Unit 10A: Objective 3 Activity

Vaughan Merrick 5/7/11
Block 8 Objective 3 Activity
Suspensions: Mixtures from which particles settle out upon standing. Suspensions are heterogeneous mixtures and can be removed by filtration because of the large size of the component particles. The average diameter of the component particles in a suspension is 100 nm.
Examples: Clay in water, sand in water and droplets of oil in air.

Colloids: Heterogeneous mixtures containing particles that are intermediate in size between those of suspensions and true solutions. The particles range in size from 1 to 100 nm. Colloids can appear in the states of gas, liquid or solid. The particles cannot be retained by filtration and do not settle out with time.
Examples: Glue, gelatin desserts, paint, aerosol sprays, and smoke.

Solutions: Homogenous mixtures that are completely uniform in composition. You are not able to tell the difference between the different compounds
Examples: Sugar in water, sodium chloride in water, carbon dioxide and oxygen in nitrogen (air).

How they differ: The component particles of a suspension and a colloid differ in size. The average size of a suspension particle is 100 nm, the size of colloid particle can be between 1 nm and 100 nm, and solution particles are about 1 nm. Also, colloids and suspensions are heterogeneous mixtures while solutions are homogenous. Lastly, using filtration, you could separate the particles in a suspension, but not in a colloid or a solution. The large size of suspensions allows this to occur.

Gas Law Internet Activity

Vaughan Merrick
Block 8
4/11/11

While viewing the relationship between the number of molecules in a closed chamber and the pressure, I observed that as the number of molecules increased, the pressure increased as well. This would make the relationship between these two variables linear. In both cases, whether I pumped in "heavy species" or "light species," the pressure increased on each pump of molecules. In "heavy species" from one pump to four pumps of molecules, I went from 82 molecules to 853 molecules with an average increase of about 193 molecules per pump. In this trial, the pressure increased from 0.45 atmospheres on the first pump to 4.40 atmospheres on the fourth pump, with an average increase of .99 atmospheres per pump. In the "light species," I went from 91 molecules on the first pump to 938 molecules on the fourth pump, with an average of 212 molecules increased per pump. As this occurred, the pressure increased from 0.47 atmospheres on the first pump to 4.35 atmospheres on the last pump, with an average increase of .97 atmospheres per pump. In this activity, as the number of molecules increased, the pressure increased as well.

Chemistry in Action Research Questions

Vaughan Merrick                                                                                                                    4/5/11

Block 8

What type of reaction is 1a?- Double Replacement

What type of reaction is 1b?- Corrosion

What do you think reaction 2 and 3 are? - Synthesis

1. What is hypoxia?

Hypoxia is a condition in which the level of dissolved oxygen is too low to sustain animal life.  This usually occurs when dissolved oxygen levels are below 2 milligrams per liter.

2. When does hypoxia reach its highest levels in Long Island Sound and in the Gulf of Mexico?

Hypoxia reaches its highest levels in the Long Island Sound and in the Gulf of Mexico when the colder water separates from the warmer water and stays along the bottom layers of the water.  When this occurs, the growth of phytoplankton and bacteria increase thus using up more oxygen and creating hypoxia in these bodies of water.

3. What causes hypoxia?

The causes of hypoxia include the build up of nutrients in the water and the stratification of the water.  When fresh water enters the ocean, the growth of phytoplankton occurs from the increase in nutrients that fresh water has.  Once these phytoplankton die, they fall to the ocean floor, where they are decomposed by bacteria.  These bacteria use the dissolved oxygen and do not recycle it, thus resulting in decreased dissolved oxygen levels.   In addition, due to changing temperatures and salinity, the cool, dense water separates from the warm water and stays near the surface. The bottom layer is then isolated and oxygen cannot normally resupply.  Thus dissolved oxygen is depleted and hypoxia occurs.

4. Research the sources of high levels of nitrate ions in water bodies.

The sources of high levels of nitrate ions in water bodies occur from fertilizer, decaying plants and manure from animals.  The nitrate from fertilizer makes its way into groundwater through irrigation and rain.  The groundwater can enter bodies of water through small rivers and deltas that feed directly into large bodies of water.  In addition, other human activities such as decaying plants and farming are increasing nitrate levels because of the manure that releases nitrate when it decomposes into the soil.  Our modern farming techniques that use fertilizers to grow grass for cows have a negative effects on water bodies because of the increased levels of nitrate.

5. What are “safe levels” of nitrate in drinking water and what are the effects on humans of drinking water with high levels of nitrate ion?

