On strongly heating 2.76 g of Ag2CO3(s), it decomposes completely according to the reaction: Ag2CO3(s) → 2Ag(s) + CO2(g) + 12O2(g). Determine the mass of the solid residue left behind. (Molar mass of Ag2CO3 = 276 g/mol, Ag = 108 g/mol)

50.0 kg of N2(g) and 10.0 kg of H2(g) are mixed to produce NH3(g). Identify the limiting reagent in the reaction N2(g) + 3H2(g) → 2NH3(g).