Assignment: Alka Seltzer
Instructions:
Read the article on Alka Seltzer (What would happen if you mixed sour salt with baking soda and added
some water?) and answer the following questions. Some questions require a little extra research. Place
answers on the answer sheet at the end of this document for submission.
1. Sour salt is the common name for:
a)
b)
c)
d)
e)
sodium bicarbonate
sodium chloride
acetylsalicylic acid (ASA)
sodium citrate
citric acid
2. Baking soda is the common name for:
a)
b)
c)
d)
e)
sodium bicarbonate
sodium hydrogen carbonate
acetylsalicylic acid (ASA)
sodium citrate
both a and b
3. What is the chemical formula of sour salt?
a)
b)
c)
d)
e)
C6H12O6
CH2O
C2H6O
C6H8O7
CH4O
4. How many “acidic” H atoms are there in one molecule of sour salt?
a)
b)
c)
d)
e)
1
2
3
4
5
5. What is the chemical formula of baking soda?
a)
b)
c)
d)
e)
Na2CO3
NaCO3
NaH2CO3
NaHCO3
Na2HCO3
6. What type of reaction(s) would occur between an acid and baking soda?
a)
b)
c)
d)
e)
synthesis and combustion
combustion and decomposition
single displacement and synthesis
decomposition and single displacement
double displacement and decomposition
7. What are the products of the reaction between citric acid and baking soda?
a)
b)
c)
d)
e)
sodium citrate + water
sodium + water + carbon dioxide
sodium citrate + carbonic acid
sodium chloride + carbon dioxide
sodium citrate + water + carbon dioxide
8. What is the chemical formula for aspirin?
a)
b)
c)
d)
e)
C9H8O4
C12H22O11
CH2O
C6H8O7
C7H6O3
9. How many “acidic” H atoms are there in one molecule of aspirin?
a)
b)
c)
d)
e)
1
2
3
4
5
10. What are the products of the reaction between aspirin and baking soda?
a)
b)
c)
d)
e)
sodium bicarbonate + acetylsalicylic acid
sodium acetylsalicylate + water + carbon dioxide
sodium chloride + water
sodium acetylsalicylate + carbon dioxide
sodium + water + carbon dioxide
11. What are the ingredients in Alka Seltzer?
a)
b)
c)
d)
e)
aspirin
baking soda
citric acid
both b and c
a, b, and c
12. What is heartburn?
a)
b)
c)
d)
e)
the feeling you get when you see someone you’re attracted to
a burning sensation felt in the stomach due to stomach ulcers
a burning sensation felt in the mid esophagus region due to exposure to stomach acid
a headache caused by doing too much homework
none of the above
13. What is the purpose of taking Alka Seltzer?
a)
b)
c)
d)
e)
it is used as a sodium supplement
it is used to neutralize excess stomach acid and treat an accompanying headache
it is used to enhance your intelligence
it is used to wash dishes
it is used to satisfy your need to see a cool chemical reaction when you add it to water
14. What is the chemical formula for sodium citrate?
a)
b)
c)
d)
e)
Na2C4H4O6
NaCN
Na2CO3
NaClO
Na3C6H5O7
15. The article mentions that sodium citrate is an effective antacid. Why is this so?
a)
b)
c)
d)
sodium ions can capture H+ ions from stomach acid which acts to neutralize the acid
citrate ions can capture H+ ions from stomach acid which acts to neutralize the acid
both a and b
none of the above
16. Why is citric acid added as an ingredient for Alka Seltzer?
a) to help get the “fizz fizz” to boost sales
b) to form sodium citrate which acts as an effective antacid
c) both a and b
17. What is the difference between the chemical makeup of a Ballistic Bomb and Alka Seltzer?
a) the Ballistic Bomb contains premade, compressed CO2 gas which releases when it dissolves
b) Alka Seltzer contains various scent chemicals
c) the Ballistic Bomb does not contain any ASA
18. Why do they call it Alka Seltzer?
a) it just sounds cool
b) Alka Seltzer is the name of the person who invented it
c) alka refers to alkaline (base) and seltzer refers to carbonated water (a plop plop fizz fizz antacid!)
Answer Sheet: Alka Seltzer
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Name: ______________________ /18
What would happen if you mixed sour salt with baking soda and
added some water?
You would get some pretty vigorous bubbling as the carbon dioxide generated escaped from
the solution. Baking soda is sodium bicarbonate and will react with any acid to release
carbon dioxide gas. Indeed it is called “baking” soda because it can react with acidic
ingredients in recipes such as yogurt to make pastry dough rise by forming pockets of
carbon dioxide. “Sour salt” is just the common name for citric acid, and combining it with
baking soda will produce a fizz. And that has commercial applications. Alka Seltzer
features both sodium bicarbonate and citric acid. Drop a tablet into a glass of water and it
fizzes with impressive vigour. The fizzing sends a message to the consumer that something
is happening. Indeed it is. Carbon dioxide is being released. What does that have to do
with any medicinal effect? Not much.
Alka Seltzer is meant to be taken if an upset stomach or “heartburn” is accompanied by a
headache. Heartburn can be caused by excess acid in the stomach which can be readily
neutralized by a base. Sodium bicarbonate itself could do a good job, but if you just
dissolve bicarbonate in water there is no fizz. However, when citric acid is included as well,
a reaction takes place producing sodium citrate with the release of carbon dioxide. Sodium
citrate is an effective antacid. As far as the headache goes, Alka Seltzer treats it with
aspirin. It contains acetyl salicylic acid which reacts with sodium bicarbonate to yield
sodium acetyl salicylate. This is very soluble and leads to fast absorption. The same effect
could be obtained just with a mixture of aspirin and baking soda, but then there would be
no plop plop fizz fizz to boost sales.
The same combo of sour salt and baking soda is used to put a fizz into the sales of the
“Ballistic Bomb.” The advertising is clever. “Feel Good in the Southern Hemisphere! Try a
Ballistic Bomb.” The marketers weren’t talking about hitching a ride aboard a missile to
Australia. They were talking about the Southern Hemisphere of the body. The part that is
immersed in the water in a bath. The Ballistic Bomb is a hardened cake of chemicals that is
designed to be dropped into the bath water. It produces vigorous fizzing, supposedly the
cause of pleasure in the “Southern Hemisphere,” while releasing a plethora of scents which
claim to relax the bather and put a smile on his or her face. Different bombs have different
scents. They range from “aphrodisiac jasmine” and “soothing rose” to “Sicilian orange” and
“neroli” which costs “an absolute fortune” but is guaranteed to put anyone in a good mood.
Essentially the Ballistic Bomb is a giant Alka-Seltzer tablet, without the medication. Baking
soda is cheap, and citric acid is also an economical solid acid with “natural” overtones. In
fact, the advertising for the Ballistic Bomb plays up the fact that citric acid is natural. This
of course is irrelevant. Citric acid, or sour salt, is produced by the mycological fermentation
of crude sugar solutions such as molasses with strains of Aspergillus niger. If it were
chemically synthesized, it would still do the same thing. Citric acid is citric acid, no matter
how it is made. What is clear is that when it is combined with sodium bicarbonate and
dropped into the bath, a massive amount of carbon dioxide is released. A pretty interesting
sensation but unfortunately the fizzing doesn’t last very long and the effect on the “southern
hemisphere” is pretty limited. I think I’ll stick to the jacuzzi. Although I must admit that
scent of “neroli” which is derived from the essential oils of the flowers of the orange tree,
and named after the Italian princess who discovered it, is more appealing than the aroma of
chlorine emanating from the jacuzzi.
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Office for Science and Society