Answer: Hydrogen that is not used in balloons because hydrogen burns very easily.
pls mark brainliest
<span>If you look at the chlorine box, with the symbol Cl, you see the atomic mass is equal to 35.453 atomic mass units. This is the weighted average mass of chlorine, including its isotopes, as found in nature. This also means that one mole of chlorine atoms has a mass of 35.453 grams.</span>
<span>The question does not mention the brand or size of antacid tablets, but some research in the internet shows that for a very common brand, Alka Seltzer, that it takes about 4 tablets to produces 60 mL of gas. So for 120mL it will take 120/60 x 4 or 8 tablets to produce 120 mL of CO2 gas.</span>
