Gas Laws.notebook

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May 05, 2014

Gas Laws

.P V = kP1V1 = P2V2

• At constant temperature, all gases behave the same when compressed• As increasing pressure is applied to a gas in a closed container,

the volume of the gas decreases• The product of pressure and volume is always constant

Why doesthe plungerbounce back?

Use the terms:­particles­collisions­Walls ofcontainer­plunger

The gas in a balloon has a volume of 7.5 L at 100 kPa. The balloon is released into the atmosphere, and the gas in it expands to a volume of 11 L. Assuming a constant temperature, what is the pressure on the balloon at the new volume?

• List what you know• Write the formula• Solve for the variable you need• Plug 'n chug

70 kPa

P1V1 = P2V2

= 70 kPa

1 atm = 101.325 kpa= Standard Pressure

(at sea level)

• Jacques Charles discovered that the volume of a gas is directly proportional to its temperature (Kelvin scale)• At constant pressure, the volume of a gas divided by its absolute temperature is constant.

V1 V2

T1= T2

VT = k V

Tk =

Graph

_T,_KE,_V, _Collisions, _Pressure

Why does theplunger go up asthe temperatureincreases?

Gas Laws.notebook

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May 05, 2014

A sample of gas occupies 24 m3 at 175.0 K. What volume would the gas occupy at 400.0 K?55m3

Answer

• List what you know• Write the formula• Solve for the variable you need• Plug 'n chug

waterfreezes

oFoCK

Write a formula that will convert oC to K

K oC=?? ??oC + 273 = KAnswer

Do p.440#1­2

Do p. 436#1­4. Show workDo p.440#1­2

1260mL

1. A syringe has a sample of gas with a volume of 3.95 mLat a pressure of 1.00 atm. What is the pressure of the gas in the syringe if the volume is changed to 2.53 mL?

1.56 atm

2. A partially inflated weather balloon has a volume of 1.50 x 103 L at 98.8 kPa of pressure. What is the volume of the balloon when it is released to a height where the pressure is 44.1 kPa?

3.36 x 103 L

3. A sample of gas has a volume of 852 mL at 198 K. What volume does the gas occupy at 293 K?

4. A sample of gas has a volume of 234.9 L at a temperature of 23oC. What temperature is necessary to have a volume of 200.0 L? 252 K or ­21oC

= 3,360 L

1. A syringe has a sample of gas with a volume of 3.95 mLat a pressure of 1.00 atm. What is the pressure of the gas in the syringe if the volume is changed to 2.53 mL?• List what you know• Write the formula• Solve for the variable you need• Plug 'n chug

2. A partially inflated weather balloon has a volume of 1.50 x 103 L at 98.8 kPa of pressure. What is the volume of the balloon when it is released to a height where the pressure is 44.1 kPa?

3. A sample of gas has a volume of 852 mL at 198 K. What volume does the gas occupy at 293 K?

A sample of gas has a volume of 234.9 L at a temperature of 23oC. What temperature is necessary to have a volume of 200.0 L?

252 K or ­21oCoC + 273 = K

Gas Laws.notebook

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May 05, 2014

Peter

Tom

• Gay­Lussac discovered that the pressure of a gas is directly proportional to its temperature (Kelvin scale)• At constant volume, the pressure of a gas divided by its absolute temperature is constant.

P1 P2

T1= T2

PT = k

TP VP

Tk =

Uncle Larry tells his nephews to never throw paint cans into the fire. "Why?" they ask. "I'll show you." Uncle Larry builds a bonfire. "Get ready to run," he warns.The can is rated to 9.00 atm before bursting. The temperature inside the can reaches 414oC after being in the fire for 17 sec. The temperature before being thrown recklessly was 72 oC., with a pressure of 7.00 atm. Will it burst? Show work.

H/W: p. 449 # I­4

Uncle Larry tells his nephews to never throw paint cans into the fire. "Why?" they ask. "I'll show you." Uncle Larry builds a bonfire. "Get ready to run," he warns.The can is rated to 9.00 atm before bursting. The temperature inside the can reaches 414oC after being in the fire for 17 sec. The temperature before being thrown recklessly was 72 oC., with a pressure of 7.00 atm. Will it burst? Show work.

p. 449 # I­4

P1V1 P2V2

T1= T2

P VT

Boyle's Law + Charles' Law + Gay­Lussac's Law = Combined Gas Law

H/W: p. 449 # 1­4

Gas Laws.notebook

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May 05, 2014

A weather balloon containing helium with a volume of 410.0 L rises in the atmosphere and is cooled from 27oC to ­27oC. The pressure on the gas is reduced from 110.0 kPa to 25.0 kPa. What is the volume of the gas at the lower temperature and pressure?

