- How can you purify your water when you are hiking? Name two or three possibilities.Compare these methods in terms of cost and effectiveness. Are any of these methods similar to those used to purify municipal water supplies? Explain.
One of the method used is purification with iodine, however people with thyroid issues and expecting ladies should not use this method due to the adverse health effects on this group of people. This method would remove bacteria in the water effectively but results in a taste in the water.
An alternative method is to boil the water, this process would kill most of the micro-organism that is harmful but requires time and does not remove chemical contaminants. A drawback of this method is the release of soot and carbon dioxide to the environment.
A filtering device can also be used. Filtration is chemical free and is more effective in removing microorganism not purified by boiling or iodine treatment. Compared to the two other methods, filtration is more expensive but reusable method and can be done in a relatively short time.
Compared to the methods used to purify municipal water supplies, the methods listed above are relatively simplified, for instance, water purified for municipal use go through rigorous processes which includes filtration, sterilisation, fluoridation etc. before it is released for public consumption.
2. Explain why desalination techniques, despite proven technological effectiveness, are not used more widely to produce potable drinking water.
Desalination is not widely used as the method uses a lot of energy. Desalination plants around the world consume more than 200 million kilowatt-hours each day, with energy costs an estimated 55 percent of plants’ total operation and maintenance costs. It takes most reverse osmosis plants about three to 10 kilowatt-hours of energy to produce one cubic meter of freshwater from seawater. Therefore, while desalination is an effective method to produce potable water, it is not widely used.
3. Water quality in a chemistry building on campus was continuously monitored because testing indicated water from drinking fountains in the building had dissolved lead levels above those established by NEA.
a.What is the likely major source of the lead in the drinking water?
Solder found in the pipe joints or from lead pipe are likely the major source.
b. Do the research activities carried out in this chemistry building account for the elevated lead levels found in the drinking water? Explain.
Research activities are unlikely to cause the elevated lead levels as most experiment would avoid using Lead (a toxic metal). Assuming that if any experiment involve the use of Lead, it is assumed that such toxic substance are not dumped into the drain, but handled with caution.
4. Some vitamins are water-soluble, whereas others are fat-soluble.Would you expect either or both to be polar molecules? Explain.
Only water-soluble vitamins would be expected to be polar molecules. Though a fat-soluble vitamin may contain polar bonds in portion of the molecule, the bulk of the molecule will be non-polar, this means the molecule will be non-polar since the dominant interaction is non-polar. Polar covalent bonds attract to water through hydrogen bonding and may allow the molecules to dissolve in water, while nonpolar covalent bonds favor interactions with the nonpolar chains in lipids.