Chemistry of Soda

Hopewell Valley Student Podcasting NetworkChemistry ConnectionsChemistry of SodaEpisode #8  

Welcome to Chemistry Connections, my name is Neha and Nikhil and we are your hosts for episode #8 called Chemistry of Soda. Today we will be discussing basically that: the chemistry involved in soda.

Segment 1: Introduction to SodaSoda is a fizzy beverage that people love to drink, ourselves includedThere are many different kinds of soda. To name a couple: CokeFantaRoot beerPepsi And moreYou can find it at any local grocery storeIt is an enjoyable drink due to its carbonation and the sting it has on your tongue, which we will go into depth about shortly
Segment 2: The Chemistry Behind Soda

Topic 1: Equilibrium

First, let’s talk about the fizz in sodaCitric acid reacts with the carbonate in bicarbonate of soda to form carbon dioxide gas These bubbles of carbon dioxide gas are what make your drink fizzyThese molecules of carbon dioxide are thoroughly mixed and dissolved into the water in the soda popThis is known as carbonationRegarding carbonation, it is important to note: Carbon dioxide doesn’t easily dissolve in water under everyday conditionsManufacturers have to increase the pressure in the can and keep it at a low temperature so water molecules can trap lots of carbon dioxide moleculesThey also use pressure to put more gas in water than it could normally hold at that temperatureTherefore, if the soda can warms up a bit or the can is shaken, pressure goes up and extra gas is ready to come upSo opening the can releases pressure, and soda shoots outThis is why the can is sealed so that it is airtight. That way, the inside of the can maintains enough pressure to prevent extra carbon dioxide molecules from escaping

Hopewell Valley Student Podcasting NetworkChemistry ConnectionsChemistry of SodaEpisode #8  

Welcome to Chemistry Connections, my name is Neha and Nikhil and we are your hosts for episode #8 called Chemistry of Soda. Today we will be discussing basically that: the chemistry involved in soda.

Segment 1: Introduction to SodaSoda is a fizzy beverage that people love to drink, ourselves includedThere are many different kinds of soda. To name a couple: CokeFantaRoot beerPepsi And moreYou can find it at any local grocery storeIt is an enjoyable drink due to its carbonation and the sting it has on your tongue, which we will go into depth about shortly
Segment 2: The Chemistry Behind Soda

Topic 1: Equilibrium

First, let’s talk about the fizz in sodaCitric acid reacts with the carbonate in bicarbonate of soda to form carbon dioxide gas These bubbles of carbon dioxide gas are what make your drink fizzyThese molecules of carbon dioxide are thoroughly mixed and dissolved into the water in the soda popThis is known as carbonationRegarding carbonation, it is important to note: Carbon dioxide doesn’t easily dissolve in water under everyday conditionsManufacturers have to increase the pressure in the can and keep it at a low temperature so water molecules can trap lots of carbon dioxide moleculesThey also use pressure to put more gas in water than it could normally hold at that temperatureTherefore, if the soda can warms up a bit or the can is shaken, pressure goes up and extra gas is ready to come upSo opening the can releases pressure, and soda shoots outThis is why the can is sealed so that it is airtight. That way, the inside of the can maintains enough pressure to prevent extra carbon dioxide molecules from escapingTalking about the can being sealed airtight, inside the can, carbon dioxide exists in two forms: some dissolves in water and some sits in gas form between the top of the can and the liquidWhen carbon dioxide dissolves in water, water and gaseous carbon dioxide react to form a dilute solution of carbonic acid (H2CO3)This reaction is reversibleWhen the can of soda is sealed, the high pressure inside the can forces the chemical reaction to the right (forward reaction)This forward reaction continues until equilibrium is reachedHowever, once you open can, pressure is released and the reaction shifts to the left (so reverse reaction occurs)In the reverse reaction, water and carbon dioxide are formedThis is because the gaseous carbon dioxide at the top of the can escapes when you open the canThe can is no longer under pressure if it is open, so dissolved carbon dioxide starts coming out of the solution (reverse reaction)Bubbles form which release the carbon dioxide into the airThe escaping carbon dioxide lowers the concentration of carbon dioxide in the drink, so carbonic acid turns back to carbon dioxide and water which results in a new eqmNow that we’re on the topic of bubbles that release carbon dioxide, let's talk about the fizz of soda going away with timeI think it’s known to most people, excluding Nikhil, that fizzy soda tastes better than flat sodaIn a fizzy drink, dilute carbonic acid creates a slight burning sensation on your tongue, which is enjoyable to someThis doesn’t happen with a flat drink thoughLet’s start with how the drink becomes flatIf you open a soda can or bottle, the carbon dioxide begins to come out of the soda and into the airEventually, enough carbon dioxide will come out and the soda will become flatWhen soda is flat, carbon dioxide continually escapes which is why there is no stinging sensation when soda is flatLet’s recall the reaction from earlier where water and carbon dioxide react to form carbonic acidAs carbon dioxide bubbles away from liquid, the reactants and products move again towards equilibrium which causes the reverse reaction to take over since carbon dioxide, a reactant, is going away so the reaction proceeds in that direction to create more of itThis causes carbonic acid concentration to get lower and lowerTherefore, as the amount of carbonic acid in the beverage goes down, so does the soda’s ability to bring about the tingling sensation on your tongue

