Tag Archives: AE5

Application Exercise 5

Q1. 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. 

Purify water by boiling, Use water purification tablet, Use small amount of household bleach.

Boiling kills many microorganisms that may make you sick, but requires time and will not remove chemical contamination. Boiling also requires time, fuel, and may release soot and CO to the environment.

Water purification tablet such as iodine tablet is easy and effective in twenty minutes, but it should not be used long-term. In addition, pregnant women and people with thyroid conditions should avoid purification with iodine. While iodine renders water bacteriologically safe, it doesn’t remove chemical contaminants. Many people dislike the taste of iodine-treated water.

Using a small amount of household bleach will kill some but not all microorganisms. Many people dislike the resulting taste.

 

Q2. Explain why desalination techniques, despite proven technological effectiveness, are not used more widely to produce potable drinking water.

The two most common desalination techniques are distillation and reverse osmosis. Both of these require large amount of energy to remove salts from seawater, and thus inherently are expensive. If a less expensive option is available, then the less expensive option is used.

 

Q3. 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?

The likely source of lead is from solder in the pipe joints or from lead pipes themselves.

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 should not contribute to lead in the drinking water, assuming that any lead compounds are disposed of using prescribed methods. Although many undergraduate chemistry experiments used to use lead, most now have been redesigned to avoid it and other toxic metal ions completely.

 

Q4. Some vitamins are water-soluble, whereas others are fat-soluble. Would you expect either or both to be polar compounds? Explain.

Fat-soluble is non-polar and water-soluble is polar compound. Fat-soluble contains long chain of non-polar hydrocarbons while water soluble compound contains polar chains.