Tuesday, May 17, 2011

Exam Review #16

16)    Predict the products of the following reactions and write balance chemical equations:
a.     The incomplete combustion of propane (C3H8
b.     Solutions of potassium bromide and lead (II) nitrate are mixed. (include net ionic equation)
c.     Chlorine gas is bubbled into a solution of potassium iodide ( include net ionic equation)
d.     Dinitrogen trioxide gas is passed over water
e.     Solid copper (II) oxide is added to water
f.      The reaction of nitric acid with potassium hydroxide solutions (include net ionic equation)
g.     Aluminum phosphate is strongly heated
h.     A piece of silver metal is added to a solution of aluminum nitrate
i.      Solid barium chlorate is heated in the presence of magnesium dioxide as a catalyst.
j.      Solutions of magnesium sulfate and copper nitrate are mixed (include net ionic equation) 

Thursday, April 7, 2011

Chernobyl Incident

History of Chernobyl.
The Chernobyl Power Complex was fueled by four RBMK-1000 nuclear reactors.  The Chernobyl Power Complex was located in Ukraine, 80 miles (130 km) north of Kiev.  The first and second reactors were built in 1970 and 1977, respectively, and the third and fourth reactors were constructed by 1983.  The radioactive waste from the reactors was stored in an artificial tank covering 8.5 square miles (22 square km).  The complex was in the middle of building two more reactors when something went horribly wrong.  On April 26, 1986, a flawed Soviet design and unacceptable action and judgment of personnel who did not act according to duty under the absence of safety regulation, caused the nuclear disaster.  The Chernobyl Power Complex was built during the Cold War, when there was great tension between Communist Russia and the United States after WWII, which caused a race for nuclear power technology advancement and application during a time of political and military threat as well as fear-induced propaganda. 
 What went wrong at Chernobyl?
Engineers at Chernobyl decided to conduct an experiment to see if the cooling pump system could continue to function using power generated by the reactor should the outside power source fail.  They lowered the graphite control rods into the reactor decreasing the energy output supplying the national grid to about 20% of the usual amount.  However, they miscalculated the drop in power and the nuclear reactor nearly shutdown.  To compensate, the engineers frantically began to raise some of the control rods to increase the power output.  However, the power levels were too low to run the pumps of the cooling system.  They raised more rods, and then the power levels quickly and unexpectedly increased to dangerously high levels.  Ironically, the reactor overheated and the water coolant turned to steam.  The emergency stop button was pushed, however, the additional control rods displaced the remaining coolant and concentrated reactivity.  At this point, fuel pellets exploded, rupturing the fuel channels.  A large explosion occurred which blew off the reactor roof.  Carbon monoxide burned for nine days, and a large amount of radiation was released into the atmosphere.