The “safe levels” of nitrate as reported by the U.S. Environmental Protection Agency are drinking water that contains less than 45 milligrams per liter of nitrate.  This figure can also be reported in the units parts per million.  The effect of high nitrate in drinking water is a condition called methemoglobinemia or blue baby syndrome.  This disease occurs mainly in infants under six months old and causes and increases in the amount of bacteria that convert nitrate (NO₃) into nitrite (NO₂).  Once this nitrite is absorbed into the bloodstream, it is changed into methemoglobin, which does not carry oxygen well.  This results in an oxygen deficiency to vital organs in your body. 

Url Citations:

http://www.gulfhypoxia.net/Overview/

http://www.ext.colostate.edu/pubs/crops/00517.html

http://toxics.usgs.gov/definitions/hypoxia.html  

Thermite Reaction

Vaughan Merrick                                                                                                  3/28/11

Block 8

Thermite Reaction

Balanced Equation:

Fe₂O₃(s) + 2Al(s) à Al₂O₃(s) +2Fe(aq)

I know that this chemical equation is balanced because Iron, Fe, has 2 on both sides, oxygen, O, has 3 on both sides and Aluminum, Al, has 2 on both sides of the equation. In this reaction, aluminum replaces iron to produce liquid iron and aluminum oxide.  

            The thermite reaction is useful in the molding together of steel sections and also cutting or welding rail tracks.  In order to fix gaps in steel rail tracks, this exothermic reaction can be used to mold the tracks together by having liquid iron melt down into the gap.  Second, in the cutting of rail tracks, the thermite reaction quickly cuts tracks that would otherwise need huge machinery to weld.  Thermite cannot only be used to mold steel tracks together, but also break them apart from each other.  The third use of the thermite reaction is in the disabling of artillery pieces.  This reaction allows militaries to disable an artillery piece without any noisy explosive charge.  This process makes artillery such as guns impossible to fire because the thermite reaction welds the gun shut. 

            Another useful single replacement reaction is the copper silver-nitrate reaction.  This reaction will not strike someone rich, but will produce beautiful silver flakes for a jeweler who is willing to spare a few dollars for pure silver.  In this reaction, copper replaces silver to produce solid silver and copper nitrate.  The balanced equation is:

Cu(s) + 2AgNO₃(aq) à 2Ag(s) + Cu(NO₃)₂ (aq)

Unit 7: Naming and Formula Writing Objectives 1 and 2 Activity a

Vaughan Merrick

Atoms- The smallest particle of an element that retains the properties of that element. The chemist John Dalton described the atom using a copper penny. If you were to grind the penny into dust, the little specks of dust would still retain the properties of copper. If you continued to split the specks of dust and found a particle that if split, it would no longer have the properties of copper, then you have found one single atom of copper.

Molecules- The smallest electrically neutral unit of a substance that still has the properties of the substance. Molecules are made up of two or more atoms that act as one unit.

Formula units- This represents an ionic compound and it is the lowest whole-number ratio of ions in the compound. For example, in sodium-chloride, the lowest whole-number ratio of ions is 1:1, so the formula unit is NaCl.

Ionic compounds-These are compounds composed of cations and anions. They are usually composed of a nonmetal and metal anions. These compounds have high melting points usually above 300°C. At room temperature, these compounds exist in the solid state. In addition, its representative unit is the formula unit.

Molecular compounds-These are simply compounds composed of molecules. They must be electrically neutral and be combinations of molecules. These compounds have low melting and boiling points and at room temperature, can exist as liquids, gases or solids. Most of the molecules in molecular compounds are composed of the atoms of two or more nonmetals. This compounds representative unit is the molecule.

Bonding Exit Mission-Vaughan Merrick

Vaughan Merrick                                                                                                    2/24/11

Block 8                                                                                    Exit Mission for Bonding Unit

5 Reasons Why We Should Learn About Bonding

We need to learn about bonding because it brings together essential elements like Oxygen and Hydrogen to form compounds that humans could not exist without.  Without bonding, we would not be able to obtain the necessary fluids we need to survive. It brings together elements naturally that would otherwise not be able to stick together.   Bonding helps create the fossil fuels that we rely on to live out daily life.  We need these rich natural resources to stay warm and for transportation needs.  Bonding also helps to give atoms full octets on the outer layer of electrons.  Without bonding and molecules being able to give electrons to one another, atoms would not be happy without full sets of eight electrons in their outer shells.   We should also learn about bonding because we can then learn about the electronegativity difference of the elements bonded and determine if the molecule is ionic or covalent.  Bonding helps lead us to other important physical characteristics in chemistry.  Lastly, bonding helps us understand how atoms come in contact with one another.   For example, atoms will more often then not bond with other atoms that are missing the amount of electrons that they have to give.  Bonding needs to be learned about to show how elements work together in chemistry.