Tuesday, May 17, 2011

Chemistry Review Questions

3.         Which two forms of compounds (ionic, covalent, metallic) can conduct electricity? Under what conditions can they conduct electricity and why?

Ionic and metallic bonds can conduct electricity.

Ionic
Ionic compounds can conduct electricity when in a molten state or if dissolved. They can conduct electricity in these states because the electrons can move throughout the molten compound or in the solution formed. They cannot conduct when solid unless they are under the influence of an electric field.

Metallic
Metallic compounds can conduct electricity only when they are molten or dissolved in a solution. When molten or dissolved the compounds’ electrons are free to move around and are able to conduct in these states. Electricity is able then to pass through the free electrons in the molten or dissolved substance.

31. CH.9 Test Review: Change in pH, how to find the grams needed to increase the pH of a solution.  (Thought this problem was a little hard at first, but once explained it can be very simple.)
9) How many grams of NaOH would be needed to make the pH of a solution increase from 10.000 to 12.000 using 500.0mL of the solution.

Information: 

pH1 10.000 -> pOH 4.000
pH2 12.000 -> pOH 2.000
V .500 L

Solve for molarity of OH-:
pOH -> M OH+ (10^-pOH)

pOH1 = 1.000x10^-4 M OH-
pOH2 = 1.000x10^-2 M OH-

Solve for the moles of OH- of each:
mol = MV

mol OH1- = 5x10^-5
mol OH2- = .00500

Find the change of the # of moles:

(mol OH1-) - (mol OH2-) = .00495 mol OH-

Moles of OH- in NaOH is 1 mol OH-

.00495 mol OH- x 40g NaOH/1 mol OH- = 
.198g NaOH



Thursday, April 7, 2011

Chernobyl and Japan

Chernobyl

            Chernobyl was a nuclear power plant located in the Ukraine. The disaster took place on April 26, 1986 at 1:23 am. The problem in the reactor was caused by a flawed reactor design with inadequately trained personnel. The inexperienced personnel took the power down and then tried to power it back up quickly to check whether a 40 second power gap in the cooling system could be bridged. The first night of the incident two plant workers died, another 28 died in the few weeks after the incident. 134 people were diagnosed with ARS or acute radiation syndrome. The accident at Chernobyl destroyed the Chernobyl 4 reactor.  Large areas of Belarus, Ukraine, and Russia and beyond were contaminated in varying degrees.

20 Years later

            Radiation from the disaster spread to parts of the western Soviet Union, Eastern Europe, Western Europe, Northern Europe, and eastern North America. Large areas in Ukraine, Belarus, and Russia were badly contaminated, resulting in the evacuation and resettlement of over 336,000 people. According to official post-Soviet data, about 60% of the radioactive fallout landed in Belarus. In some of those areas that were contaminated people were affected greatly. Children were born with several deformities and/or cancerous tumors.
image.jpg






25 Years later

            The area is currently fenced in an area known as the Exclusion Zone. Remnants, still radioactive, are still inside. The enclosure is a 24 story concrete and steel encasement, that was quickly built after the event, but is currently structurally unsound and threatens to collapse. If it were to fall, enough radiation would be released to cause a second disaster of similar consequences. A new structure has been planned to be built around the current enclosure to ensure radiation does not escape, but the price for this is estimated to be about 2 billion dollars.

Differences between Chernobyl and Japan

·        Chernobyl was a 3200 MV Reactor and the three reactors in Japan were 500 MV

·        Chernobyl exploded while it was working at peak capacity and the reactors in Japan were turned off successfully after the first tremors of the earthquake

·        Chernobyl was a Soviet RBMK-1000 reactor and the Japanese reactors were Boiling Water Reactors

·        Chernobyl was a new design undergoing tests while the reactors in Japan were proven to work well



Brief Summary of How Nuclear Reactor Works

            “The core of a nuclear reactor contains both water and fuel rods made of zirconium and pellets of nuclear fuel, such as uranium, that set off a controlled nuclear reaction. The reaction, heats the water, creating 550-degree Fahrenheit steam, which powers a turbine, generating electricity.”

Japan

            In some articles it describes the danger as being small. Only a small amount of radiation is currently being released from the damaged reactors in Japan. Once the reactors cool down, they can determine whether or not the cores are undamaged and whether or not people should be really worried.

latest news Japan nuclear reactors 300x207 Japans workers struggle to bring power back to Fukushima reactor
Works Cited