H/W:p.436#1­4p.440#1p.449#1­4

A weather balloon containing helium with a volume of 350.0 L rises in the atmosphere and is cooled from 24oC to ­31oC, and increases in size to 989 L. The pressure on the gas changes from 115.0 kPa to what new pressure?

P

1 atm = 101,325 Pa = 101.325 kPa1 atm = 760 mm HgSTP = STANDARD TEMPERATURE

AND PRESSURE

273K

1 atm = 101,325 Pa = 101.325 kPa1 atm = 760 mm Hg

STP = STANDARD TEMPERATUREAND PRESSURE

Gas Laws.notebook

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May 05, 20141. A gas has a volume of 18.5 L at 85.5 kPa and 296 K. What is the volume of the gas at STP?

2. A balloon full of helium gas has a volume of 132 L at 99.7 kPa and 30oC. What temperature is required for the balloon to have a volume of 176 L at a pressure of 77.6 kPa?

3. A plastic bag is inflated to a volume of 3.89 L at 1.095 atm and 23oC. If the volume drops to 3.05 L at a temperature of ­4oC, what is the new pressure?

STP = STANDARD TEMPERATUREAND PRESSURE

273K

1 atm = 101,325 Pa = 101.325 kPa1 atm = 760 mm Hg

1. A gas has a volume of 18.5 L at 85.5 kPa and 296 K. What is the volume of the gas at STP?2. A balloon full of helium gas has a volume of 132 L at 99.7 kPa and 30oC. What temperature is required for the balloon to have a volume of 176 L at a pressure of 77.6 kPa?

3. A plastic bag is inflated to a volume of 3.89 L at 1.095 atm and 23oC. If the volume drops to 3.05 L at a temperature of ­4oC. What is the new pressure?

p.449#4A sample of carbon dioxide gas occupies 45m3 at 750 K and 500. kPa. What is the volume of this gas at STP?

V

Gas Laws.notebook

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May 05, 2014

Does he look like a pvnrt?

To solve for P, V, T, or the number of moles:

Where:n = number of molesR = (8.314 L x kPa) / (mol x K)R = (0.0821 L x atm) / (mol x K)1 atm = 101.325 kPa

P V= n R T

A sample of carbon dioxide with a mass of 0.250 g is placed in a 350.0 ml container at 400.0 K. What is the pressure exerted by the gas?

Where:n = number of molesR = (8.314 L x kPa) / (mol x K)R = (0.0821 L x atm) / (mol x K)1 atm = 101.325 kPa

H/W

­Intro Gas Laws w/s

p.436 pp#1­4; p.440#1­2; 449#1­4

p.451#5­9

p.462 #27,29,30,44,46

Wed.

Thurs.

Tues.

1) How many moles of a gas are in a balloon that has a volume of 15.9 L at a pressure of 149 kPa and a temperature of 28oC?

4/10/14

2) What mass of ammonia, NH3, is required to fill a 14.88 L bottle to a pressure of 199 kPa at 25oC?

Where:n = number of molesR = (8.314 L x kPa) / (mol x K)R = (0.0821 L x atm) / (mol x K)1 atm = 101.325 kPa

4/22/13

27) A flexible container with 2.0 L of methyl bromide hasan internal pressure of 506.6 kPa at 25oC. What is thevolume of methyl bromide at standard pressure if thetemperature remains constant?

29) A child receives a balloon filled with 2.30 L of helium from a vendor at an amusement park, where the temperature is 311 K. What will the volume of the balloon be when the child brings the balloon home to an air­conditioned house at 295K?

Gas Laws.notebook

7

May 05, 2014Hydrogen peroxide (H2O2) decomposes to water and oxygen (O2) gas.• Write the balanced equation for the reaction.• After hydrogen peroxide reacts with a catalyst, 36.7 mL of oxygen gas are collected in a room at 22° C and 1.01 atm. Calculate the number of moles of gas that were produced.• Calculate the mass of the hydrogen peroxide that must have reacted.

4/11/14

H2O2(l) H2O(l) + O2(g)Hydrogen peroxide (H2O2) decomposes to water and oxygen (O2) gas.• Write the balanced equation for the reaction.• After hydrogen peroxide reacts with a catalyst, 36.7 mL of oxygen gas are collected in a room at 22° C and 1.01 atm. Calculate the number of moles of gas that were produced.• Calculate the mass of the hydrogen peroxide that must have reacted.

4/11/14

H2O2(l) H2O(l) + O2(g)

A 283.3­g sample of X2(g) has a volume of 30 L at 3.2 atm and 27 °C. What is element X?

PV = nRT

= moles X2

283.3g X2 = ? mol X2

PVRT = n =

X = ? g = ? mol X

Check the periodic table...

29) A child receives a balloon filled with 2.30 L of helium from a vendor at an amusement park, where the temperature is 311 K. What will the volume of the balloon be when the child brings the balloon home to an air­conditioned house at 295K?

