[Chapter Two: Matter & Energy ] [2010]
Chapter Two: Matter and Energy
Phase Change Diagram
15
E
10
5
D
0
C
B
-5
A
-10
1. What is the freezing point of the substance represented in this graph?
2. What is the boiling point of the substance?
3. What is the melting point of the substance?
4. What letter represents the range where the solid is being warmed?
5. What letter represents the range where the liquid is being warmed?
6. What letter represents the range where the vapor is being warmed?
7. What letter represents the melting of the solid?
8. What letter represents the vaporization of the liquid?
9. What letter(s) show a change in potential energy?
10. What letter(s) show a change in kinetic energy?
11. What letter represents condensation?
12. What letter represents crystallization?
13. What letter(s) show the molecules moving faster?
14. What letter(s) show the molecules moving farther apart?
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[Chapter Two: Matter & Energy ] [2010]
Section: Energy
Complete each statement below by writing the correct term in the space
provided.
1. The capacity to do work is __________________.
2. A change in matter from one form to another without a change in
chemical properties is a ________________ change.
3. A change that occurs when one or more substances change into a
new substances with different properties is a ____________________
change.
4. A change in matter in which energy is absorbed is a(n)
__________________ process.
5. A change in matter in which energy is released is a(n)
_________________ process.
6. Energy must be added to a solid to melt it. This addition gives the
particles ______________ energy, allowing them to move out of the
crystalline structure.
7. To freeze a substance, energy must be ________________ from the
substance.
Write the answers to the following questions in the space provided.
8. State the law of conservation of energy.
9. What is heat?
10.
Define temperature.
11.
What is the difference between heat and temperature.
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[Chapter Two: Matter & Energy ] [2010]
q = heat energy
Q= m C∆T
m = mass
T = temperature
∆T = (Tfinal – Tinitial)
1. A 15.75-g piece of iron absorbs 1086.75 joules of heat energy, and its temperature
changes from 25°C to 175°C. Calculate the specific heat of iron.
2. How many joules of heat are needed to raise the temperature of 10.0 g of aluminum
from 22°C to 55°C, if the specific heat of aluminum is 0.90 J/g°C?
3. To what temperature will a 50.0 g piece of glass raise if it absorbs 5275 joules of heat
and its specific heat capacity is 0.50 J/g°C? The initial temperature of the glass is 20.0°C.
4. Calculate the specific heat of a piece of wood if 1500.0 g of the wood absorbs 6.75×104
joules of heat, and its temperature changes from 32°C to 57°C.
5. 100.0 mL of 4.0°C water is heated until its temperature is 37°C. If the specific heat of
water is 4.18 J/g°C, calculate the amount of heat energy needed to cause this rise in
temperature.
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[Chapter Two: Matter & Energy ] [2010]
6. 25.0 g of mercury is heated from 25°C to 155°C, and absorbs 455 joules of heat in the
process. Calculate the specific heat of mercury.
7. What is the specific heat of silver metal if 55.00 g of the metal absorbs 47.3 calories of
heat and the temperature rises 15.0°C?
8. If a sample of chloroform is initially at 25°C, what is its final temperature if 150.0 g of
chloroform absorbs 1000 joules of heat, and the specific heat of chloroform is 0.96 J/g°C?
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[Chapter Two: Matter & Energy ] [2010]
Ethanol 101
What is ethanol?
Gasoline is not the only fuel that can power cars! Cars can actually be powered by corn, sugar cane,
wheat, potatoes, cellulosic materials and other feedstocks (unprocessed natural products used in
manufacturing) that are converted into ethanol. Ethanol is a clear, grain alcohol produced from renewable
sources that can be used as fuel. Ethanol (CH3CH2OH) is an organic compound that is considered an
alcohol since it has a hydroxyl group (OH) attached to a carbon.
Pure ethanol is generally mixed with a percentage of gasoline when used as a motor fuel. There are two
common types of ethanol that are used in vehicles- E10 and E85. E10 is a blend of 10% ethanol and 90%
gasoline. All cars are capable of using E10 as fuel. E85, on the other hand, is 85% ethanol and 15%
gasoline. E85 is considered an “alternative fuel” for use in Flexible Fuel Vehicles (FFV’s). These vehicles
can either run on E85 or regular gasoline.
