chapter 10-Reactions rates and equilibrium Flashcards
(21 cards)
what is the rate of chemical reactions meaning
the change in concentration of a product or reactant overtime
how can the rate of reaction be found
by measuring how a reactant is used or a product is made it all depends on the physical property of the reactant or product
what is the collision theory
the colliding particles must have enough energy to break existing bonds
what is activation energy
minimum energy needed for a reaction to take place
different reactions have different activation energies
the lower the activation energy the larger the number of particles can react
what is the effect of conc on rate of reaction
when conc is higher there are more particles so more frequent collisions so more kinetic energy so rate increases
opposite for decrease
what is the effect of pressure on rate of reactions
same as concentration
how to work out rate of reaction from a graph
use a tangant
what is a catalyst
increases rate of reaction without being used up over the whole reaction
it allows a reaction via a different route with lower activation energy
what is a homogenous catalyst
same state as the reactant
e.g in the reaction o3+o=2o2 the chlorine radical is the catalyst as its the same physical state as the oxygen
what is a heterogeneous catalyst
in different state from reaction
e.g the iron catalyst in the habour process stays solid rather then gas
why do industries use catalyst
most reactions require high temps and pressure ,using a catalyst to lower these reduces the energy demand so it prevents amount of co2 in atmosphere and saves money
what is boltzmann distribution used to represent
the energy or particles
give an overview of the boltzmann curve
not summetrical
most particles have energy that falls in a narrow range
no particles have 0 energy
the total area under is equal to the total number of gas particles
if the shaded part on the boltzman curve is bigger what does this mean
greater number of particles
faster rate of reaction
if you add a catalyst to boltzmann curve what happens
it doesnt change the distribution curve but activation energy is lower
meaning more molecules will react to form product and rate of reaction increases
what is dynamic equilbrium
a state in a closed system where a reversible reaction has reached a point where the rates of the forward and reverse reactions are equal
what is the effect of changing the conc on the equilibrium position
if one reactant increases it shifts right to decrease the concentration
if one reactant decreases it shifts left to increase concentration
what is the effect of changing the temp on equilibrium postion
-if the forward reaction is exothermic and backwards is endothermic
-when the temp increases the equilibrium shifts towards the endothermic direction
-when temp decreases shifts toward the exothermic
what is the effect of changing the pressure on the equilibrium position
when the pressure increases it shifts to the side with fewer gas molecules to decrease pressure
- if pressure decreases it shifts towards place with more gas molecules
what is the effect of catalyst on position of equilibrium
it doesnt effect the position
how do you calculate equilibrum constant
look in the book page 65
