Properties of all gases

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Properties of all gases

• Chapter 14
• with Ch 13 review.
• WOD are underlined.

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Properties of all gases

• When working with gases, there are 4 properties
  that must be considered
• Gas Properties Mass, Volume, Pressure,
  Temperature
• There are multiple equations The properties
  that change determine the equation to select to
  solve for the unknown.
• All the remaining properties must be held
  constant.

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From Chapter 13Phases

• Two of the properties determine the phase of an
  element
• Pressure
• Temperature

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From Chapter 13Phases

• What happens when you increase pressure (a lot)
  on gas?
• (What is one exception?)
• What happens when you increase temperature (a
  lot) on a solid?

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There is a pan of ice on the stove. What does
this Temperature graph look like?
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WRONG!
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Properties of all gases

• KNOW ALL THE FOLLOWING
• Pressure at STP is
• 1 atm 760 mm Hg 101.3 kPa 14.7 lbs/in2
• Volume
• 1 mL 0.001L 1cm3
• Temperature at STP is 273 K (0 Celsius)
• Use Kelvin (not Celsius)

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Standard Temperature and Pressure

• STP, Temperature and Pressure at Sea Level on a
  freezing day 101.3 kPa, 273 K
• KNOW ALL THE FOLLOWING
• Pressure at STP is
• 1 atm 760 mm Hg 101.3 kPa 14.7 lbs/in2
• Volume
• 1 mL 0.001L 1cm3
• Temperature at STP is 273 K (0 Celsius)
• Use Kelvin (not Celsius)

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Properties of all gases

• Pressure
• 1 atm 760 mm Hg 101.3 kPa 14.7 lbs/in2
• Discuss Gage pressure in a factory (diff from
  atm. Vs gage pressure in a lab (Boyles Law)

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Boyles Law what happens to pressure?
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Boyles Law P1V1 P2V2 (mass and temperature
constant) Volume of a gas varies inversely with
pressure V?P? or P?V?P1V1 P2V2 Or PV
Constant
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Steps to Solve Problems1. Known Find the
knowns.2. Unknown Find the unknowns.3.
Equation Pick the equation that matches the
knowns and unknowns.4. Units Make sure units
are the same on both sides. T in Kelvin.5.
SigFig Change the answer to the correct number
of significant figures.
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A 220mL balloon of air is at a pressure of
506.5kPa. What will be the volume of the balloon
at sea level (STP)?
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A 455mL balloon is taken from sea level up to a
point where the pressure is unknown. The balloon
has a new volume of 1.25L. What is the pressure?
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Review the last 2 slides. As height goes
upWhat happens to pressure?What happens to
volume?
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NaHCO3 HC2H3O2 ? H2O NaC2H3O2
CO2At STP, 2.5g of NaHCO3 produced 560 mL of
CO2 gas. What would the volume of this gas be on
top of mountain where the pressure is only 250 mm
Hg?Extra credit What is the percent yield of
CO2 produced? (Use Mass ratios)
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NaHCO3 HC2H3O2 ? H2O NaC2H3O2 CO2At
STP, 2.5g of NaHCO3 yields 560 mL of CO2 P2
250 mm Hg?Extra credit What is the percent
yield of CO2 produced?
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Charless Law What happens to a gas if it is
heated?
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Charless Law V1/T1V2/T2 (mass and
pressure constant) Volume of a gas varies
directly with its Kelvin temperature T? V? or
T?V?V1/T1V2/T2 or V/T Constant
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A balloon is filled with 5.00L of air with a
temperature of 00C. The balloon is placed by a
furnace and expands to 7.00L. What is the
temperature next to the furnace? Hint Use 273K
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Gay-Lussacs Law P1/T1P2/T2(mass and volume
constant) pressure of a gas varies directly with
its Kelvin temperature P? T? or
P?T?P1/T1P2/T2or P/TConstant
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Combined Gas Law(Temp is in Kelvin)
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The volume of a Get Well Soon balloon is 2.5L
at STP conditions. What would the volume of the
balloon be on the moon (-930C, 1.1x10-8kPa)
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Quiz 14.2A can of compressed air ruptures at an
internal pressure of 225 lbs/in2. At standard
temperature (0.00oC) the pressure is 55.5
lbs/in2. At what temperature will the can burst
(reach it bursting pressure)?
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Ideal Gas LawPVnRTPrairie Village is not a
Real Town R 8.31 ( LkPa)/(K mol) P, V, Tn
molesR 8.31 ( LkPa)/(K mol)
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How many grams of He are needed to fill a weather
balloon that is 2520L at sea level and 5.75oC?
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What is the pressure on the inside of a CO2
cartridge?(There are 12.1 grams, the temperature
in the room is 68.7F, and the volume is
15.9mL.)Would the pressure change if the room
temperature changed?
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PVnRTX (0.0159L) 0.275mol (8.31 L .kPa/mol.K)
293.4K42,200 kPa or 42,169.33019 kPaabout
417atm
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Sample Problem
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NaHCO3 HC2H3O2 ? H2O NaC2H3O2 CO2
A classroom has a temperature of 303K and a
pressure of 105kPa. What volume of CO2 will be
produced from 12.5g of NaHCO3?
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Quiz 14.3 How many moles of H2 are needed to
fill a balloon that is 2.50L, at sea level, and
295.75K?Extra credit H2O Na ? NaOH
H2How many grams of Na will it take to fill the
balloon?
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Review
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Properties of all gases

• When working with gases, there are 4 properties
  that must be considered
• Gas Properties Mass, Volume, Pressure,
  Temperature
• There are multiple equations The properties
  that change determine the equation to select to
  solve for the unknown.
• All the remaining properties must be held
  constant.

36
Properties of all gases

• KNOW ALL THE FOLLOWING
• Pressure at STP is
• 1 atm 760 mm Hg 101.3 kPa 14.7 lbs/in2
• Volume
• 1 mL 0.001L 1cm3
• Temperature at STP is 273 K (0 Celsius)
• Use Kelvin (not Celsius)

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Combined Gas Law(Temp is in Kelvin)
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Ideal Gas LawPVnRTPrairie Village is not a
Real Town R 8.31 ( LkPa)/(K mol) P, V, Tn
molesR 8.31 ( LkPa)/(K mol)
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Steps1. Known Find the knowns.2. Unknown
Find the unknowns.3. Equation Pick the
equation that matches the knowns and unknowns.4.
Units Make sure units are the same on both
sides. T in Kelvin.5. SigFig Change the answer
to the correct number of significant figures.