Ethanol is not a new fuel source. Henry Ford’s Model T was designed to run on ethanol.
How is ethanol made?
In simple terms, ethanol is made by fermenting starch or sugar from feedstock, and then distilling it into
alcohol. Most of the ethanol produced in the US is distilled from corn. In Brazil, sugar cane is used to make
ethanol. Ethanol can also be made from cellulosic biomass. Cellulosic materials include corn stalks and
husks, wheat and barley straw, rice or sugar cane bagasse (fibre from crushing the sugar cane), willow and
polar trees, switchgrass, and municipal waste. Cellulosic ethanol is made the same way; however, the
sugars in cellulose are more complex than those found in corn, and need to be separated carefully for the
process to work and require more effort to break down. The ethanol produced by cellulose is the same as
that made from corn.
How much corn does it take to make ethanol?
According to the Department of Energy, it takes one bushel of corn to make 2.5 gallons of ethanol. Since
only part of the corn kernel is used to make the ethanol, one bushel of corn also yields;



1.6 lbs of corn oil
10 lbs of high protein feed
2.6 lbs of corn meal

31.5 lbs of starch used for beverages
and sweeteners
According to the American Coalition for Ethanol, 2.81 billion gallons of ethanol were produced in 2003.
Over the past few years, ethanol production has increased:



2004- 12% of nation’s corn crop was used to produce 3.4 billion gallons of ethanol
2005- 14% of the nation’s corn crop was used to produce 4 billion gallons of ethanol
2006- an estimated 20% of the nation’s crop was used to produce about 5 billion gallons of
ethanol
Approximately 50 million gallons of ethanol are used to make E85.
Does ethanol have a positive net energy balance?
A fuel source has a positive net energy balance if it produces more energy than is required to make it. The
energy needed to create ethanol from corn includes the energy required to grow the corn, and the energy
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[Chapter Two: Matter & Energy ] [2010]
required to convert the corn into alcohol, which most likely involves the use of fossil fuels such as oil or
coal.
According to the Department of Energy, ethanol has a positive net energy balance, that means that it
provides about 25% more energy than is used to make it, including growing the corn, harvesting it, and
distilling it into alcohol. It takes about 0.74 million Btu of “Fossil Energy Input” to yield 1 million Btu of
ethanol.
Why use ethanol as a fuel?
There are many environmental and economic benefits to using ethanol as a fuel source. Ethanol-blended
fuel has a high oxygen content, which enables it to burn more completely and create less pollution. It
reduces the carbon monoxide and hydrocarbon emissions that come from a vehicle’s tailpipe. Likewise,
according to the Department of Energy’s Argonne National Laboratory, ethanol-blended fuels reduced the
CO2 equivalent greenhouse gas emissions by 7.8 million tons in 2005. That’s like removing the
greenhouse gas emissions of over one million cars from the road.
Increasing the use of ethanol-blended fuels produced in the U.S. helps to reduce the country’s dependence
on oil and foreign suppliers. The American Coalition for Ethanol reports that one barrel of ethanol (42
gallons) can displace 1.2 barrels of petroleum at the refinery. While the 4 billion gallons of ethanol produced
in 2005 equals only about 3% of the total U.S. gas consumption for a year ( about 140 billion gallons)
there’s potential for ethanol. The government has suggested a proposal to help reduce present gasoline
consumption by blending it with ethanol and other alternative fuels. The plan seeks for a 20% reduction in
gasoline usage by 2017. Improvements in production, technology, and awareness may yield higher results
in the future.
Is there a downside to ethanol?
The production and use of renewable ethanol-blended fuels is increasing. However, the number of
production facilities and supplies or availability of E85 are currently limited. In addition, while ethanol is
cost-efficient to produce, there is a drawback to E85- there is approximately a 10% decrease in energy per
mile for E85 relative to gasoline, meaning that a car does not get as many miles from a gallon of E85 as it
does from a gallon of gasoline.
Answer the following questions based on the information about ethanol.
