Balance the following equations. Enter 1 as a coefficient for reactants and products which have no coefficient. (NH4)2Cr2O7(s) _> Cr2O3(s)+N2(g)+H2O(g)

For the reaction shown, find the limiting reactant for each of the following initial amounts of reactants. 4al(s)+3o2(g)→2al2o3(s) a) 1 molal, 1 mol o2 b) 4 molal, 2.6 mol o2 c) 16 molal, 13 mol o2 d) 7.4 molal, 6.5 mol o2