Questions for CM8001-AE 5
1.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.
During a hike, a simple method to purify water would to be boil it. The process of boiling destroys many of the harmful microbes present in water, making it safer for consumption. However, boiling of water does not remove chemical contamination within water and requires time to set-up.
Another method of water purification is to use chemical purifiers such as iodine. Iodine purifies water by killing bacteria in water, rendering it bacteriologically safe for consumption. Compared to the boiling of water, chemical purifiers are easy to use by simply being added to water. However, iodine should not be a long term solution for water purification as high concentration of iodine intake is toxic. Moreover, iodine does not add a good taste to water. In recent times, a safer form of purifying water was discovered in the form of ‘aquatabs’. These tablets contain tetraglycine hydroperiodide that kills bacteria while also reducing radioactive iodine within the human body.
A third method of purifying water is to use a filtration device. This method does not require the use of any chemicals. Although it does not remove as much microorganism, a good filtration system can be reused many times to generate relatively clean water for consumption. Recent technological advancement has also lead to the invention of ‘Lifestraws’. This filtration device not only removes 99.99% of waterborne bacteria but is also chemical free,portable and easy to use.
Municipal water supply purification relies on a combination of purifying techniques which includes some similar to the ones listed above. For example, chemicals such as fluorine and chlorine are used extensively in purifying tap water. The use of iodine closely relates to this method of purification. Also, similar filtration systems are used in municipal water. Towns and cities are known to filter water through large filtration systems to remove unwanted contaminants. The concept of a small filtration device closely relates to this by also filtering out unwanted substances. From the concepts listed above, boiling would be the one that is not commonly used in municipal water supply purification. Over the years, towns and cities have developed a multi-stepped process of water purification consisting of coagulation,sedimentation,filtration and disinfection. These processes have been able to supply high purity tap water without implementing a boiling stage.
2.Explain why desalination techniques, despite proven technological effectiveness, are not used more widely to produce potable drinking water.
There are two common desalination techniques, distillation and reverse osmosis. They are used to remove salts and other impurities present in sea water and also unfiltered water with the use of energy. This use of energy could be the reason why these techniques are not widely used to produce drinking water. However, if there were to be a cheaper alternative, I believe that the latter would be utilized to produce clean drinking water for the masses.
3.Water quality in a chemical engineering 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?
Lead can enter drinking water through corrosion of plumbing materials, especially where the water has high acidity or low mineral content that corrodes pipes and fixtures. This would probably be the major source of lead in the drinking water as it has the largest contact with the water supplied around the building. It is usually more serious with aging buildings because these buildings are more likely to have lead pipes, fixtures and solder. However, new buildings are also at risk because legally “lead-free” plumbing may contain up to eight percent lead.
The most common problem is with brass or chrome-plated brass faucets and fixtures with lead solder, from which significant amounts of lead can enter into the water, especially hot water. Corrosion is the dissolving or wearing away of metal caused by a chemical reaction between water and plumbing of the building. A number of factors are involved in the extent to which lead enters the water including the chemistry of the water (acidity and alkalinity), the amount of lead it comes into contact with, how long the water stays in the plumbing materials and the presence of protective scales or coatings inside the plumbing materials.
b. Do the research activities carried out in this chemistry building account for the elevated lead levels found in the drinking water? Explain.
Yes, research activities carried out in this chemistry building accounts for the elevated lead levels found in the drinking water.
There are proper chemical waste disposal containers placed in fume-hoods, mainly aqueous, chlorinated or non-chlorinated organic waste. These waste will be collected and disposed by special ways through transport to another facility, and never to the sink. Solid waste are transferred into an empty glove, tied up and thrown into the waste bin.
Laboratory manuals and Laboratory technicians do remind students to dispose waste into the respective containers. Furthermore, every student is required to complete and score with a high percentage score for a lab quiz at the start of each semester.
Upon leaving the laboratory to the washroom, students are required to remove gloves and hang their lab coats outside of the washroom, this ensures that student does not carry any unwanted chemical substance that might contaminate the water, even at very low concentration. Water fountains are not located in the laboratory, thus in order to use the water fountain, one has to leave the lab and by doing so, removes his/her gloves (preventing contamination).
These are some measures that chemistry department took to prevent lead from contaminating the potable water supply.
4. Some vitamins are water-soluble, whereas others are fat soluble. Would you expect either or both to be polar compounds. Explain.
The expression “Like Dissolves Like” will determine if the water-soluble or fat soluble vitamins are polar or nonpolar.
Water soluble vitamins are vitamins that are able to dissolves in water. Since the water soluble vitamins possess atoms to attract and to interact with the water molecules through hydrogen bonding, this shows that the vitamins is polar. Examples of water soluble vitamins are Vitamin B Vitamin C.
On the other hand, Fat soluble vitamins are vitamins that are able to interact with fatty solvent. Fat soluble vitamins contains more hydrocarbons (C and H atoms) than polar atom. Although it may contain polar atoms, the non-polar characteristic still outweighs the polar portion. This allows the fat soluble vitamins to interact with the non-polar chains in fatty solvent. Examples of fat soluble vitamins are Vitamin A, Vitamin D, Vitamin E and Vitamin K.