1. What is the difference between E10 and E85?
2. In the U.S., what is the primary source for ethanol production? In Brazil?
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3. If it takes one bushel of corn to make 2.5 gallons of ethanol, how many bushels did it take to make
ethanol produced in the U.S. in 2005?
4. What does it mean that ethanol “has a positive net energy balance”?
5. Is ethanol energy efficient to produce? Why or why not?
6. What do you consider to be the pros and cons of using ethanol as a fuel?
Pros
Chapter Two: Matter and Energy
Cons
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[Chapter Two: Matter & Energy ] [2010]
Type
Symbol
Charge
Mass
Alpha particle
α
+2
4
Beta particle
β
-1
0
Gamma Ray
γ
0
0
Alpha emission:
238
4
234
U  He +
Th
92
2
90
Beta emission:
234
0
234
Th 
Pa
e+
90
1
91
Notice that the product of one decay reaction becomes the element that decays (starting point) in the next step.
In a series of 14 steps (the first two are above), Uranium-238, a fuel used in nuclear reactors, decays until it reacts a stable
element. This final element is not radioactive. It will no longer undergo decay. It is stable.
Write radioactive decay reactions for the steps below. What stable element is the U-238 finally converted to?
3. Beta emission
234
Pa  ____________ + ____________
91
4. Beta emission
5. Alpha emission
6. Alpha emission
7. Alpha emission
8. Alpha emission
9. Beta emission
10. Beta emission
11. Alpha emission
12. Beta emission
13. Beta emission
14. Alpha emission
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[Chapter Two: Matter & Energy ] [2010]
HEAT OF VAPORIZATION/FUSION PROBLEMS
1. Calculate the energy required to melt 250 grams of ice.
2. Determine the energy released when 1000 grams of steam is condensed. (2,260,000)
3. If 975 grams of water is frozen, how much energy is released?
4. I am trying to vaporize 225 grams of iodine. How much energy will I need, if the heat of
vaporization for iodine is 0.163 kJ/gram? (36,675)
5. 49.5 grams of water is boiled. How much energy will it take until all of the water is vaporized?
6. How much energy is required to melt 100 grams of iron, if the heat of fusion for iron is 0.25
kJ/gram? (25,000)
7. A 21.0 g sample of water is cooled from 34°C to 28°C. How many joules of heat were removed
from the water? (527.2)
8. An 18.7 g sample of platinum metal increases in temperature by 2.3°C when 5.7 joules of heat are
added. What is the specific heat of platinum?
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[Chapter Two: Matter & Energy ] [2010]
9. The specific heat of silver is 0.24 J/g°C. How much heat must be added to a silver block of mass
86 grams to raise its temperature by 9.0°C? (185.76)
10. How much heat is required to raise the temperature of 68.0 grams of AlF3 from 25°C to 80.0°C?
The specific heat of AlF3 is 0.8948 J/g°C.
11. How much heat is required to raise the temperature of 789 grams of acetic acid,
CH3COOH, from 25°C to 82.7°C? The specific heat of acetic acid is 2.57 J/g°C. (117,000)
12. How much heat is released when 42.8 grams of calcium carbide cools from 74.2°C to 11.5°C?
The specific heat for calcium carbide is 0.982 J/g°C.
13. In order to make tea, 1000 grams of water is heated from 22° to 99°C. How much energy is
needed? (322,168)
MULTISTEP PROBLEMS
1. Calculate the amount of energy required to take 125 grams of H2O from -15C to 45C.
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2. Determine how much energy is release when 67 grams of water at 0C, is frozen, then cooled to
25C. (25,611)
3. I have heated 50 grams of ice from -11C, until it is steam at 125C. How much energy did this
require?
4. How much energy will I need to heat 112 grams of water from 50C to 150C? (287,862)
5. If I cool 18 grams of H2O from 200C to -25C, will I be releasing or absorbing energy? Calculate
how much.
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[Chapter Two: Matter & Energy ] [2010]
FAST WRITE
1. Write as much as you can about how matter and energy are related for three
minutes. Even if you’re stuck keep writing. Write “I’m stuck!” Or "Nothing to write.”
Chapter Two: Matter and Energy
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