CHEM 1030 Fundamentals of Chemistry Fuel for Thought

CHEM 1030 Fundamentals of Chemistry
Case Study for Biofuels - Chemistry Lab
Fuel for Thought
On Friday, September, 19th 2008, Zach headed to the local gas station to get gas before going to his
morning class at Volunteer State. Gas prices had slightly moved upwards for a week. But that morning
gas was $4.69 per gallon and the cars were lined up out into the street. His father and grandfather had
told him of similar stories of gas lines during 1973 and 1979 gas embargoes.
One week earlier Hurricane Ike made its final landfall near Galveston, Texas as a strong Category 2
hurricane. At that time, Hurricane Ike became the third-costliest hurricane ever to make landfall in the
United States, and the costliest hurricane in Texas history. It forced the shutdown of several oil refineries
and crippled some for months. These refineries serve the Southeastern United States.
Zach had $10.00 in his pocket and had thought he could buy at least 4 gallons of gas. However, that
morning his money barely bought 2 gallons of gas.
Several years later Zach graduated with his Bachelor of Science degree in geology from the University of
Tennessee and started his professional career as petroleum geologist and then also became an energy
consultant. Zack reads the following letter that is published in The Tennessean:
Corn should be used as food, not fuel
The Tennessean,
Gerry Calhoun, Dec 1, 2012
Six million children died of starvation last year, while almost 100 million people went hungry. The
cost of animal feed has sent meat and poultry prices spiraling. Yet we burned 40 percent of America’s
corn crop in our cars to the detriment of the poor throughout the world.
Now, the federal government has recommended an increase from 10 percent to 15 or 20 percent of
ethanol in every gas tank. Besides all the carbon dioxide created by converting corn to sugar to
ethanol, the decreased mileage of this diluted gasoline makes drivers buy more fuel, thus canceling
any net reduction of carbon emissions.
So, why do national policies foster rising food prices and global hunger without really decreasing
atmospheric pollution? It seems that Cargill and Arthur Daniels Midland built too many distilleries.
Rather than write off such a mistake, they send legions of lobbyists to Congress to avoid losses by
demanding we use more ethanol. Big Grain exceeds Big Oil in its lack of shame in pursuing obscene
profits.
Making matters worse, the summer drought eliminated as much as a tenth of this year’s corn harvest,
pushing prices above $7 a bushel. At that level, it simply becomes too expensive for the world’s poor.
Adapted from the Boyce Thompson Institute, CDW and Genecor
Parris Powers and Douglas Williams, Volunteer State Community College, Gallatin, TN
10.22.2014
U.S. taxpayers unwittingly fostered malnutrition and even starvation by allocating $6 billion for corn
subsidies in 2011.
Another potential global disaster is the palm oil stampede. In Indonesia, areas the size of Maine long
covered by rain forests are being burned. About 30,000 more square miles are poised to join the
inferno because lucrative sales of palm oil have trumped biodiversity. Furthermore, burning the trees
and then draining the bare peat soil releases immense quantities of greenhouse gases — about 558
million metric tons by 2020.
Like alternatives to palm oil, alternatives to corn-based ethanol also exist. In Brazil, sugar cane
already powers flex-fuel automobiles, and here in the U.S., sugar beets can produce twice as much
ethanol per acre as corn. Such sources offer greater efficiency because neither involves the extra
expense and CO2 generation of an initial conversion to sugar before their conversion to ethanol.
The U.S. has already lowered its carbon footprint more than any other developed country. Reducing
coal for power plants from over 50 percent to 39 percent, and increasing natural gas from 20 percent
to 31 percent, has radically cut emissions because gas releases only half as much CO 2 as coal. Also, the
cheaper price of gas, thanks to abundant supplies generated by fracking and horizontal drilling, has
pared the cost of producing electricity.
We do not need to starve children or burn rain forests or subsidize Big Grain to reduce CO 2 emissions.
Such draconian measures actually harm rather than protect the world.
Now if someone would just figure out how to turn kudzu and switchgrass into food or fuel.
As a partner with the National Science Foundation initiative – Collaborative
Research: Community College Undergraduate Research (CCURI), several
students at Volunteer State have begun such investigations, looking at
switchgrass and kudzu as potential renewable biofuels to replace the use of
corn. In CHEM 1030 this semester, we will look at several of their methods
and continue this investigation.