What mass of ammonia, NH3, is required to fill a 14.88 L bottle to a pressure of 199 kPa at 25oC?

H/W ­Intro Gas Laws w/s­p.451 #5­9

A) A sample of gas has a volume of 852 mL at 189 K. What volume does the gas occupy at 293 K?

B) How many moles of gas are in a balloon that has a volume of 15.9L at a pressure of 149kPa and a temperature of 28 C?

V2 = 1320 mL or 1.32 L

T2 = 252 K, or ­21 Cn = 0.947 mol

H/W ­ p.462 #27,29,30,44,46

B) A sample of gas has a volume of 234.9L at a temperature of 23 C. What temperature is necessary to have a volume of 200.0L?

CA Science Standards: Chemistry3. e. Students know how to calculate the masses of reactants and products in a chemical reaction from the mass of one of the reactants or products andthe relevant atomic masses.

4. The kinetic molecular theory describes the motion of atoms and molecules and explains the properties of gases. As a basis for understanding this concept: a. Students know the random motion of molecules and their collisions with a surface create the observable pressure on that surface.

4. c. Students know how to apply the gas laws to relations between the pressure, temperature, and volume of any amount of an ideal gas or any mixture of ideal gases.

Gas Laws.notebook

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May 05, 2014

4/22/14

How many liters of hydrogen gas can be producedat 300.0 K and 104 kPa pressure if 20.0g sodiummetal is reacted with water according to the following equation?

Na(s) + H2O(l) ­­> NaOH(aq) + H2(g)hints:• balance equation• choose which gas law to use• solve for volume• convert g to moles• moles Na moles H2 • plug 'n chug

4/22/14

How many liters of hydrogen gas can be producedat 300.0 K and 104 kPa pressure if 20.0g sodiummetal is reacted with water according to the following equation?

Na(s) + H2O(l) ­­> NaOH(aq) + H2(g)hints:• balance equation• choose gas law to use• solve for volume• convert g to moles• moles Na moles H2 • plug 'n chug

(not NOaH)

(1 atm = 760 mm Hg = 101.325 kPa)

1) Calculate the value of the ideal gas constant, R, if exactly one mole of an ideal gas occupies a volume of 22.414 liters at 0.00˚C and 755 mm Hg atmosphere pressure. Give R in L kPa/mol K.

2) Calculate Percent Error:

4/23/14

(1 atm = 760 mm Hg = 101.325 kPa)

1) Calculate the value of the ideal gas constant, R, if exactly one mole of an ideal gas occupies a volume of 22.414 liters at 0.00˚C and 755 mm Hg atmosphere pressure. Give R in L kPa/mol K.

2) Calculate Percent Error:

Algebra: R =

Plug 'n Chug: R =

Answer: R =

Calculate the mass of carbon dioxide that would be needed to fill a 2.00 L bottle at 22.00 C and 757 mm Hg. 4/24/14

(1 atm = 760 mm Hg = 101.325 kPa)

1) Calculate the mass of carbon dioxide that would be needed to fill a 2.00 L bottle at 22.00 C and 757 mm Hg. 4/24/14

(1 atm = 760 mm Hg = 101.325 kPa)

Gas Laws.notebook

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May 05, 2014

Dalton's Law of Partial Pressures

The total pressure of a mixture of gases is equal to the sumof the partial pressures of the individual gases:

Ptotal = PA + PB + PC

Each gas behaves as if the other gases are absent

= PA

= PB

= PC

Disappearing Toys: DRY ICE

Try:(1) Not getting frostbite!(2) Air hockey on your desk(3) Coin torture(4) Bubbling witch's brew(5) Misdemeanor (let Rongley do it instead!)

"Sublimation"CO2(s) CO2(g)

T, _ P

Dry ice:­78.50C (­109.30F)

Ice:00C

Liquid Nitrogen:−196°C (−321°F or 77 K)

Start: p.451#5­9

5) 1,100 kPa 6) 0.39 L N27) n=0.122 mol N2 D = ?

8) 5.3 x 10­3 mol SO2

9) 1 psi = 6.89286 kPaV2 = 275.7 L He# ballons = ?

2. A 283.3­g sample of X2(g) has a volume of 30 L at 3.2 atm and 27 °C. What is element X?

Step 1: Convert °C to KelvinT = °C + 273T = 27 + 273T = 300. K

Step 3: Find mass of 1 mol of X24 mol X2 = 283.3 g1 mol X2 = 70.8 g

Step 4: Find mass of 1 mol of X1 mol X2 = 70.8 g1 mol X = 35.4 gStep 5: Identify the element with molecular mass 35.4 gChlorine has a molecular mass of 35.4 gAnswer: Element X is Chlorine

Step 2: Solve Gas Law equation for nn = PV RT

n = (3.2 atm)(30 L)(0.08 atm L/mol K)(300 K)