How many grams of carbonic acid were produced by the 3.00 g sample of nahco

I think the given is 3 g sample of NaHCO3. then if it will be reacted with an acid, it will produce H2CO3.
 so the reaction NaHCO3 + HCl --> NaCl + H2CO3

mas of H2CO3 = 3 g NaHCO3 ( 1 mol NaHCO3 / 84 g ) ( 1 mol H2CO3 / 1 mol NaHCO3) ( 62.03 g / 1 mol )
mass of H2CO3 = 2.22 g H2CO3

He studied the way in which elements combined during chemical reactions.