Topic 2: Acidity/pH

Now that we’ve talked about carbonic acid, let’s talk about other acids in sodaPhosphoric acid and citric acid are added as preservatives and flavor enhancersCitric acid specifically can bind to calcium and leach it out of teeth, which is dangerousEvery soda on the market has a pH below 4, most between 2.5 to 3.5The acidic pH of soda makes it dangerous for teethThis is because acid is an instrumental part of the cavity processThe acidic pH of soda gives bacteria even more power to cause cavities by lowering the pH in the mouth and weakening enamel, Eventually, the enamel gets weak to the point where it cannot fight the acid attacks of bacteria wellSugar in soda also feeds bacteria, which produce acid that dissolves enamelThese sugars in soda include a mixture of a sugar called glucose and another called fructoseThese wo sugars attach to each other to make another sugar called sucroseAnyway, back to the acidity of sodaThe acidity of soda and absorption of carbon dioxide both can also cause a significant decrease in blood pHThis lower blood pH can possibly be associated with many diseases (including incurable cancer) because the body needs an alkaline environment for good health
Segment 3: Personal ConnectionsSoda is one of my favorite drinks (in my top 3)So we thought it would be cool to take a dive into the chemistry behind soda, especially with the fizz since Neha likes fizzy soda but Nikhil does notIt was interesting to find out how the fizz works and why it fades away as time goes onWe really just chose it because it was a fun topic and soda is still something we drink weekly so it kind of is still a big part of our lives, even if it isn’t in a significant way

Thank you for listening to this episode of Chemistry Connections. For more student-ran podcasts and digital content, make sure that you visit www.hvspn.com. 

Sources:

https://www.york.ac.uk/res/sots/activities/itsagas.htm#:~:text=The%20citric%20acid%20reacts%20with,what%20make%20your%20drink%20fizzy. 

https://www.acs.org/education/whatischemistry/adventures-in-chemistry/secret-science-stuff/soda-pop.html

https://letstalkscience.ca/educational-resources/stem-in-context/chemistry-pop  

http://ijariie.com/AdminUploadPdf/Chemistry_of_Soft_Drinks_ijariie11653.pdf

https://www.prodentcare.com/blog/why-soda-is-terrible-for-your-teeth#:~:text=What%20makes%20soda%20acidic%3F,as%20preservatives%20and%20flavor%20enhancers. 

https://www.premierdentalohio.com/blog/effects-of-drinking-pop-soda-on-dental-health#:~:text=Acidic%20pH,battery%20acid%20is%20about%201.0. 

https://www.medindia.net/patients/lifestyleandwellness/colas-are-bad-for-health-in-the-long-run.htm#:~:text=Carbon%20dioxide%20is%20the%20end,the%20blood%20making%20it%20acidic. 

Music Credits

Warm Nights by @LakeyInspired 

Subscribe to our PodcastApple PodcastsSpotifyGoogle Podcasts  Stitcher  
Connect with us on Social Media@theHVSPN