The combustion reaction of propane is described by the reaction. c3h8 + 5o2 → 4h2o + 3co2. how many moles of o2 are required to generate 3 moles of co2? a. 2.5 moles b. 3 moles c. 4 moles d. 5 moles

C₃H₈   +   5 O₂   →   4 H₂O   +   3 CO₂

mole ratio based on balance equation of  O₂   :   CO₂ i  s    5  :  3
                      C₃H₈   +   5 O₂   →   4 H₂O   +   3 CO₂

∴ if moles of CO₂  =  3 moles
 
then moles of O₂  = (3 moles ÷ 3) × 5
                             
                             =  5 moles   (OPTION D)

Answerthis solution will not form a precipitateexplanationsolubility equilbrium:         pbf₂(s)  ⇄ pb²⁺(aq) + 2 f⁻(aq)the solubility product expression is    (we exclude solids from the equilibrium expression).now suppose we have the trial ion product q, which we can define as    then, we can interpret  q as the product of the concentration of the ions that we have and ksp as the product of the ion concentrations that are needed to form a saturated solution.if q > ksp, then that implies that there will be a surplus of ions that exceed the amount that is required to form a saturated solution. a precipitate will then form (the precipitate continually  forms until the surplus ions are removed and q is decreased to ksp's value).if q = ksp, the saturated solution that forms is barely saturated and the precipitate will be minimal.if q < ksp, then the ion concentration will not be enough to form a saturated solution (so no precipitate).using our information, we calculate the trial ion product:     since q = 2.7  × 10⁻⁸ < ksp =  4  ×  10⁻⁸, a precipitate will not form.