[CHEM] Unit 11- Kinetics Flashcards
In order to react, reactants need to have:
Effective collisions
Two things are needed for effective collisions:
1) Enough energy
2) Proper orientation (based on polarity)
To react quickly, ionic reactants need to be in the ___ phase
Aqueous (aq)- solid ionic reactants don’t break apart
Covalent reactants typically have ___ bonds to break and so react ___
More, slowly
Temperature is a measure of the:
Average kinetic energy of the particles
A high temp leads to ___ energy, and so ___ particles will collide with sufficient energy
Higher, more
A high temp also leads to:
Particles moving faster, and so more total collisions will occur
How does concentration affect rate?
Higher concentration=faster rates because there are more total collisions
Pressure only affects ___ reactants
Gas
How does pressure affect rate?
Pressure is caused by the particles colliding with the walls of the container- more collisions will walls will mean more collisions between particles
How does surface area affect rate?
Reactions only occur at the surface where the reactants are in contact; therefore, as surface area increases, there will be more total collisions (and in turn more effective collisions)
Trick to remember: Sugar cubes vs powdered sugar
How does one increase surface area?
For solids, grind them into small pieces
For liquids, stir
How does a catalyst affect rate?
Catalysts reduce the required energy for an effective collision, thereby making more (already existing) collisions effective
T/F: A catalyst is used up during a reaction
F
Endothermic=
Heat put in (heat is a reactant)
Breaking/forming a bond is endothermic
Breaking!
Exothermic=
Heat is released (heat is a product)
Breaking/forming a bond is exothermic
Forming!