What are the long-term effects of Chernobyl?
Childhood thyroid cancer is probably the main long-term health effect of the Chernobyl accident.  Iodine is readily concentrated in the thyroid gland.  Cows initially took up radioactive iodine.  The dairy animals produced milk that was consumed by children, causing thyroid cancer.  Epidemiologists study the causes of disease in populations.  They have debated whether the incidents of various diseases have been higher in the populations exposed to the nuclear fallout of Chernobyl compared to the general population.  There appears to be a higher incidence of cataracts in children and in workers exposed to the radiation.  There appears to be no change in the fertility of either men or women, however, there was an increase in congenital deformities.  In addition, the trauma of the accident has caused long-term psychological problems in many people.  Lichens readily absorb radioactive material from the environment.  In Scandinavia, reindeer that eat lichens exhibit increased levels of radioactivity as well as the Sami people who hunt and feed on the reindeer.  A 30 km radius around Chernobyl is still referred to as the “Dead Zone.”  Dangerous levels of radioactivity will persist for generations. 
How does a nuclear reactor work?
Nuclear power plants are made with one motive, to produce electricity in a clean reaction.  The nuclear reaction at the core of a nuclear power plant produces heat, which creates steam that powers a turbine.  The turbine is a generator that produces electricity.  The heat to make steam is produced by the spontaneous fission of U-235 that produces fissionable products as well as neutrons.  Einstein’s famous equation, E=mc2, states that mass is convertible to energy.  Basically, if you add up the mass of the products of fission, they are slightly less than the mass of the original U-235.  This small amount of mass, 0.1%, is converted into energy.  Even though the mass is very small, it is multiplied by the square of the speed of light, which is a huge number.  The energy released is in the form of gamma rays.  The neutrons released collide with other atoms, creating a chain reaction.  Most naturally occurring uranium is U-238 and only 0.7% is U-235.  In order to make a reactor efficient, the uranium is enriched to 3-4% U-235.  When a neutron hits U-235, it readily undergoes fission and splits, releasing more neutrons and energy.  The chain reaction becomes exponential.  Also, when U-238 collides with a neutron, it is converted to plutonium-239.  When plutonium-239 collides with a neutron, it also undergoes fission and releases energy.  In order to prevent the chain reaction from going out of control, graphite rods are raised and lowered into the reactor to absorb some of the neutrons created by fission.  Water is pumped through the reactor in pipes, absorbing the heat produced by the nuclear reaction.  This serves two important functions.  First, the energy is removed from the reactor and is converted into steam and ultimately electricity, which is the purpose of the reactor.  Second, this process “cools” the reactor, preventing damage and possible melting of the uranium metal.

People affected by the accident.
The commercial Chernobyl Power Plant accident has been the only circumstance of radiation fallout causing fatalities.  The events of April 1986 caused the direct death of 28 power-plant workers and firemen who were either present during the initial blast or were involved in the cleanup or containment of the nuclear material.  Of the thousand professionals who worked to contain the disaster, 134 people were diagnosed with Acute Radiation Syndrome (ARS).  No one who was off-site of the explosion suffered from ARS.  However, from the strict radiation control area that contained a population of 216,000, there was a steep increase in thyroid cancers among children that can be attributed to exposure to radioactive iodine fallout from the radiation clouds.  ARS occurs when a large part of the body is exposed to an intense dose of radiation in a short period of time.  The radiation must be able to penetrate through the body in order to harm internal organs and bone marrow.  Immediate symptoms and signs of ARS include reddening of the skin or a rash, swelling, itching and hair-loss.  Radiation poisoning can cause nausea, vomiting, loss of appetite and diarrhea.  After a short time, the affected person may heal and recover or can relapse and suffer from comas or seizures.  Essentially what happens is that the cells of the bone marrow are killed causing internal bleeding that can easily lead to infection. 
Reaction to Chernobyl accident.
Soon after the accident, the nuclear reactor was covered in concrete and lead to serve as a temporary solution to contain the radioactive mass, allowing the plant to continue to produce electricity.  By 2014, a new, more permanent structure will be in place.  The major issue of the Chernobyl accident is that 200 tons of radioactive material remains in the reaction chamber, which poses a threat to the environment.  Western designs and more recently constructed nuclear reactors have been made in a way that in a time of similar disaster, the radioactive material can be easily contained to prevent radioactive leaks into the atmosphere.  This was a key factor in the Three-Mile Island accident in which no deaths occurred as a result of the core meltdown. 
Japanese reactors could pose a threat to health and environment.
On March 11, 2011 a massive earthquake occurred near the coast of Japan.  Shortly thereafter, a tsunami ravaged the coast with destruction.  Unfortunately, several of Japan’s nuclear power plants are located very near this seacoast.  A double power failure caused a malfunction of the cooling pumps, creating increased heat in the reaction chamber.  In addition, as a result of the earthquake and subsequent tsunami, there is concern about the integrity of the containment structures.  There has been controversy regarding the possibility of a disastrous meltdown of the nuclear core.  Thus far, released radiation levels have been greater than those of Three-Mile Island, but much less than the disaster in Chernobyl.  In the cases of Chernobyl and Three-Mile Island, the disasters were caused by human error, miscalculation, and poor planning.  However, in the case of the Japanese reactors, the disaster was caused by a sudden and unexpected natural disaster.  In addition, there has been criticism of the Japanese placement of a cluster of nuclear power plants right on the seacoast in an area known to be geologically vulnerable to earthquakes.  In all three disasters, the concern has been loss of control of the reaction with resulting thermal meltdown, explosion, and release of deadly radiation into the environment.  This problem of control is inherent in the physics and chemistry of the nuclear chain reaction.

