system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does Emergen-C make carbonated drinks lose their fizz?

I like to mix Emergen-C with Sprite or Sierra Mist. When I pour the packet in a glass with a carbonated drink it I have to do it slowly or the foam will keep building and spill over the glass. After it's done, my soda is flat. What is in Emergen-C that makes it react so strongly to carbonation?
gpt
I think it has to do with nucleation sites. The tablet gives bubbles a good place to form. The bubbles form easily because the liquid is super saturated with CO2, and so they "want"  to leave solution. 

The same reason diet coke and mentos fountains work. The bubbles are just waiting for an easy way to release their energy.