random Flashcards
Why is platinum and nickel a good catalyst
because they adsorb strongly enough to hold and activate the reactants, but not so strongly that the products can’t break away.
why is silver to tungsten a bad catalyst
Silver, for example, isn’t a good catalyst because it doesn’t form strong enough attachments with reactant molecules. Tungsten, on the other hand
what do catalytic converters so and with what catalysts. how is it made to be more efficient
Catalytic converters change poisonous molecules like carbon monoxide and various nitrogen oxides in car exhausts into more harmless molecules like carbon dioxide and nitrogen. They use expensive metals like platinum, palladium and rhodium as the heterogeneous catalyst.
The metals are deposited as thin layers onto a ceramic honeycomb. This maximises the surface area and keeps the amount of metal used to a minimum.
what is catalytic poisoning
when something which isn’t a part of the reaction gets very strongly adsorbed onto the surface of the catalyst, preventing the normal reactants from reach
What is the contact process used for
making h2so4
what catalyst is used in contact process, is this homo or heterogenous
give equation
During the Contact Process for manufacturing sulphuric acid, sulphur dioxide has to be converted into sulphur trioxide. This is done by passing sulphur dioxide and oxygen over a solid vanadium(V) oxide catalyst.
what catalyst is used interaction of persulphate ions and iodide ions and why + equation
The reaction needs a collision between two negative ions. Repulsion is going to get seriously in the way of that!
The catalysed reaction avoids that problem completely. The catalyst can be either iron(II) or iron(III) ions which are added to the same solution.
This is another good example of the use of transition metal compounds as catalysts because of their ability to change oxidation state.
What happens if you use iron(III) ions as the catalyst instead of iron(II) ions?
The reactions simply happen in a different order.
equation and catalyst used in harber process
Equation for process of catalytic converting in engines + catalyst
equation for reaction of Mn04- and C204-
2MnO₄⁻ (aq) + 8H⁺(aq) + 4Mn²⁺(aq) → 5Mn³⁺(aq) + 4H₂O(l)
2Mn³⁺(aq) + C₂O₄²⁻(aq) → 2CO₂(g) + 2Mn²⁺(aq)
2MnO₄⁻ (aq) + 8H⁺(aq) + 5C₂O₄²⁻(aq) → 2Mn²⁺(aq) + 4H₂O(l) + 10CO₂(g)
explain graph of conc vs time between manganate and ethadioate ions
slow due to repulsion in beginning
steep gradient/fast reaction due to intermediate catalyst formation
slow at end due to running out of reactants