Japan Nuclear Reactor Explosion (VIEW EXPLOSION HERE!)

Should we be concerned?
The economies of the world have become increasingly dependent on sources of energy to produce electricity.  All of these sources of energy, including fossil fuels, hydroelectric power, wind power, solar power, and biological fuels, have hazards associated with their production and use.  Nuclear power obviously is no exception.  Nuclear power is produced in hundreds of plants in varying locations around the world, some of which are politically unstable.  In Einstein’s equation, as stated above, the square of the speed of light (c2) is a huge number representing the enormous potential dangers of nuclear power.  A nuclear catastrophe can be disastrous to a large area surrounding the nuclear plant, making the environment unusable for generations.  In addition, a localized disaster can have environmental and health effects felt throughout the world.  Although I see the enormous potential of nuclear power to solve many of our energy problems and needs, I am concerned about our ability, as humans, to use it safely.

Works Cited
"BBC NEWS | In Depth | Chernobyl." BBC News - Home. Web. 07 Apr. 2011. <http://news.bbc.co.uk/2/shared/spl/hi/guides/456900/456957/html/nn2page1.stm>.
"CDC Radiation Emergencies | Acute Radiation Syndrome." CDC Emergency Preparedness & Response Site. 10 May 2006. Web. 06 Apr. 2011. <http://www.bt.cdc.gov/radiation/ars.asp>.
"Celebrate Socialism Success Story with Nancy Pelosi." The People's Cube - Political Humor & Satire. Web. 06 Apr. 2011. <http://thepeoplescube.com/current-truth/celebrate-socialism-success-story-with-nancy-pelosi-t6406.html>.
"Chernobyl | Chernobyl Accident | Chernobyl Disaster." World Nuclear Association | Nuclear Power - a Sustainable Energy Resource. Web. 06 Apr. 2011. <http://www.world-nuclear.org/info/chernobyl/inf07.html>.
"Chernobyl Disaster Effects." Wikipedia, the Free Encyclopedia. Web. 06 Apr. 2011. <http://en.wikipedia.org/wiki/Chernobyl_disaster_effects>.
Rebels', Libyan. "Brave Japanese Chopper Crews Drop Water on Reactors." Politically Confused. Web. 06 Apr. 2011. <http://politically-confused.blogspot.com/2011/03/brave-japanese-chopper-crews-drop-water.html>.
Soonawala, Nash. "The Long-Term Effects of the Chernobyl Accident | EHow.com." EHow | How to Videos, Articles & More - Trusted Advice for the Curious Life | EHow.com. Web. 07 Apr. 2011. <http://www.ehow.com/info_8131701_longterm-effects-chernobyl-accident.html>.
"Three Mile Island Emergency." Three Mile Island. Dickinson College, 2007. Web. 7 Apr. 2011. <http://www.threemileisland.org/science/howitworks/index.html>.
"Worst Nuclear Accidents / Disasters in History." Top 10 Lists - Hot and Weird - SmashingLists. Web. 06 Apr. 2011. <http://www.smashinglists.com/worst-nuclear-accidents-disasters-in-history/>.
"YouTube - Video of Blast at Fukushima Nuke Plant, Radiation Leak Reported." YouTube - Broadcast Yourself. Web. 07 Apr. 2011. <http://www.youtube.com/watch?v=kjx-JlwYtyE>.

Thursday, February 3, 2011

Fun Chemistry!

Covalent Compound Haiku

Covalent Compound
the negative particles
are shared together

Bonding Structure in Everyday Life

linear- Hot dog

bent- Fortune Cookie

trigonal pyramidal- Tripod

trigonal planar- Sail

tetrahedral- Wendy's Sour Cream

Thursday, December 16, 2010

If Your Cat Took Chemistry, Would She Eat This Stuff? -Why not?

