Metal carbonates react with acid to produce a salt, water, and carbon dioxide gas as seen in the reaction below. Na2CO3(s)+2HCl(aq)→2NaCl(aq)+CO2(g) +H2O(l)

If 1.45 g of Na2CO3 reacts with an excess amount of HCl, what volume of CO2 will be produced at STP?

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements

the answer is a! (2.9 x 10^-18 j) hope i could someone. : )