It’s Calcium hope that helps!
Carbon — pay attention to your periodic table trends
Starting mass: 294
Mass ratio: 3/5
The evidence that a chemical reaction occurred is can be change in color , formation of a precipitate , Here in the case when 6 m HCl to the solution of sodium acetylsalicylate, the formation of precipitate that is of aspirin takes places that can be taken as a evidence that a reaction is occured. The reaction can be seen in the image attached.