STUDYING ACIDS AND BASES IN LIQUID
Obinna Modilim
Cary Academy
ABSTRACT
The purpose of this experiment was to see how different liquids were affected by an
antacid tablet. pH was studied in these experiments with pH strips and antacid tablets,
and these were not the only one done. Different liquids had their pH tested before and
after an antacid sat in it for 60 sec. Coke was one of the most acidic, yet it had the
largest change. It is because of the property that makes Coke dissolve the tablet.
INTRODUCTION
pH measures how acidic or basic a chemical is. Acidic and basic chemicals are
opposites. When mixed together, the acid and base chemicals are neutralized. pH is
measured on a scale of 1 to 14. This is known as the pH scale. Number 7 on the pH
scale is neutral. One neutral substance is pure water. When things are added to water,
it can either become acidic or basic, depending on the substance added to the water.
Chemicals that are very far on either side of the pH scale are chemicals that are
extremely acidic or basic. These are known as reactive chemicals. Reactive chemicals
can sometimes cause burns. This makes it very important to be cautious when dealing
with reactive chemicals.
pH strips are strips of paper with one or more indicators inside it. pH strips are tools for
finding the pH of different liquids. When a pH strip is dipped into a liquid, its color
changes. Each color represents a different level of pH. Different pH strips have different
ranges and sensitivity. The more sensitive a pH strip is, the smaller its range is, and
vice versa. pH strips have different colors for each level of acidity. A color legend shows
which color stands for which level of pH. Color legends are made by putting the pH strip
in a liquid where the level of acidity has been identified. The companies that
manufacture pH strips usually sell the color legend with them, so there is no reason to
worry about it.
Antacids are special medicines that have to do with pH. They neutralize, or counteract
acids in in the human stomach. The main ingredients for an antacid tablet are aluminum
hydroxide, magnesium carbonate, and magnesium trisilicate. Antacids can actually be
in a tablet or in liquid form. The reason antacids neutralize acids is because antacids
are bases, which are opposites acids. When they combine, the antacid and stomach
fluids average out, and the stomach acids are neutralized.
A couple of experiments previously done before were similar to these experiments.
Beakers, water, lemon juice, Tums, Prevacid, Pepto-Bismol, baking soda, vinegar,
stopwatches, and a pill cuter were used in the following experiments. Every experiment
was repeated three times for accuracy. In one of the experiments, 100 mL of water and
60 mL of lemon juice were mixed in a beaker. Different brands of antacids were used
and left in the tablet for 60 sec. The pH was measured before and after the tablet.
Another experiment used the same amount of water and lemon juice. This time though,
Pepto-Bismol was added for different amounts of time. The pH was recorded before and
after the tablet was added. The third experiment was a little different. There was still 60
mL of lemon juice, but different amounts of water were added to see if they changed the
level of pH. As usual, the pH levels were measured before and after the variables were
added. Yet another experiment was based on the consistencies of Tums. It was left in
100 mL of water and 60 ml of lemon juice. The pH was tested both before and after
Tums antacid tablets were put in the mix. In the next experiment, baking soda was used
in place of an antacid tablet. There were 100 mL of water and 60 mL of lemon juice
used, and the baking soda was left for 60 sec. Another experiment was done to see if
the color of a Tums tablet affects how the antacid tablet changes the pH of the liquid. It
stayed for 60 sec, and the pH levels were tested before and after the colored antacids
were put in the mix of water and lemon juice. One of the other experiments was done to
see how a Tums antacid tablet affects the pH level of different types of acidic liquids.
Each type of liquid had 50 mL each time, and one Tums antacid tablet was dropped in
for 60 sec. The last known previously done experiment was kind of like a reversal to one
of the other previously done experiments. There were 100 mL of water, along with a
different amount of lemon juice every time. A Tum antacid tablet was dropped in and
stayed in for 60 sec.
MATERIALS AND METHODS
For these experiments a beaker, stopwatch, Coke, Orange Fanta, Sprite, lemonade,
Equate antacid tablets, pH strips, a knife, and a color legend were used.
In the first experiment, 400 mL of Sprite was poured into a beaker. Then an antacid
tablet was put in for 60 sec. The pH of the Sprite was tested before and after the antacid
was added. This was done with Coke, lemonade, and Orange Fanta.
In the second experiment, 400 mL of Coke were poured into a beaker. An antacid tablet
was put in for 60 sec. This was done with the tablet whole, in thirds, and powdered. The
pH of the Coke was measured before and after an antacid was added.
