Exercise M.11 - Part (c)

[Amy Wu 1D]

A reaction vessel contains 5.77 g of white phosphorus and 5.77 g of oxygen. The first reaction to take place is the formation of phosphorus(III) oxide,
P4O6: P4(s) + 3 O2(g) --> P4O6(s). If enough oxygen is present, the oxygen can react further with this oxide to produce phosphorus(V) oxide, P4O10: P4O6(s) + 2O2(g) --> P4O10(s). (a) What is the limiting reactant for the formation of P4O10? (b) What mass of P4O10 is produced? (c) How many grams of the excess reactant remain in the reaction vessel?

For (c), which reaction's excess reactant is being referred to? Is it the excess reactant in the first reaction (P4O6) or the second reaction (P4O10)?

[alexis castro 1B]

It is referring to the excess amount of reactant in the second reaction.