Question 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.

There are these three ways of purifying water when you are hiking, firstly, by boiling water rapidly for 10 minutes; secondly, by filtering the water; and lastly, by using iodine tablets.  

Filtering is fast, allowing you to drink the water immediately once it’s clean.  Filters have also become much smaller, more effective and less expensive in the last 10 years.    Boiling requires more work than filtering, but does not need any extra gear.  Iodine tablets are extremely effective in killing viruses but take 30 minutes to be totally effective.

The common methods used to purify municipal water supplies are reverse osmosis, distillation, ultraviolet, and ozone produce purified water.  Other methods used are filtration methods such as adsorption, carbon, activated carbon, kinetic degradation fluxion, and particulate filtration.

Filtration is similar to reverse osmosis, which forces water through a semi-permeable membrane that filters out salt, lead, manganese, iron and calcium, as well as certain chemicals.  Boiling is similar to distillation, that boils water to collect the steam, leaving behind the pollutants.  

Question 2:

Explain why desalination techniques, despite proven technological effectiveness, are not used more widely to produce potable drinking water?

Despite proven technological effectiveness, desalination techniques are not used more widely to produce potable drinking water due to the following reasons. Firstly, the desalination of water is expensive. This is because the salt dissolves in water very easily, large amount of energy is required in order to separate the salt and water. Hence the cost for desalination is high. Besides, the residue is brine which must be disposed carefully in order to avoid environmental pollution. Hence a cost is needed for disposal of brine.

Question 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 be used as an ingredient in making pipes. Hence, lead could enter the drinking water through the plumbing system in the chemical engineering building. This is due the process of corrosion, where the corrosive water dissolves lead from lead pipes when it is in contact with the plumbing. The corrosivity of water depends on several factors such as pH, temperature and softness of water.  

b. Do the research activities carried out in this chemistry building account for the elevated lead levels found in the drinking water? Explain.

The professors and students definitely understand the harmful effects of lead on the environment and human health. If there are chemistry experiments involving the use of lead, they would manage it appropriately. For example, they would not dump the lead compound into the drain. Alternatively, they might replace the lead with other substances to conduct the experiments. Therefore, the research activities carried out in this chemistry building should not account for the elevated lead levels found in the drinking water.   

Question 4:

Some vitamins are water-soluble, whereas others are fat-soluble. Would you expect either or both to be polar compounds? Explain.

Vitamins must be soluble in either water or fat depending on their molecular structures in order for the human body to absorb them into the body system. Vitamins which are soluble in water should possess many polar groups due to the inherently polar nature of water. Vitamins which are soluble in fat are predominantly non-polar which explains its solubility in non-polar solvents like the fatty tissues in the body. Hence I would expect only water-soluble vitamins to be polar compounds.