chapter 6: the states of matter suggested problems:
TRANSCRIPT
![Page 1: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/1.jpg)
Chapter 6: The States of Matter
Suggested Problems:
![Page 2: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/2.jpg)
States of Matter• ______
– Definite volume and shape• ______
– Definite volume but not shape
• Takes the shape of its container
• _______– No definite volume or shape
• Will not only take the shape of its container it will fill it completely
![Page 3: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/3.jpg)
Solids• A __________ state of matter• Atoms (or molecules) are “touching”• Strongest intermolecular forces
– Hold atoms (or molecules or ions, etc.) rigidly in a 3D crystalline lattice
![Page 4: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/4.jpg)
Liquids• Also a __________ state of matter• Atoms (or molecules) are “touching”• Intermolecular forces hold atoms (or
molecules) in contact, but not rigidly in place…molecules can slide past each other
![Page 5: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/5.jpg)
Gases• Virtually ___ intermolecular forces• Gaseous molecules (etc.) comprise a very small
percent of the sample volume• Gaseous molecules are in constant random
motion…the velocity is related to temperature• Molecules collide with walls of container and
with each other and bounce off with no loss of energy
![Page 6: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/6.jpg)
Properties of Gases• Gases are the best understood state of
matter, because we ignore intermolecular forces
• The volume a gas sample occupies is a function of three variables:– ___________– ___________– ___________
![Page 7: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/7.jpg)
Pressure
• Pressure is force per unit area• Units of pressure:
– Pounds per square inch– Torr or mmHg– Atmosphere
1 atm = 760 torr = 760 mmHg = 14.7 psi
![Page 8: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/8.jpg)
Measuring Pressure: Barometer
air pushing downgravity pulling down
![Page 9: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/9.jpg)
Pressure Conversion Example• The gauge on an oxygen gas cylinder
reads 1272 psi. Express this in atm and torr. (1 atm=14.7 psi)
![Page 10: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/10.jpg)
Volume of a Gas
• Imagine a fixed amount of air at a given temperature and pressure in a balloon
• What will happen to the volume if we add more air?
![Page 11: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/11.jpg)
Volume of a Gas• Imagine a fixed amount of air
at a given temperature and pressure in a balloon
• What will happen to the volume if we squeeze the balloon (increase pressure)?
![Page 12: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/12.jpg)
Volume of a Gas• Imagine a fixed amount of air
at a given temperature and pressure in a balloon
• What will happen to the volume if we increase the temperature?
![Page 13: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/13.jpg)
The Combined Gas Law
• P is pressure• V is volume• T is ________
temperature• n is number of moles
22
22
11
11
Tn
VP
Tn
VP
![Page 14: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/14.jpg)
The Empirical Gas Laws
• Boyle’s Law– Volume is inversely proportional to pressure
(constant n and T)• Charles’s Law
– Volume is directly proportional to the Kelvin temperature (constant n and P)
• Avogadro’s Law– The volume of a gas is directly proportional to the
number of gas moles (constant T and P)
![Page 15: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/15.jpg)
Boyle’s Law: Example
• 15 liters of argon is collected at an initial pressure of 1.05 atm. If the gas is compressed to a new pressure of 1510 torr, what is the new volume?
![Page 16: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/16.jpg)
Charles’s Law: Example
• The temperature of 35.6 mL of neon is increased from –35.4ºC to 75.2ºC. What is the new volume?
![Page 17: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/17.jpg)
Combining Boyle’s and Charles's Laws
• A bubble of air having a volume of 75.0 mL is released from 35 feet under the sea (where the pressure is 2.07 atm and the temperature is 18 ºC). What will the new volume be at the surface, where P=0.967 atm and T=23 ºC?
![Page 18: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/18.jpg)
The Ideal Gas Law• Combines the elements of the ________ gas
laws
R constant Tn
VP
Tn
VP
22
22
11
11
Kmol
atmL0.0821R
nRTPV
![Page 19: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/19.jpg)
Standard Conditions
• STP = standard temperature and pressure
T = _____ K (_____ ºC)
P = _____ atm = ____ torr
![Page 20: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/20.jpg)
Example
• What volume will 2.0 grams of helium occupy at a temperature of 290K and a pressure of 800 torr?
![Page 21: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/21.jpg)
Which Gas Law to Use?
• Use the combined gas law when the problem describes two sets of conditions– the pressure and/or temperature changes
• Use the ideal gas law when there are a single set of conditions
![Page 22: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/22.jpg)
Emptycontainer
Oxygen0.25 atm
Nitrogen0.75 atm
Dalton’s Law of Partial Pressures
• The ______ pressure of a gaseous mixture is the sum of the partial pressures
Nitrogen0.75 atm
Oxygen0.25 atm
Ptotal =
![Page 23: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/23.jpg)
Graham’s Law• __________ is net movement of a gas from an
area of high concentration (pressure) to an area of lower concentration
• __________ is the movement of a gas through a pinhole
• Both Diffusion and Effusion follow Graham’s Law
1
2
2
1
MW
MW
Rate
Rate
Rate is an amount per time
![Page 24: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/24.jpg)
Graham’s Law Example
• Oxygen Molecules weigh 16 times as much as hydrogen molecules. Which molecule will diffuse faster and how much faster?
![Page 25: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/25.jpg)
Changes of State
GasGas
LiquidLiquid SolidSolidfreeze
melt
condensesublimevapo
rize
cond
ense
What do all of these changes in state have in common?
