What fact about elements would explain why two elements would bond with the same element in the same proportion?

Zinc + lead(ii) nitrate yield zinc nitrate + leadwhat's the chemical equation for this?

How many liters of hydrogen gas will be produced at stp from the reaction of 7.179×10^23 atoms of magnesium with 54.219g of phosphoric acid (h3po4) the equation is 3mg + 2h3(> mg(po4)2+3h2

Compare the equilibrium constants for the systems shown in the table. which favors products the most? which favors products the least? rank these systems in order from most to least in terms of favoring products rather than reactants. d > b > a > c c > a > b > d b > c > d > a a > d > c > b