Adapted from the Boyce Thompson Institute, CDW and Genecor
Parris Powers and Douglas Williams, Volunteer State Community College, Gallatin, TN
10.22.2014
Switchgrass: From Biomass to Biofuel
Student Pre-Lab Assignment
The Big Picture: Think about how much energy you and your family use in a day. Between heating and using
electricity in homes and schools and using gas to drive around, most of us use quite a bit of energy on a daily basis.
Much of this energy comes from oil and other non-renewable sources. However, due to the high costs of these
energy sources, and the negative impacts they have on the environment, biofuels are being investigated as renewable
fuel alternative. In the Tennessee Valley region, where the climate is moist and humid, plants grow easily and
produce lots of biomass. If we can meet some of our regional energy needs with locally produced plant materials,
which are renewable resources, than we can better protect our environment. Before we can meet our regional
energy needs with plant materials, we need to figure out the most efficient way to release glucose (sugar) from plant
cell walls and use that glucose to produce biofuels for our transportation needs in the Southeast Region. Many
people in Tennessee and neighboring states are figuring out how to use switchgrass and other indigenous plants to
make gas and other products. You can get involved too.
The Problem: Plant cell walls are strong and rigid and difficult to
break apart. If you have ever been in a forest and seen fallen trees
and decaying plant material, you know it takes a very long time for
plant material to break down. This material, known as cellulose, is
made up of long chains of tightly bound glucose molecules. In
order to make biofuels from cellulose, the long cellulose chains need
to be broken down into individual glucose molecules. Then
microbes ferment the glucose molecules. Fermentation produces gas
and in this case, ethanol gas is produced.
The Investigation: In this lab we will try to find the best way to
break down cellulose into glucose using a promising biofuel plant
called switchgrass. This is still a new science because no one has figured out a cheap and quick way to do this on a
large scale.
1.
How do you think cellulose is broken down in nature? (Think of the steps involved in a tree decaying in
the forest)
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
______________________________________________________________________________________
2. List some environmental factors that might speed up the process of breaking down cellulose in nature.
a.
b.
c.
Adapted from the Boyce Thompson Institute, CDW and Genecor
Parris Powers and Douglas Williams, Volunteer State Community College, Gallatin, TN
10.22.2014
Laboratory Preview
In this lab, we will treat switchgrass with an enzyme to breakdown cellulose in the cell walls into glucose molecules.
The enzyme is actually a mixture of enzymes made by fungi and bacteria and called a cellulose complex. We will
do three chemical pre-treatments (H2SO4, HCl or KOH ) on the switchgrass before adding the enzyme complex to
figure out which pre-treatment or combination of pre-treatments allows the enzyme to break down the most
cellulose into glucose.
1. Mechanical Pre-Treatment
A. Whole Grass-Pieces of switchgrass that have been cut into 1 mm long grass pieces.
Question: Does the size of the switchgrass effect how much glucose will be produced?
Hypothesis (Be sure to explain why this is your hypothesis):____________________________________________
_____________________________________________________________________________________________
_____________________________________________________________________________________________
_____________________________________________________________________________________________
_____________________________________________________________
2. Chemical and Heat Pre-Treatment
A. Four of the samples will be heated in hot water for 10 minutes.
B. Each sample will be cooled to room temperature.
Question: Will heating switchgrass and allowing it to cool to room temperature before adding the enzyme effect
how much glucose will be produced? If so ,how? Which chemical (H2SO4, HCl or KOH) will provide the largest
chemical impact in breaking down the cell wall?
Hypothesis (Be sure to explain why this is your hypothesis):_____________________________________________
_____________________________________________________________________________________________
_____________________________________________________________________________________________
_____________________________________________________________________________________________
_____________________________________________________________
Adapted from the Boyce Thompson Institute, CDW and Genecor
Parris Powers and Douglas Williams, Volunteer State Community College, Gallatin, TN
10.22.2014
CHEM 1030
An Experimental Design and Investigation
Switchgrass Labs: From Biomass to Biofuel
Materials:
Switchgrass pellets
Stirring rod
Balance and weigh
boats/paper
Marker/Tape
Hot Plate
1.0 M HCl (aq)
Mortar/Pestle
Distilled Water
1.0 M H2SO4 (aq)
1 beaker per group (200 mL
or larger)
20 mL test tubes (8 per
group of 2 students) with a
test tube rack
1.0 M KOH (aq)
0.5 mL disposable Pasteur
pipette
Chemstrips Glucose test
strips
RID-X © broth
Part 1 for Week 1
A. Procedures for all samples:
1. Get Organized:
Student in groups of 2 works best. Each group needs 1 test tube rack, 8
test tubes, marker, stirring rod, switchgrass pellet samples, hotplate, 200mL
beaker that is 1/3 full of water, and 0.5 mL disposable Pastuer pipettes.