Crystal Light® Iced Tea Mix
1. -magnesium oxide MgO


Clif­­® Bar Spiced Pumpkin Pie flavor
2. -calcium carbonate CaCO3
3. -chromium(II) OR (III) chloride CrCl2 OR CrCl3
4. -potassium iodide KI

Minute Maid®­ 100% Juice Fruit Punch
5. -potassium phosphate K3PO4
Red Bull® Energy Drink
6. -magnesium carbonate MgCO

RID® Egg & Nit Comb-Out Gel
7. -water H2O
8. -sodium phosphate Na3PO4
9. -sodium chloride NaCl
CVS® Milk of Magnesia
10. -magnesium hydroxide Mg(OH)2
Purina® Fancy Feast Tuna Feast Flaked
11. -potassium chloride KCl
12. -calcium phosphate Ca3(PO­4­­)2
13. -zinc sulfate ZnSO4
14. -sodium nitrite NaNO2
15. -copper(I) or (II) sulfate CuSO4 OR CuSO4
16. –manganese(II) sulfate MnSO
Walgreens® Hydrogen Peroxide 3%
17. -hydrogen peroxide H2O2
Campbell’s Soup at Hand®
18. -ferrous sulfate FeSO4 

Clabber Girl®­ Baking Powder
19. -sodium aluminum sulfate NaAl(SO4)2

Sensodyne® Pronamel®
20. potassium nitrate KNO3
21. sodium fluoride NaCl


Wednesday, October 6, 2010

JJ Thomson's Experiments with Cathode Ray Tubes

Joseph John (JJ) Thomson was born in Cheetham Hill, England in 1856.  He studied at Cambridge University where he was given the title Cavendish Professor of Experimental Physics as well as Honorary Professor.  In 1906, he won the Nobel Prize in Physics "in recognition of the great merits of his theoretical and experimental investigations on the conduction of electricity by gases."

A cathode ray tube can be defined as a phosphor-coated glass tube from which the air has been removed.  It contains two electrodes, a cathode which is the negative electrode, and an anode which is the positive electrode.  When a high voltage electrical current is applied between the electrodes, a cathode ray travels from the cathode to the anode.  The interaction of the cathode ray with the phosphor-coated glass tube produces green light, the visible cathode ray.

Experiment 1:  JJ Thomson’s objective in his first experiment was to prove that the rays emitted from the cathode were inseparable from their negative charge.  In his first experiment, JJ Thomson built a cathode ray tube with a metal cylinder on its end, containing two slits that led to electrometers.  These electrometers were used to measure electric charges in miniscule amounts.  While conducting this experiment, Thomson realized that when he applied a magnetic field across the tube, the electrometers did not measure any charge from the cathode ray.  From this result, he concluded that the cathode ray was charged and had been deflected by the magnet showing that the charges and rays were intertwined and inseparable.

Experiment 2:  JJ Thomson tried to prove that the cathode rays carried a negative charge.  Thomson improved the quality of his cathode ray tube and its vacuum.  On the tube he placed metal plates, one positively charged, and the other negatively charged.  The rays were deflected by the electric plates.  The positively charged plate attracted the rays, and the negatively charged plate repelled the rays.  From these results, Thomson was able to conclude not only that charges were bound to the rays, but also that the rays consisted of negatively charged particles, “corpuscles,” later renamed electrons.

Experiment 3:  Thomson wanted to learn more about the characteristics of the electrons.  Thomson measured the charge and mass of the particles by determining how much the cathode rays were bent by electrical currents of varying strengths.  From his third experiment, Thomson learned that the charge to mass ratio of the particles was very large.  This result meant that either the charge of the particle was very large, or the mass of the particle was very small.  He deduced that the electron’s mass was very small, and that the electron was part of the atom itself. 

The electrons discovered by Thomson carry a charge of (–1) and have 1/2000 the mass of a hydrogen atom.  The electron was the first discovered subatomic particle.  Also, no matter what metal was used for the cathode, the rays always traveled in straight lines, could be deflected by magnetic fields, and had the same properties.  Thomson was surprised because this meant that atoms could be broken up into smaller parts, contrary to Dalton’s theory.  