![Page 26: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/26.jpg)
Energy
• Energy is the ability to do work– Kinetic Energy: energy due to motion
– _________ Energy: stored energy
– Heat Energy: the sum of the kinetic and potential energies of molecules in a sample
![Page 27: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/27.jpg)
Energy and Its Units
• calorie (cal): is the amount of heat needed to raise the temperature of 1 gram of water by 1 degree Celsius at 15 oC
• kilocalorie = 1000 cal• A food Calorie = 1000 cal• Joules (J): are the metric unit of energy
1 cal = 4.184 J
![Page 28: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/28.jpg)
Energy Conversion Example
• A candy bar has 350 Calories. How many joules does one candy bar contain?
![Page 29: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/29.jpg)
Heat and Temperature
• __________: is a measurement of the average kinetic energy of the molecules in a sample– ___ is measured in degrees with a
thermometer• _______: is the sum of the kinetic (and
potential) energies in a sample– _____ is measured in calories with a
calorimeter
![Page 30: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/30.jpg)
Calorimeters
Bomb Calorimeter
Coffee Cup Calorimeter
![Page 31: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/31.jpg)
Specific Heat• Specific heat (SH) is the amount of heat needed
to raise the temperature of 1 gram of material by one degree Celsius
)T (T T
heat q
Tmass
q SH
T)((mass)(SH) q
IF
![Page 32: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/32.jpg)
Specific Heat Example
• A 10.0 gram sample of copper at 25 ºC has a final temperature of 100 ºC when 289 J of heat are added. What is the specific heat of copper? (SH of liq water = 4.18 J/goC)
![Page 33: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/33.jpg)
Distribution of Energy
• In a sample of material, the kinetic energies of the molecules follow a Boltzman Distribution:
Kinetic Energy
# M
olec
ules
Average KE
velocity v
mass m
mv2
1 KE 2
![Page 34: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/34.jpg)
Kinetic Energy Distribution
Kinetic Energy
# M
olec
ules
ThighTlow
![Page 35: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/35.jpg)
Changes of State
GasGas
LiquidLiquid SolidSolidfreeze
melt
condensesublimevapo
rize
cond
ense
![Page 36: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/36.jpg)
Vaporization
• The most energetic molecules in a liquid have sufficient kinetic energy to escape into the ____ phase
• Once the molecules are free as gases, they exert a pressure– This is called the ______ pressure
• How does vapor pressure depend on temperature?
![Page 37: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/37.jpg)
Vapor Pressure of Water and Ethanol
0
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
7 0 0
8 0 0
9 0 0
1 0 0 0
0 2 0 4 0 6 0 8 0 1 0 0
T e m p e r a t u r e ( o C e l c i u s )
Vap
or P
ress
ure
(Tor
r)
v a p o r p r e s s u r e o f
w a te r
v a p o r p r e s s u r e o f
e th a n o l
![Page 38: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/38.jpg)
Boiling Point
• The boiling point of a liquid is the temperature where the vapor pressure equals the ambient pressure.
• The _______ boiling point of a liquid is the temperature where the vapor pressure equals 760 torr.
• How does boiling point depend on pressure?
![Page 39: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/39.jpg)
Changes of State
GasGas
LiquidLiquid SolidSolidfreeze
melt
condensesublimevapo
rize
cond
ense
What do all of these changes in state have in common?
![Page 40: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/40.jpg)
Freezing/Melting Point
• The melting point of a substance is the temperature at which a crystalline solid changes to a liquid.
• What is the difference between melting point and freezing point?
![Page 41: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/41.jpg)
Energy Changes and Changes of State
• Imagine recording the temperature of an 18 gram (i.e., 1.0 mole) sample of ice at -40ºC as heat is added
No T
No T
heat added, kJ temperature0.0 -401.5 07.5 0
15.0 10055.7 10056.5 120
![Page 42: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/42.jpg)
0 10 20 30 40 50 60-40
-20
0
20
40
60
80
100
120
kilojoules of heat added
Tem
p (o
C)
Heating Curve for 1 Mole of Water
Water is boiling:Heat of vaporization
40.7 kJ/mol
Ice is melting:Heat of fusion
6.02 kJ/mol
![Page 43: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/43.jpg)
Molar Heat of Fusion
· DHºfus is the heat required to convert one mole of solid to a liquid at at its normal melting point
· DHºfus represents the energy needed to break down intermolecular forces and allow molecules to slide around the liquid phase
![Page 44: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/44.jpg)
Molar Heat of Vaporization
· DH°vap is the heat required to convert one mole of liquid to a gas at at its normal boiling point
· DH°vap represents the energy needed to break intermolecular forces and allow molecules to escape into the gas phase
![Page 45: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/45.jpg)
Putting it all Together
• How much heat is required to convert an 18 gram piece of ice at -40 oC to steam at 120 oC?
![Page 46: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/46.jpg)
0 10 20 30 40 50 60-40
-20
0
20
40
60
80
100
120
kilojoules of heat added
Tem
p (o
C)
Heating Curve for 1 Mole of Water
Heat of fusion6.02 kJ/mol
Heat of vaporization40.7 kJ/mol
A
B
C
D E
SH ice = 2.1 J/goCSH liq = 4.18 J/goCSH gas = 2.0 J/goC
q = m(SH)(T)
![Page 47: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/47.jpg)
Question
• Explain why orange growers spray their trees with water when there is a threat of freezing temperatures.
![Page 48: Chapter 6: The States of Matter Suggested Problems:](https://reader036.vdocuments.site/reader036/viewer/2022062300/56649cc15503460f949891c3/html5/thumbnails/48.jpg)
Question
• Why does steam at 100ºC cause more severe burns than water at the same temperature?