Objective 3 Activity: Solution, Suspension, and Colloid

Solution: a homogeneous mixture. Solutions are the most important of the three to chemistry.
Vinegar is an example of a solution.

Suspension: a mixture from which some of the particles settle out slowly upon standing; a heterogeneous mixture
An example of a suspension is clay and water. The suspended particles can be easily removed through filtration.

Colloid: a liquid mixture containing particles that are intermediate in size between those of a suspension and a true solution; these particles are evenly distributed throughout the liquid and do not settle out with time
One example of a colloid is gelatin.


Suspension-->Colloid-->Solution
(these terms are a progression of how thoroughly mixed a mixture is)

gas law activity

Although more molecules were released with each pump of the "light species", the pressure for both increased at about the same rate. Therefore, I can observe that the number of molecules has a direct effect on the pressure and whether the molecules are of the "heavy species" or the "light species" is irrelevant. I also noticed that the more molecules there were, the faster they moved.

Chemistry in Action

QUESTION 1:
For the dissolved oxygen reactions:
What type of reaction is 1a? double replacement
What type of reaction is 1b? synthesis
What do you think reaction 2 and 3 are? triple replacement
QUESTION 2:
a. What is hypoxia?
Hypoxia is when the oxygen concentration in water is below the levels necessary for sustainable life.
b. When does hypoxia reach its highest levels in Long Island Sound and in the Gulf of Mexico?
Hypoxia is at its highest in the Long Island Sound from mid-July to September. It is the same for the Gulf of Mexico.
c. What are the causes of hypoxia?
One cause of hypoxia is that fresh water and salt water interact, particularly at the Gulf of Mexico. Another is an increase in nitrogen and phosphorus use by humans.
d. Research the sources of high levels of nitrate ion in water bodies.
Nitrates get into water because of the increase in human use. People use nitrates in their fertilizer, and there is runoff, which ends up in the ocean. Human and animal waste can also contribute to the nitrate levels in water.
e. 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?
According to the EPA, the Maximum Contaminant Level of nitrate is 10 ppm. It can cause blood disorders in infants, called “blue baby syndrome.” If pregnant women drink it, it can cause defects in their babies. It can also increase the risk of cancer.
http://toxics.usgs.gov/definitions/hypoxia.html
http://cfpub.epa.gov/eroe/index.cfm?fuseaction=detail.viewInd&lv=list.listByNewest&r=231335&subtop=274
http://www.bfhd.wa.gov/info/nitrate-nitrite.php http://www.dnr.state.wi.us/org/water/dwg/nitrate.htm

Single Replacement Reactions

In a thermite reaction, aluminum powder and iron (III) oxide react to form “a quality molten steel.” It is important because it can be used to precision-weld two pieces of metal, particularly in railroad tracks. It was developed by Hans Goldschmidt in 1893, and was used to make the tracks more comfortable, safer, and faster.

The reaction is written as: Fe₂O₃ + 2 Al → Al₂O₃ + 2 Fe
Aluminum powder and iron oxide react to produce aluminum oxide and iron.

Another useful single replacement reaction is
Cu(s) + 2AgNO₃(aq) → 2 Ag(s) + Cu(NO₃)₂(aq)
We did this experiment earlier in the year.
Copper and silver nitrate react to form silver and copper nitrate.

http://www.chymist.com/Thermite%20reaction.pdf