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lena213 lena213
wrote...
13 years ago
Hi everyone I am new to the forum! If I do this wrong please let me know. I need help with this particular discussion board. Water is ubiquitous and necessary for life on our planet. Describe the numerous unique properties of water and how it supports life. With specific applications to humans, what are the most common chemical contaminants of municipal water supplies in the country in which you reside? Why? What properties do these chemicals possess that allows them to be easy contaminants, and what risk do they pose to humans? Is access to clean drinking water a basic human right, do you think? Or is it merely a luxury? Why or why not?

2.) How do soaps work? Describe their chemical properties and give an example (including chemical formula) of a particular soap.

3.)Chlorine gas (Cl2; the 2 here is a subscript) is a gas at room temperature that can kill you if inhaled. When chlorine atoms bonds to other atoms, however, the resulting compounds have their own and completely different/unique properties and uses.

A) For example, table salt contains chlorine atoms, yet it doesn’t kill us if we consume it (well, at least in moderation!). Describe the chemical properties of table salt (NaCl). As you construct your response, try putting some table salt in a cup of water, and then try putting some into a cup of vegetable or cooking oil. Stir them both. What's the difference in terms of what you notice? How does this demonstrate the properties you explain?

B) By mixing chlorine gas with sodium hydroxide (NaOH), a.k.a. lye, you create sodium hypochlorite (NaOCl). NaOCl mixed with water is your common household bleach. Bleach is usually used as a disinfectant. Why? BE SPECIFIC HERE.


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bio_manbio_man
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13 years ago
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wrote...
Educator
13 years ago Edited: 13 years ago, bio_man
Describe the numerous unique properties of water and how it supports life.

1. Cohesion is the sticking together of similar molecules. Water is very cohesive. This allows water to be pulled along a pathway with relative ease. This helps trees pull water up to the top leaves.

2. Surface Tension and cohesion allows water to pull together and form droplets or form an interface between it and other surfaces. The measure of how hard it is to break this interface is its surface tension.
Water allows materials to rest upon it if the surface tension is not broken. Pollen, dust, water insects, and other biological materials are able to remain on the surface of the water because of this tension.

3. Adhesion the sticking of one substance to another along with cohesion produces capillary action which moves water up a thin tube like xylem in plants.

4. Imbibition: The process of soaking into a hydrophilic substance. Water being taken into a sponge, into a seed, into paper towels.

5. High Specific Heat: Specific heat of a substance is the heat needed (gained or lost) to change the temperature of 1g. of a substance 1degree Celsius. This high specific heat allows water to act as a heat sink. Water will retain its temperature after absorbing large amounts of heat, and retain its temperature after losing equally large amounts of heat. The Ocean acts as a tremendous heat sink to moderate the earth's temperature.

6. High Heat of Vaporization: Water must absorb a certain amount of additional heat to change from a liquid into a gas. This extra heat is called heat of vaporization. In humans, this value is 576 cal/g. This results in evaporative cooling of the surface.

7. Freezing and Expansion of Water: Water is most dense at 4 degrees C. At ) degrees C. it is 10% less dense. Ice floats because maximum Hydrogen bonding occurs at 0 degrees C.

8. Versatile Solvent: Water is a major solvent in nature. When water and another substance is mixed the resulting solution is called an aqueous solution. Cells are solutions made mostly of water.

With specific applications to humans, what are the most common chemical contaminants of municipal water supplies in the country in which you reside? Why?

I would say salts, such as NaCl. Contaminating fresh water with salt makes it undrinkable. Other contaminants are certain pathogens, such as bacteria. Bacteria can get into your intestines and make you very sick.

What properties do these chemicals possess that allows them to be easy contaminants, and what risk do they pose to humans?

Salts can easily dissociate in water. Our bodies were not designed to filter through large amounts of salt; its ingestion makes our blood hypertonic and this causes our blood cells to shrink in order to sustain the changes in salt concentation in our blood. Moreover, it affects our kidneys.

Is access to clean drinking water a basic human right, do you think? Or is it merely a luxury? Why or why not?

Absolutely. One thing that all living things have in common is the need to have water. All living things, whether it's a single-celled organism to something as large as a dinosaur need water to sustain life. Therefore, if life is a basic human right, water needs to be. Access to basic fresh clean water and to live in an environment free of disease and pollution should be a basic human right. Otherwise, the human race will end if no one gets access to fresh, clean water.
wrote...
Educator
13 years ago
3.)Chlorine gas (Cl2; the 2 here is a subscript) is a gas at room temperature that can kill you if inhaled. When chlorine atoms bonds to other atoms, however, the resulting compounds have their own and completely different/unique properties and uses.

A) For example, table salt contains chlorine atoms, yet it doesn’t kill us if we consume it (well, at least in moderation!). Describe the chemical properties of table salt (NaCl). As you construct your response, try putting some table salt in a cup of water, and then try putting some into a cup of vegetable or cooking oil. Stir them both. What's the difference in terms of what you notice? How does this demonstrate the properties you explain?

Dissolves in water to give Na+ + Cl- ions, both of which are mostly unreactive (spectator ions). Tastes salty, has a crystalline structure.

https://biology-forums.com/index.php?topic=3332.0

Putting salt in water makes it dissolve, because there are very strong electrostatic attraction between the sodium and chloride ions in a salt crystal, which react with water molecules, which are polar, so the ions are also strongly attracted to water molecules. This means that there is very little energy change when salt dissolves in water. As there are more ways of arranging the ions in solution than as a crystal entropy favours dissolving. Oil molecules are non-polar so there is little attraction for electrically-charged ions (Na+ and Cl-).

B) By mixing chlorine gas with sodium hydroxide (NaOH), a.k.a. lye, you create sodium hypochlorite (NaOCl). NaOCl mixed with water is your common household bleach. Bleach is usually used as a disinfectant. Why? BE SPECIFIC HERE.

Bleach can disrupt the cellular membrane of many pathogens because it acts like a detergent. It can also enter microbial cells and reacts with many cellular components (such as proteins), destroying them and killing the cell.
lena213 Author
wrote...
13 years ago
Thank you soooo much bio_man! This helps me out a lot! Chemistry can be really confusing for me! I am so glad to be part of this forum! It is nice to have a place where we can help each other out when needed. I really look forward to being able to help others out as well! Thanks a bunch for this Grinning Face
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