In the third experiment, 400 mL of Coke were put in a beaker. Every time either ¼ of a
tablet, ½ of a tablet, 1 tablet, 2 tablets, and 3 tablets were left in the beaker for 60 sec.
The pH levels were measured before and after antacids were added.
In the fourth experiment, different amounts of Orange Fanta were poured into a beaker.
Each time an antacid tablet was left in it for 60 sec. For every amount, the pH was
measured before and after an antacid was added
The same thing in the fourth experiment was done in the fifth experiment. In the fifth
one, however, Sprite was used instead of Orange Fanta.
RESULTS AND DISCUSSION
7
6
pH Level
5
4
before tablet
3
after tablet
2
1
0
sprite
coke
lemonade
fanta
Type Of Drink
Figure 1. This shows how the acidities of drinks are affected by antacid tablets.
In this graph, coke was lowest on the pH scale, which meant it had the highest acidity,
Sprite, Fanta, and lemonade all had pH of four. Lemonade had the least pH change of
0, while Coke had the most pH change of 3. This happens because in order for the
tablet to work, it needs to dissolve first. While Coke can dissolve things, like when it rots
teeth, lemonade does not do that. Therefore, the antacid tablet cannot do its job.
8
7
pH Level
6
5
4
3
2
1
0
no tablet
1 whole tablet
tablet in thirds
powdered tablet
Tablet Condition
Figure 2. This table shows how the pH changes in Coke depending on how an
antacid tablet is split up.
In this experiment, the Coke was the most acidic when there was no antacid. It was the
least acidic when the tablet was powdered. The reason a powdered tablet neutralizes a
tablet in thirds better than one in thirds and as one whole tablet is because of how it
spreads. A whole tablet only neutralizes acids in one place. A powdered tablet spreads
in the drink, and covers more space at once.
8.00
7.00
pH level
6.00
5.00
4.00
3.00
2.00
1.00
0.00
0.00
0.50
1.00
1.50
2.00
2.50
3.00
amount of tablets
Figure 3. This shows how the amount of tablets effect pH levels in Coke.
The graph shows that Coke is the most acidic with no tablet, and is most neutral when 3
tablets are added. This shows that the more tablets in the drink, the more neutralized it
is. This is because when more antacids are added to the drink, the tablets are more
potent.
7
6
pH level
5
4
before
3
after
2
1
0
0
100
200
300
400
500
600
700
amount of liquid (mL)
Figure 4. Shows how antacids affect the drink of different amounts.
In this graph, the only time the pH changed was when the amount was 150 mL. At any
other amount, there was too much for the tablet to handle. The higher amounts have too
much to work.
7
6
pH level
5
4
before
3
after
2
1
0
0
100
200
300
400
500
600
700
amount of liquid (mL)
Figure 5. This is the same as Figure 4, but with Sprite
In the last graph, Orange Fanta was used. This time though, Sprite wasused instead of
Orange Fanta. The antacid tablet was able to neutralize every amount except for 600
mL. This shows that Sprite is not as resistant as Orange Fanta.
CONCLUSION
The experiment to see if how a tablet splits up changes its effect on pH showed that a
powdered tablet was stronger than a whole tablet. It was hypothesized that the whole
tablet would be stronger, but it was incorrect. These results are important because
costumers want to see how well the antacids they are buying work. Other experiments
that could be done in the future include testing different brands of antacids on different
drinks.
CITATIONS
“Acids, Bases, and pH.” app.discoveryeducation.com. Discovery Education, February
20 2014. Web. February 20 2014.
“Antacids” www.patient.co.uk. Fight Oesophageal Reflux Together, Living with Reflux,
February 20 2014. Web. February 20 2014.
Challoner, Jack, “Acids and Bases” the Visual Dictionary of Chemistry. Edition 1, New
York: DK Publishing, 1996, Print
EPA. “What is pH?” www.epe.com/acidrain EPA, December 4 2012. Web. February 2
2014.
Kollias, Helen. “Informal Experiments: How do pH strips work?”
www.precisionnutrition.com. Precision Nutrition Inc., February 20 2014. Web. February
20 2014
Newmark, Ann, “Acids and Bases” Chemistry. Edition 1, London: DK Publishing, 1993,
Print
Zimmerman, Claudia, Acid Neutralization, Cary Academy, 2013