A summary of topic 9, organised so the notes are easy to understand. The notes are on slides, so they can be printed out and used as revision cards or posters, for revision on the go. The notes cross-reference the specification so it is easy to see where each bit of information has come from. They ...
Collision theory: Homogeneous catalysts:
= for a reaction to take place particles must collide with the = catalyst in same state as reactants
correct orientation and an energy>/=Ea (successful collision) E.g. acidified potassium dichromate in organic mechanisms
Rate of reaction: Heterogeneous catalysts:
= change in [reactants or products] / time = catalyst in a different state to reactants
From a graph = gradient of tangent E.g. haber process
To increase rate: N2 (g) + 3H2 (g) ⇌ 2NH3 (g) cat = Fe(s)
↑ temp How heterogeneous catalysts work:
- ↑ rate = ↑ KE ∴faster ∴↑successful collisions 1. ADsorption - reactants adsorb onto catalyst surface by
- ↑particles have E>Ea ∴↑successful collisions forming bonds with the catalyst
↑ conc 2. Reaction - bonds in reactants break (due to new
- ↑ likely to collide ∴↑successful collisions strong bonds formed w/ catalyst) & product formed
↑ pressure 3. Desorption - product leaves catalyst surface
- ↑ likely to collide ∴↑successful collisions Poisoning = blocking active sites - adsorb and wont desorb
↑ SA (solids) Catalytic converters
- ↑ particles available to collide∴↑successful collisions = thin metal catalyst coating & honeycomb structure to ↑ SA
+ catalyst and ↓ metal used
- Lowers Ea ∴↑particles have E>Ea ∴↑successful - Use Pt ot rhodium catalysts (expensive)
collisions Remove CO & NO from vehicle exhausts:
1. 2NO → N2 + O2
2. O2 + 2CO → 2CO2
∴ 2NO + 2CO → N2 + 2CO2
Catalysts:
← reaction profile
Catalysts provide
alternative routes that
have a lower Ea.
They ↑ rate = products are
made faster ∴ saves time
and money
Also ↑ rate = no need for ↑
heat (saves fuel) ∴
reduces pollution
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller laurelgracefell. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.87. You're not tied to anything after your purchase.
