I know on the pH scale that a 7 is good because it's freshwater. Is it bad if its lower (cont'd in details)

Question

or higher than 7. If so, why. Also what's calcium hardness? I have to find out for a science project which i have to compare the water quality of swamp and tap water. I have to think about ecology and potability and which is best for each use. If you guys have any help for that part too, I wouldn't mind accepting some help. Also, do you guys know any good environmental science websites which would help me greatly in this class? I would be grateful if I could get a website like that.

Answer 1

If you were to test pH of your tap water or other drinking waters, you would find that it probably ranges in value from around 5 - 9.

Calcium hardness is what causes the toilet bowl to turn chalky. Iron is what causes it to turn brown.

check out epa's website on http://www.epa.gov for ideas.

Answer 2

Water H2O is in balance with its ions H+ & OH-
the reaction is: H2O -> H(+) + )H(-)
the equilibrium constant is 10E-07 the log(10E-7) = -7
pH is the negative log of H(+) ion concentration so if you measured a 7 pH then that indicates there is no other (significant) sources of H(+) and OH(-) ions around. The EXACT pH depends on temperature and the equipment 'cuz you can never really get a totally undisturbed measurement - everything you use to take the pH will effect the result because of polarization effects among other things. Anyway CO2 is dissolved in water so a "natural" pH should be a little different since dissolved CO2 is acidic.
I am a diet pepsi freak, so pH 7 is bad! Labeling things "good" and "bad" is a moral judgement, not science. Which would you prefer to drink: Sea water with a pH of 4 (by adding HCl) or tap water with a pH of 7 (with both strychnine and anthrax in it) ?
Terms like "bad" and "good" are great for church and politics, way too simple for real life.
Calcium is dissolved in water (as the Ca(+2) ion). Especially ground water. It is one of the unusual compounds whose solubility drops as you heat the water up - which means water with a lot of Calcium in it will clog your hot water pipes as the "hardness" precipitates out of the water.
Water purity can be though of as based on four things: visual appearance (sediment, detritus, etc.), organic dissolved material (ethylene glycol (anti-freeze) is a poison, so is wood alcohol but they have little effect on pH), inorganic dissolved material (iron, lead (poison), mercury (ditto), uranium (radioactive) and its biological content (bacteria, viruses, plankton, amoeba, etc., etc.)
Tap water has been treated to remove a lot of stuff and is monitored to check for other things. Homeland Security has classified the details of what our water system does because of the possibility of terrorism.
As far as the help, I can't judge your age exactly but think you're old enough to spend the 5 or 10 minutes to find a couple of web sites that appeal to you. Your background and understanding will determine which site is best. You should consider a book rather than a web site. A least books should be less biased and more factual if they have been reviewed by the school board. BUt in environmental science thats often not the case. There's too many extremists and too much money involved to keep the politics out of it.

Answer 3

The pH of 7 means that the water is neutral, lower than 7 is acidic and higher than 7 is alkaline (basic). Drinking water can usually range between 5-8 on the pH scale. http://www.h2ou.com/h2wtrqual.htm#pH is a pretty good website for explaining the effects of pH in water. Also, calcium hardness is the concentration of calcium that is dissolved in the water. You could also check out the national science foundation's website, I'm sure they would have educational links.

Answer 4

If a solution has a pH of less than 7, it is acidic. Acid rain is bad because it can corrode metals. But lemon juice is acidic (has a pH level of less than 7) but you can't say its bad for your body. I think that if you have too much acid in your body, its bad, that's what I heard from a nurse. If the pH scale is higher than 7, then it is considered an alkaline solution or item. Batteries contain alkaline. To conclude, a lower pH or a pH doesn't really matter, it just depends what situation it is in, or how you use it. By the way, pH stands for potential Hydrogen, and it basically measures how hydrogen concentrated something is. The higher pH number the less concentrated the solution is with hydrogen ions. The lower the pH number, a solution is more hydrogen concentrated.

I suggest you visit these websites:

http://www.purchon.com/chemistry/ph.htm

http://staff.jccc.net/PDECELL/chemistry/phscale.html

Answer 5

1)An exact 7 is rare.So doesn't really matter.
2)Dunno