Saturday, September 4, 2010

Blog Posting-Chapter 2 (Chemical and Physical Properties)

For my blog posting I decided to research the chemical and physical properties of an original style Alka Seltzer Tablet. Alka Seltzer is a medicinal antacid in tablet form composed of aspirin, sodium bicarbonate, and citric acid that is manufactured by Bayer Health Care.

one alka seltzer tablet

Physical Properties:

1. White in color

2. Non lustrous
-There is no shine or sparkle evident when visually examining the tablet

3. Brittle
-The tablet does not give or bend before fracturing when subjected to stress
-easy to split or break with relatively little force

4. Mass(of one tablet)=3.808 grams
-I calculated the mass of a tablet of Alka seltzer by adding together the masses of all the active and inactive ingredients listed on the manufacturers website. The ingredients were 325mg Aspirin, 1916 mg sodium bicarbonate, 1000mg citric acid, and 567 mg sodium. The sum of all the ingredients= 1916 mg+325 mg+1000 mg+567 mg=3,808 mg= 3.808 grams

5. The tablet is a solid at room temperature

Chemical Properties:

1. effervescent 
-dissolves quickly in water, normally this would be called solubility and would be a physical property by in the case of alka seltzer it is a chemical property due to the fact that after the chemical reaction with water a different substance is produced.
-the reactants in this chemical reaction are water and the chemicals making up alka seltzer (aspirin, citric acid, and sodium bicarbonate). after the reaction takes place and the alka seltzer is dissolved in water it becomes Sodium Acetylsalicylate, Sodium Citrate, Carbon Dioxide, and Sodium Hydrogen Carbonate (the products). Because the products and reactants are different substances the reaction taking place is a chemical reaction and the ability of the alka seltzer to undergo that reaction is a chemical property of the alka seltzer.

2. Neutralizes acidity
-If alka seltzer is added to an acidic substance such as vinegar there will be a violent reaction that will slowly die down and the vinegar's acidic level will be neutralized
-the reaction between alka seltzer and vinegar is similar to the reation that occurs in your stomach when alka seltzer is ingested and the neutralization of acid is how alka seltzer relives acidic indigestion.
-to prove that acidity is nuetralized I first dropped alka seltzer into vinegar and let the reaction take place. Then I added Baking soda to the vinegar. The fact that the Baking soda failed to react proves that the acetic acid present in the vinegar has been neutralized. if the acetic acid was still present there would be a violent reaction similar to the one seen in the control (which was just baking soda and vinegar without any alka seltzer).

3. non flammable (tested)
-when exposed to an open flame, the alka seltzer tablet show no tendency to burn or ignite, proving that the alka sektzer does not have flammable tendencies

4. Tablet bubbles and Fizzes when heated
-when exposed to an open flame the tablet takes on a brownish color and then begins to bubble and fizz, similar to how it bubbles when it is put in water. Even exposure to extreme heat, however, has minimal effect on the effervescent qualities of the tablet. The tablet still has almost the same reaction with water.

5.Extremely sour and bitter taste when not dissolved in water (tested)

Works Cited:

Official Alka Seltzer Website

Alka Seltzer Original style product page


  1. very well done. You supported your claims well with both experiments and research. You were also creative with your choice of properties and how you went about proving them.

  2. when the little circle thing dissolves in water it is definitely a chemical change. Good posting sahil, although you might want to seek out a better quality video taker. anyway 1 comment down, 2 more to go!

  3. I am impressed, very well done. Just a few small things:
    1. I want to congratulate your use of sig figs and dimensional analysis on the physical property of mass. Next time, include whether the property was intensive or extensive, though.
    2. Now I'm not sure myself on the mechanisms and trivialities of room temperature, but if you dropped alka seltzer in water at room temp., would it still be a solid?
    3. Your experiment for neutralizing acidity deserves an applause, so imagine me clapping.
    4. Your third and fourth chemical properties were completely contradicting. One said didn't, the other said did, for the same thing! Look at that again.
    I can conclusively say that you did a fantastic job. Well done!

  4. well on the third and fourth properties, in the third I said that the tablet did not catch fire and in the fourth I said that even though it did not catch fire it still slightly reacted with the heat. Basically what I am saying is that it is not flammable but that it does still react with heat