We are given with
136 g P4
excess oxygen
The complete combustion reaction is
P4 + 5O2 => 2P2O5
Converting the amount of P4 to moles
136/123.9 = 1.098 moles
Using stoichiometry
moles P2O5 = 1.098 x 2 = 2.195 moles P2O5
Answer:

Explanation:
Hello,
In this case, given the described concept regarding the Avogadro's number, we can easily notice that 27.0 g of aluminium foil has 6.022x10²³ atoms as shown below based on the mass-mole-particles relationship:

Notice this is backed up by the fact that aluminium molar mass if 27.0 g/mol.
Best regards.
HA is a weak acid so there should be little amount of HA and then H+ and A- in the beaker so the last one is true a weak acid never converts completely to H+ and A-