You are considering becoming an Analytical Chemist! Conduct some research and briefly discuss the following questions.
- What are the educational requirements and credentials needed to become an analytical chemist?
- What are some typical job responsibilities of an analytical chemist?
- What type of work environment can an analytical chemist expect to experience on a day-today basis?
You apply for an opening at Kaplan Industries – one of the premier pharmaceutical corporations in the country and are granted an interview. For the written part of the interview process, you are asked to determine the strength of several commercial antacids provided by the Food and Drug Administration (FDA). You are given five antacids to be tested with a back- titration that works as follows:
- First, each antacid tablet is mixed with 40 mL of 0.1 M HCl—this acidic solution is the same stuff that is in stomach acid, and one antacid pill is nowhere near enough to neutralize all 40 mL of the acid.
- So, to see how much extra help each antacid pill needs to neutralize 40 mL of 0.1 M HCL, you add 0.05 M NaOH drop-by-drop to back-titrate the solution until the pH is neutral.
- What this means is that, the stronger the antacid tablet, the less NaOH it will take to help bring the acid to neutral. (In other words, the stronger antacid tablets counteract more of the original HCl, leaving the solution closer to neutral before the NaOH is added.)
Here are your results:
Maalox Tums Mylanta CVS brand Rennies
Mass of one dose antacid 20.0 g 21.0 g 18.0 g 18.3 g 17.5 g
mL NaOH used in back-titration 24.1 mL 22.4mL 20.0 mL 19.9 mL 24.4 mL
Based on these results, answer the following questions:
1. Which is the strongest antacid, on a single-dose basis? Which is the weakest? Explain and show your calculations.
2. Which are the strongest and weakest, on a by-weight (mass) basis?
3. When people do back titrations, they usually watch the solution for a color change when the solution becomes neutral. What might you have used in the above experiment to get this color change to happen in the solution? At what pH would the solution have been neutral?
4. If you had walked into the lab, only to discover that you only had 0.1 M sulfuric acid available to run your tests, how might this have affected your calculations? Why?
5. In most of the antacids you tested, the active ingredient is aluminum hydroxide. Here is an unbalanced reaction that shows how this chemical neutralizes HCl (the main ingredient in stomach acid). Provide a balanced version of this equation:
6. AI(OH)3 + HCI -> AICI3 +H20
7. The FDA requires that all of its reports be super-brief—short enough so that they can be sent via text message to all of its lab sites across the country. As you probably know, the word limit for text messages is very small, so your goal here is to describe precisely what you did to test the antacids in fewer than 150 words. In this brief report, you should provide the FDA with the major findings from your tests and let them know generally how you performed your tests.
This material may consist of step-by-step explanations on how to solve a problem or examples of proper writing, including the use of citations, references, bibliographies, and formatting. This material is made available for the sole purpose of studying and learning - misuse is strictly forbidden.Analytical chemistry is the area of analytical science which is responsible for characterizing composition of matter both qualitatively as well as quantitatively. However its craft is not only the analysis on routine samples for ensuring the quality of finished products on chemical phenomena but improving existing methods and developing novel, safe and cheaper methods of analysis as well as extending exiting methods for new samples in other fileds of chemical science. Analytical chemists typically operate at the extreme edges of analysis, extending and improving the ability of all chemists to make meaningful measurements on smaller samples, on more complex samples, on shorter time scales, and on species present at lower concentraions. An analytical chemist during an analysis may adopt following...