Weigh out approximately 1.000 gram of switch grass pellets; crush pellets
with a mortar and pestle. Access to water, enzyme complex (week 2) and
electronic balance are available.
2. Set-Up Experiment:
Use your marker/or labels to label your tubes. (Where the label says “Date”
you should write the experiment’s date. And where the label says initials
place the initials of each student). See matrix that follows.
Adapted from the Boyce Thompson Institute, CDW and Genecor
Parris Powers and Douglas Williams, Volunteer State Community College, Gallatin, TN
10.22.2014
Tube
Number
Label
Tube
Number
Label
1
Grass/Heat/HCl/Date/Initials
5
Grass/Heat/KOH /Date/Initials
2
Grass/No-Heat/HCl/Date/Initials
6
Grass/ No-Heat/KOH /Date/ Initials
3
Grass/Heat/H2SO4 /Date/Initials
7
Grass/Heat/ No chemical/Date/Initials
4
Grass/No-Heat/ H2SO4 /Date/Initials
8
Grass/No-Heat/ No chemical/Date/Initials
4. Bring the rack and test tubes to the weigh stations and mass 0.100 grams of
switchgrass to place in each of the 8 test tubes. Use weighing paper that is
diagonally creased I massing the samples. All eight test tubes will get 0.100
gram each of switchgrass. You may need to use a glass stirring rod to push
down the crushed switchgrass pellets to the bottom of the test tube.
RETURN UNUSED SWITCHGRASS TO YOUR INSTRUCTOR.
5. Using a Pasteur pipette place each of the chemical reagent into the
appropriately labeled test tubes. For test tubes labeled 1 & 2 you will place
20 drops of 1.0 M HCl. For test tubes labeled 3 & 4 place 20 drops of 1.0M
H2SO4. And for test tubes labeled 5 & 6 place 20 drops of 1.0M KOH. Then
add 20 drops of distilled water to each the test tubes, 1-6. Add 40 drops of
distilled water to test tubes 7 & 8. Agitate each test tube to mix switchgrass
with chemical in the test tube, 1-8. You may want to use a stirring rod to
mix. If you do, please rinse the stirring rod with distilled water each time
to prevent cross contamination of the chemicals.
B. Heat Pre-Treatment:
1. Make sure your beaker is 1/3 full of distilled water and place it on the hot
plate to heat to boiling. Add two or three boiling stones to the beaker.
2. Carefully place the four test tubes labeled” heat” into the beaker of the
boiling water. Allow samples to sit in the gently boiling water for 15 minutes
3. Once the test tubes are cool enough to touch, carefully cap (wrap) at the
mouth of all eight test tubes with paraffin wax paper. Place the eight test
tubes into the rack and store in a place that is determined by your
instructor. The test tubes will set for one week allowing for the chemical pretreatments to work.
Adapted from the Boyce Thompson Institute, CDW and Genecor
Parris Powers and Douglas Williams, Volunteer State Community College, Gallatin, TN
10.22.2014
Questions to consider:
Of the eight test tubes and reaction mixes you developed, which are considered to contain a
solution?
After the 20 drops of distilled water is added to each test tube, what is the molarity and each
chemical (HCl, H2SO4, KOH)?
What is the solvent in all 8 test tubes?
In which test tubes will the switchgrass dissolve? Why or Why not?
By definition, what is a solution? Does this always involve or require a chemical reaction?
What important features about aqueous solutions provide for chemical reactivity?
Does the fact that the Human Body is 70% water affect metabolism? Why or Why not?
Adapted from the Boyce Thompson Institute, CDW and Genecor
Parris Powers and Douglas Williams, Volunteer State Community College, Gallatin, TN
10.22.2014