Casselman, Ben, and Rebecca Smith. “How Nuclear Reactors Work... And the Dangers When They Don’t.” The Wall Street Journal. N.p., 15 Mar. 2011. Web. 7 Apr. 2011. <http://online.wsj.com/‌article/‌SB10001424052748704893604576200982857244782.html>.
“Chernobyl Accident.” World Nuclear Association. N.p., Mar. 2011. Web. 7 Apr. 2011. <http://www.world-nuclear.org/‌info/‌chernobyl/‌inf07.html>.
“Chernobyl: 25 Years After The Nuclear Disaster (PHOTOS).” HuffPost Green. N.p., 7 Apr. 2011. Web. 7 Apr. 2011. <http://www.huffingtonpost.com/‌2011/‌02/‌02/‌chernobyl-25-years-after-_n_816902.html#s233577>.
Marquand, Robert. “Japan’s nuclear crisis and Chernobyl: key differences.” The Cristian Science Monitor. N.p., n.d. Web. 7 Apr. 2011. <http://www.csmonitor.com/‌World/‌Global-News/‌2011/‌0313/‌Japan-s-nuclear-crisis-and-Chernobyl-key-differences>.
Waldoks, Ehud Zion. “’Comparison between Chernobyl, Japan out of place.’” The Jerusalem Post. N.p., 15 Mar. 2011. Web. 7 Apr. 2011. <http://www.jpost.com/‌Sci-Tech/‌Article.aspx?id=212169>.
Pictures/Video:

Saturday, January 22, 2011

CREATIVE CHEMISTRY

                         Edible Covalent Compounds


Name
Molecular Formula
Empirical Formula
Common Food
Water
H2O
H2O
Water
Sucrose
C12H22O11
C12H22O11
Sugar
Carbon dioxide
CO2
CO2
Found in sodas
Acetic Acid
CH3COOH
CH2O
Found in vinegar
Ethanol
C2H5OH
C2H6O
Drinking alcohol



                           Covalent Compound Haiku



Covalent compounds
Atoms sharing electrons
Balance of forces





Sunday, December 12, 2010

My 10 Ions for my group (Paxton and I)

Centrum A to Zinc
calcium carbonate         CaCO3
magnesium oxide          MgO
manganese sulfate         MnSO4
potassium iodide           KI
zinc oxide                     ZnO



Best Life Buttery Spread
sodium nitrate               NaNO3
sodium hypochlorite      NaOCl
calcium hypochlorite     Ca(ClO)2
lead (VI) chromate       Pb(CO3)2
mercury (II) chloride     HgCl2

Friday, November 12, 2010

Exam Review 1. ( r - gg )

r. Distillation

t. Representative Elements

u. Electrons

v. Nucleus

w. Thomson

x. Atomic Number

y. Atom

z. Isotopes

aa. Pauli Exclusion Principle

bb. Chemical Reaction

cc. Atomic Mass

dd. Heisenberg Uncertainty Principle

ee. Periodic Trends

ff. Mixture

gg. N

Sunday, October 3, 2010

The Cathode Ray


Cutaway rendering of a color CRT:
1. Three Electron guns (for red, green, and blue phosphor dots)
2. Electron beams
3. Focusing coils
4. Deflection coils
5. Anode connection
6. Mask for separating beams for red, green, and blue part of displayed image
7. Phosphor layer with red, green, and blue zones
8. Close-up of the phosphor-coated inner side of the screen
The cathode ray tube is a vacuum tube containing a source of electrons, like an electron gun, it also has a fluorescent screen, with internal or external means to accelerate and deflect the electron beam. The cathode ray tube uses an evacuated glass envelope which is large, deep, heavy, and relatively fragile. The cathode ray is a stream of electrons in a vacuumed tube. An evacuated glass tube, equipped with at least two metal electrodes has a voltage applied to it. The voltage is a cathode or negative electrode and an anode or positive electrode. The cathode ray was first observed in 1869 by Johann Hittorf, a German physicist, but was named in 1876 by Eugene Goldstein kathodenstrahlen, or cathode rays. Electrons were first discovered using the cathode ray by J.J. Thomson in 1987. Thomas showed that the rays also had negatively charge particles, which were the electrons. Thomson found that the rays could be deflected by an energetic field. He was able to measure the particle's mass by comparing the deflection of a beam of cathode rays by electrical and magnetic fields. He discovered that they were 2000 times lighter than a hydrogen atom. He concluded that the rays had negatively charged particles.
One of the important things about the discovery of the electron was the electron microscope. It was invented in 1928 by Ernst Ruska. The electron microscope uses a stream of electrons to magnify something. Electrons have small wavelengths so they can be used to magnify objects that are too small to be resolved by light. Ruska used a strong magnetic field in order to focus the electrons into an image in a stream.

For information on how the cathode ray tube is go to: http://www.youtube.com/watch?v=XU8nMKkzbT8

Friday, September 10, 2010

Chemical Changes

Chemical Changes:


The first experiment was burning the CD to test its flamability. I used matches to try and burn the CD. The Cd did not catch on fire, it simply darkened and melted a little.

Burned CD:
















The second experiment I placed the CD in water to see how it would react, But like most plastics nothing happened. The CD was unchanged and did not react with the water.

CD in water:















For the third experiment I placed the CD in orange juice to see how it would react to the citrus acid. There weree no real changes to the CD. The only thing that happened to the CD is that it became sticky.

CD in orange juice:
















For my fourth experiment I placed the CD in a bowl of bleach. The CD reacted very little to the bleach. The sharpie mark on it disappeared and the top color became slightly lighter. The colors of the paint on the CD only became lighter, but other than that it remained unchanged.

CD after bleach:















For my fifth and final experiment I placed a CD in the microwave to see how it would react to the radiation.
The CD sparked and became cracked.

video