Works Cited 
Cath7.jpg. N.d. Reich Chemistry. Tangient, 2010. Web. 6 Oct. 2010. <https://reich-chemistry.wikispaces.com/‌Fall.2008.MMA.Cushman.Hutchinson.Timeline>.

cathode2.jpg. N.d. rwshocker. N.p., n.d. Web. 6 Oct. 2010. <http://rwshocker.com/‌chem_html/‌atomic_stuct.html>.

CRTdrawing.GIF. 1897. J.J. Thomson’s Cathode Ray Tube. N.p., n.d. Web. 6 Oct. 2010. <http://www.chemteam.info/‌AtomicStructure/‌Disc-of-Electron-Images.html>.

Dchummer. Cathode Ray Tube. YouTube. N.p., 1 Oct. 2008. Web. 6 Oct. 2010. <http://www.youtube.com/‌watch?v=O9Goyscbazk>.

Ebbing, Darrell D., and Steven D. Gammon. General Chemistry Sixth Edition. Boston, Massachusetts: Houghton Mifflin, 1999. Print.

Masterton, William L., and Cecile N. Hurley. Chemistry Principles and Reactions Third Edition. Fort Worth, Texas: Saunders College, 1997. Print.

Shuttleworth, Martyn. “J.J. Thomson’s Cathode Ray Experiment.” Experiment Resources. N.p., n.d. Web. 6 Oct. 2010. <http://www.experiment-resources.com/‌frequently-asked-questions.html>.

Silberberg, Martin S. Chemistry the Molecular Nature of MAtter and Change. Boston, Massachusetts: McGraw Hill, 2003. Print.

thomson.jpg. Fall 2010. Reich-Chemistry. Tangient, n.d. Web. 6 Oct. 2010. <https://reich-chemistry.wikispaces.com/‌Fall.2008.MMA.Rowe.Timeline>.

Wilbraham, Anthony C., et al. Prentice Hall Chemistry. Boston, Massachusetts: Pearson Prentice Hall, 2008. Print.

Sunday, September 12, 2010

Eric's Salt Properties

As I was thinking about which household item I should choose, I immediately thought about salt (NaCl).  As with all matter, it has both physical and chemical properties.  I set out to explore what these were for salt.

All experiments in this project involving water use distilled water to insure accuracy.  Distilled water is free from ions, dissolved carbon, bacteria, and other contaminants.

Physical Property- A property that can be measured or observed without altering the composition of the substance.
The following are physical properties of sodium chloride.

1) Color- Sodium chloride appears clear to white.
2) Physical State- At room temperature, sodium chloride is a solid.

3) Crystallinity- Sodium chloride takes a cubic shape, with sharp edges.

4) Solubility- Sodium chloride is soluble in water forming a homogeneous mixture.
5) Electrical Conductivity- Sodium chloride has the ability to conduct electricity, as seen in the video. (This video was too long to upload directly onto this website.  Please click on the link below and it will take you to youtube.com)

Eric's Electricity Conductivity Video

Chemical Property- A property in which a substance has the ability to undergo a chemical change.
The following are chemical properties of sodium chloride.

1) Odorless- Sodium chloride has no odor.

2) Changing flame color- When sodium chloride is heated using a Bunsen burner, the sodium emits a yellow-orange light.  In the same way, sodium gas is used in street lights and emits a very bright, yellow-orange glow.

3) pH- Sodium chloride has a neutral pH (about 7).

Pool pH test strips used in the experiment.

They are very similar! (Distilled water on left. Distilled water containing NaCl on right.)
4) Flammability – Sodium chloride is nonflammable.  Sodium chloride does not burn or sustain a flame on its own.
Note that I am wearing safety goggles!

5) Taste- Sodium chloride has a very distinctive and desired taste.  Used in many foods, sodium chloride tastes salty.  In this experiment, I eat salt-coated pretzels.