17C.2 Flashcards
what is a homogenous catalyst
a catalyst that is in the same phase as the reactants
what is the key feature of a homogeneous catalyst
the formation of intermediate species for which a specific formula was written
what is the equation for persulfate ions acting as oxidizing agents in a reaction with iodide ions
S2O8^-2 + 2I^- ——>2SO4^-2 + I2
why is the reaction between persulfate ions and iodide ions slow
because both of the reactant ion are negative so they repeal each other (S2O8^-2, and 2I^-)
what is the catalyst for the reaction between Persulfate ions and iodide ions
Fe^2+ in the aq phase as its a homogeneous catalyst
what are the steps for the reaction between persulfate ions and Iodide ions with an aq Fe^2+ catalyst
step 1; the persulfate and the iron don’t repeal each other because they have opposite charges so the persulfate oxidizes the iron (S2O8^-2 + 2Fe^2+ —–> 2SO4^-2 + 2Fe^3+)
step 2; the Fe^3+ would then oxidize the iodide ions since they don’t repeal because they have an opposite charge (2Fe^3+ + 2I^- —–> I2 + 2Fe^2+)
the iron(ii) that is used up in the first reaction is regenerated here so the two steps can be repeated continuously
what are the steps for the reaction between persulfate ions and Iodide ions with an aq Fe^3+ catalyst
step 1: the Fe3+ would react and oxidize the iodide ions since they don’t repeal (2Fe^3+ + 2I^- —–> 2Fe^2+ + I2)
Step 2: the Fe(ii) made in the first step would react and reduce the persulfate ions since they don’t repeal and have opposite charge (2Fe^2+ + S2O8^-2 —–> 2SO4^-2 +2Fe^3+)
the iron(iii) that is used up in the first reaction is regenerated so the two steps can repeat continuously
what is autocatalysis
when a reaction product acts as a catalyst for the reaction
why is the oxidation of ethanedioate ions by manganate(VII) slow
since both reacting species are negatively charged (MnO^-2, and C2O4^-2)
What does an autocatalysis graph look like
page 215
what is important for titrations to work well
for the reactions to be fast so the end point of the reaction can be accurately observed
what catalyst is used for the oxidation of ethanedioate ions by manganate(VII) slow
non Mn^2+ auto catalysis and is excepted as a homogeneous catalyst
