Reaction Rates and Equilibrium

Question 1

What is a Reaction Rate?

Answer 1

This is a measure of how fast a certain reaction takes place, measuring how quick a product is formed/used!

Question 2

What are the 3 Ways of finding Rate of Reaction?

Answer 2

• Conc Change/ Time = mol/dm3
• Mass Change/Time = g/s
• Vol Change/Time = cm3/s

Question 3

How does Temprature affect Reaction Rate?

Answer 3

• Temp Increase = Rectant particles gain thermal energy, converted into kinetic energy
• Faster moving particles = increased frequency of particle collision, with more frequent, successfull particle collision, increased RofR!

Question 4

How does Concentration affect reate of reaction?

Answer 4

• Conc Increase = More particles per unit volume, more frequent, successfull collisions!
• Increased number of moles of particles per unit volume!, all being MUCH CLOSER TOGETHER!!

Question 5

How does Pressure affect Raction Rate?

Answer 5

• In gasses, pressure increase = particles subject to a smaller volume, for same number of moles of gaseous particles
• This will mean closer particle proximities, meaning more frequent, successfull collisoins per unit time!

Question 6

How does Surface Srea affect Reaction Rate?

Answer 6

• Increase in SA:V Ratio will mean more particles exposed for particle collisions
• More frequent, successfull collisions per unit time!

Question 7

How does catalysts affect rate of reactions?

Answer 7

• This will provide an alternate reaction pathway!
• This will mean a decrease in activation energy, meaning a greater proportion of particles with SUFFICIENT ENERGY to undergo M.S.F.Colls!

Question 8

What is an Intermediate??

Answer 8

This is a species formed during a reaction that reacts further, that is NOT PRESENT IN THE FINAL PRODUCTS!!!!!

Question 9

What does a catalyst really do?

Answer 9

• NOT used in chemical reaction
• Can react with reactant to form a termporaty intermediate!

“Catalyst will react with reactant to form intermediate, where immediate will break down to give product, while catalyst regenerates“

Question 10

What are Homogenous Catalysts?

Answer 10

1. These are catalysts with SAME PHYSICAL STATE AS REACTANTS!

Question 11

What are examples of Homogenous Catalysts?

Answer 11

1. Ethanol + Ethanoic Acid > Ester + Water [sulfuric acid as catalyst] ((all liquid))
2. Ozone Depletion into Oxygen&raquo_space; [Cloride ion radical as catalyst] ((all gasess))

Question 12

What are Heterogenus Catalysts?

Answer 12

• These are catalysts with DIFFERENT PHYSICAL STATES to the reactants
• Usually** solids with gasous reactants**, in solution
• Reactants molecules are ABSORBED onto catalyst surface, reaction occurs, and products leave via DESORPTION!

Question 13

What are examples of Heterogenous Catalysts at work?

Answer 13

1. Making Ammonia! [iron catalyst]
2. Alkene Hydrogenation (adding H2) [nickel catalyst]