Plz help write the compound formula

Sodium phosphate
Lead II nitrate
O4F8
BeC2O4
Tricarbon hexahydride
PBr5

For ai it's atomic number is 13 and it's mass number is 27 how many neutrons does it have

Consider the reaction: n2(g) + o2(g) ⇄ 2no(g) kc = 0.10 at 2000oc starting with initial concentrations of 0.040 mol/l of n2 and 0.040 mol/l of o2, calculate the equilibrium concentration of no in mol/l how would this be done?

Amixture with the same composition throughout is!