure

1 atm = 760 mm Hg = 760 torr = 101.3 kpaShow overhead 49

Sea level pressure = 1 atm or 760mm Hg or 101.3 kpa

STP === standard temperature pressure

(OoC or 273K) (1atm)

Average pressure in Denver Colorado is 0.083atm.

Express in mm Hg and kpa

Boyles Law: keeping temperature same

pressure up = volume down

pressure down = volume up

P1V1 = P2V2

When cap comes off …pressure goes down

= volume goes up.

Video under pressure

Charles Law: keeping pressure same

temperature up volume up temperature down volume down

Balloon in freezer vs balloon next to heatCar tires in winter vs. tires in summer

V1 = V2 T1 T2

Video wok/baloons

Gay-Lussac’s law : keeping volume same

Temperature up = pressure up

Temperature down = pressure down

Throw hair spray can in fire

P1 P2

T1 T2

video crushing cans

What happens to the tire as you add pressure?

Why are weather balloons under inflated?

P. 321 Combined Gas Laws: all 3 put together

P1V1 = P2V2

T1 T2Worksheet 10.33

1) If I initially have a gas at a pressure of 12 atm, a volume of 23 liters, and a temperature of 200k, and then I raise the pressure to 14 atm and increase the temperature to 300 K, what is the new volume of the gas?

3) A gas that has a volume of 28 liters, a temperature of 45c, and an unknown pressure has its volume increased to 34 liters, and its temperature decreased to 35c. If I measure the pressure after the change to be 2.0 atm, what was the original pressure of the gas?

Combined Gas Law

P1V1 = P2V2

T1 T2

Ideal Gas Law

Involves P,V,T & …number of moles of gas

PV = nRTAll units must be : P = atm

V = liters

T = Kelvin

n = #of moles

R = .0821 liters x atm

moles x K R is a constant …….. Like pi is a constant 3.14 ws.11.21

Ws. 11.21

1. If I have 4 moles of a gas at a pressure of 5.6 atm and a volume of 12 L, what is the temperature?

2. If I have an unknown quantity of gas at a pressure of 1.2 atm, a volume of 31 liters, and a temperature of 87c, How many moles of gas do I have?

3. If I contain 3 moles of gas in a container with a volume of 60 liters and at a temperature of 400K, what is the pressure inside the container?

Dalton’s Law of Partial Pressure

Total pressure of a mixture of gases =

sum of partial pressure of the component gases. Ptotal = P1 + P2 + P3 + P4 …

Overhead 48,50

Worksheet 10.38 problems 1,2,3

Diffusion & Effusion p. 351

KMT: 4- No significant forces of attraction or repulsion between gas particles

So…..gas particles can flow easily past one another

3- Gas particles are in constant, rapid, random

motion. They have KE.

So…..random motion of gas particles causes the gas particles to evenly mix.

Effusion = movement of a material through a tiny opening in a container.

“How fast a perfume comes out of a bottle”

Diffusion = movement of one material through another

material. Overhead 56

“Cooking cookies in the kitchen…others can smell it upstairs in the bedroom.”

Rate of Diffusion depends on mass of particles

---Skinny people can run faster than fat people---

---So can molecules---

Lighter molecule diffuse faster than heavy molecules @ STPoverhead 54

Of the following molecules which would diffuse faster?

l. Oxygen or Neon

2 Sulfur dioxide or carbon dioxide

3. Chlorine gas or krypton gas

Ch. 11 Gas Laws p. 333

Stoichiometry of gases

1 mole of oxygen has 6.022 x 1023 molecules

1 mole of hydrogen has 6.022 x 1023 molecules

1 mole of oxygen has a mass of 32 grams

1 mole of hydrogen has a mass of 2 grams(because diatomic)

Avagadro has a standard molar volume for gases

1 mole of any gas has a volume of 22.4 liters

Ws. 11.11

Ws.11.11

1. A chemical reaction produces 0.068 mol oxygen gas. What volume in liters is occupied by this gas at STP?

2. A sample hydrogen gas occupies 14.1 L at STP. How many moles of the gas are present?

3. At STP a sample of neon gas occupies 550 cm3. How many moles of neon gas does this represent?

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