Friday, May 13, 2011

Test Review #1, a-u

a. an electron in the highest occupied energy level of an atom
valence electrons
b. shapes adjust so valence-electron pairs are as far as possible 
VSPER Theory
c. indicator changes colors
end point
d. attraction between polar molecules
dipole interaction
e. solution containing more solute than can theoretically dissolve at a given temperature
saturated solution
f.  a reaction in which a single compound is broken into simpler substances
g. the mass of a mole of any element or compound
molar mass
h. covalent bond in which only one pair of electrons is shared
single bond
i. covalent bonds occur between two of these
j. particle emitted when a nucleus transforms a proton into a neutron
k. rule explaining why atoms react so as to acquire the stable electron structure of a noble gas
octet rule
l. the percent by mass of each element in a compound
percent composition
m. this is conserved in every ordinary chemical reaction
n. acid with two ionizable protons
diprotic acid
o. the reactant that is not completely used up in a reaction
excess reactant
p. the reactant that determines the amount of product that can be formed in a reaction
limiting reagent
q. increases when a solute is added to a solvent to form a solution
boiling point
r. bonding formed by the attraction of valence electrons for metal ions
ionic bonding
s. the volume occupied by a mole of any gas at STP
22.4 L
t. occurs when an unstable nucleus divides into two nuclei of roughly equal mass
nuclear fission
u. a reaction in which oxygen in limited supply reacts with another substance often producing heat or light
chemical reaction

Monday, April 4, 2011

Nuclear Disaster

Site 1
How Nuclear Power Plants Work:
Site 2
(Site 2) In order to understand the effects, and benefits of nuclear plants, we have to know what goes on inside of them. The Core contains hundreds of Fuel Rods stacked with Uranium. To control the fission process, the rods known as "control rods," are raised and lowered to absorb neutrons. These are then surrounded by water known as the Moderator. The purpose of this water is to slow the neutrons so they are easily and effectively used. Then coolant is used to cool the reactor core. This water when heated is then used to produce steam and is recycled. This spins a turbine which produces electricity, then the steam is condensed back into cooler water.
History of Chernobyl:
(Site 3) Chernobyl was built in the marshlands of Northern Ukraine. All four reactors were built in the time range of 1977-1983. On April 25th, 1986, the fourth reactor was closed for maintenance to make sure it was producing enough energy to provide the city with power in case of an outage. When the tests were running, they also shut off a few of the safety systems. On April 26th, the power dropped and the reactor went out of control. Nobody outside of the plant knew, until two days later the operators of Forsmark, a Swedish plant, contacted Chernobyl because of high radiation levels measured near that plant. The Soviet Union denied any knowledge of a disaster, until April 28th when they said "one of the reactors had been damaged."
Chernobyl Reactor 4
Site 6
What went wrong at Chernobyl:
(Site 4) Much of the reason for the incident at Chernobyl was the ignorance of the workers to comply with the safety measures that were supposed to be taken. The Uranium fuel overheated and melted through the protective barriers. (Site 5) Also, the engineers that were staffing the nuclear reactor were specialists in electrical reactors, not nuclear. 

Chernobyl today
(Site 7)
What was done to remedy the situation:
(Site 3) The Soviets were trying to keep the disaster a secret but attempting to clean it up at the same time. At first, they tried to put the fires out by using water, sand, lead, and nitrogen. The fires burned for more than two weeks. Radiated soil and water were contained and the reactor was encased in cement. A new containment is set to be finished in 2013

What are some of the lasting effects today:
(Site 4) It is safe to visit the area today because the radioactive isotopes that still linger, are so small that they are tolerable for a short period of time. People have moved back to Chernobyl.
(Site 8) 28 of the firefighters at Chernobyl died within 3 months of the incident, and others died later from lasting effects. (Site 9) The radiation released was 400 times greater than that of Hiroshima. Over 300,000 people were resettled because of this catastrophe. Although radiation has increased, it has been reported that there has been more wildlife growth in this area (partially because of lack of human influence).

How does Chernobyl compare with Fukushima (Japan):
(Site 10) Chernobyl was the only radioactive disaster ever recorded at a level 7/10. The recent disaster in Japan has been upgraded to a level 5. Chernobyl was not prepared for the disaster that they faced, and were not aware of the consequences they would face. They did not begin evacuation until almost two days following the explosion, as opposed to Japan which began immediately. The Chernobyl disaster was caused by human carelessness, when the Japan incident was caused by natural disaster. (Site 11) Because graphite was used in Chernobyl, it caused a much bigger radiation "cloud," pushing the radiation higher into the atmosphere.

Should we be worried about the Japan incidents?:
(Site 11) Although radiation will travel across the United States, and most of the world at some point, it will be so small that it won't have any effect on the human body, or our everyday lives. (Site 13) Much of our products come from Japan such as seafood or clothing, but it is not believed that it will harm products from Japan. Scientists are monitoring the radioactive levels in case of a spike in radiation.


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