CO2 forms from water and antacid tablet

In summary: It seems like the confusing part for you is why the final concentration in trial #3 was significantly higher than in trials #1 and #2. This could be due to a wet flask or vial affecting the results. A wet flask or vial could introduce more water into the reaction, causing more CO2 to be produced and resulting in a higher concentration of CaCO3. However, it is important to also consider if there were any other variables or errors that could have affected the results in trial #3. Overall, it is important to carefully consider and evaluate all possible factors when analyzing experimental data.
  • #1
grantaere
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Homework Statement


For a chemistry lab, we're trying to find the amount of CaCO3 in an antacid table by measuring the change in pressure due to the reaction of CaCO3 with HCl to produce CO2. This question in the lab report is confusing me to no end...

Let’s say the % concentrations of CaCO3 (Table 5) you obtain from trial #1 and #2 are in good agreement, while the concentration obtained from trial #3 is significantly higher. Can a wet flask or vial be responsible for such results? Answer by yes or no and explain in great detail.

Homework Equations


https://docs.google.com/file/d/0By9VwoUlJRdCMzgxYjM1YzQtODA3MS00YmM5LWJiNjYtYmRlNDUwNDNjYTI3/edit
PV=nRT

The Attempt at a Solution


I feel as though the obvious answer is that the percentage concentration should go down, not up, since gas is lost and therefore final pressure is lower than it should be... but then again, why would water kickstart/affect the reaction in the first place if it's not water but HCl that the antacid reacts with? I'm just really confused with this question, any help would be enormously appreciated.
 
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  • #2
grantaere said:
I feel as though the obvious answer is that the percentage concentration should go down, not up, since gas is lost and therefore final pressure is lower than it should be...
Develop this idea --- you're doing fine.
grantaere said:
why would water kickstart/affect the reaction in the first place
This is what's bothering you? Ever see an Alka-Seltzer commercial?
 
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  • #3
I just went and watched the commercial and I see that yeah, water does react quite strongly with the antacid tablet. I'm still not understanding the reaction going on here there, though- does calcium carbonate react spontaneously with water to form CO2? (I was under the impression that it's insoluble, but I could be wrong...)
 
  • #4
Bystander said:
This is what's bothering you? Ever see an Alka-Seltzer commercial?

Alka-seltzer contains sodium bicarbonate and citric acid. http://en.wikipedia.org/wiki/Alka-Seltzer
If this is the kind of tablet being used, then water alone could initiate the reaction between the bicarbonate and the citric acid. Since the instructions say that a little water could start the premature evolution of gas, this is likely the kind of antacid that they have given you. You are correct that CaCO3 is insoluble in water (this is what seashells are made of, after all).

Bystander is correct, though, with the statement that you are on the right track with your idea about the final pressure being lower.
 
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  • #5


It is possible that a wet flask or vial could be responsible for the higher concentration obtained in trial #3. This is because the presence of water can affect the reaction between CaCO3 and HCl. When water is present, it can react with the HCl to produce H2O and CO2, which can contribute to the overall pressure change and make it seem like there is more CO2 being produced from the reaction between CaCO3 and HCl. This can lead to a higher concentration being calculated.

Another possibility is that the wet flask or vial could introduce impurities or contaminants that can react with the HCl and produce additional CO2. This would also contribute to a higher concentration being calculated.

To avoid these potential sources of error, it is important to make sure that all equipment used in the experiment is completely dry and free of any impurities or contaminants. This will ensure that the only reaction taking place is between the CaCO3 and HCl and that the resulting concentration is accurate. Additionally, repeating the experiment multiple times and taking the average of the results can help to reduce the impact of any potential errors caused by a wet flask or vial.
 

FAQ: CO2 forms from water and antacid tablet

What is the chemical reaction that creates CO2 from water and an antacid tablet?

The chemical equation for this reaction is: H2O + NaHCO3 → NaOH + CO2 + H2O. The water reacts with the sodium bicarbonate (antacid tablet) to form sodium hydroxide, carbon dioxide, and more water.

Why does CO2 form from water and an antacid tablet?

The main reason for this reaction is the acidity of the antacid tablet. When it comes into contact with water, it releases carbon dioxide gas as a byproduct. This helps to neutralize excess stomach acid and relieve symptoms of heartburn or indigestion.

Is the formation of CO2 from water and an antacid tablet an exothermic or endothermic reaction?

This reaction is exothermic, meaning it releases heat as a result of the chemical reaction. This is why you may notice the tablet fizzing and becoming warm to the touch when dropped into water.

Can the amount of CO2 produced from this reaction be controlled?

Yes, the amount of CO2 produced can be controlled by varying the amount of water and antacid tablet used, as well as the temperature of the water. More water and a higher temperature will result in a faster and more vigorous reaction, producing more CO2.

Are there any safety concerns when conducting this experiment?

While this reaction is generally safe, it is important to handle the antacid tablets and resulting CO2 gas with caution. The tablets may contain other ingredients that could be harmful if ingested in large quantities, and the CO2 gas can displace oxygen in an enclosed space. Always follow proper safety precautions and consult a professional before conducting any experiments.

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