chemical change: rate & extent Flashcards
what is the effect on equilibrium in increasing concentration (reactant)?
-equil shifts to right to reduce effect of increasing con
when con of a reactant increases, equil moves to oppose change and create more product from excess reactant
what is the effect on equilibrium in decreasing concentration (reactant)?
-equil shifts to reactant side to increase concentration again
what is the effect on equilibrium in increasing temp (reactant)?
-equil moves in endo direction to reverse change
what is the effect on equilibrium in decreasing temp (reactant)?
-equil moves in exo direction to reverse change
what is the effect on equilibrium in increased pressure (reactant)?
-equil shifts in direction that produces smaller no. of molecules of gas to decrease pressure again
what is the effect on equilibrium in decreased pressure (reactant)?
-equil shifts in direction that produces larger no. of molecules of gas to increase pressure again
what’s normally used as catalysts?
-transition metals are used widely as catalysts: they have variable oxidation states allowing them to readily donate and accept different numbers of electrons
how do catalysts work?
catalysts work by attracting reactant molecules on to the surface (of catalyst) and so providing an alternate reaction pathway of lower energy
different chemicals store…
different amount of energy in bonds
what is a neutralisation reaction?
what does it produce?
-acid + base
-salt + water
in a reaction profile of an endothermic reaction, would reactants or products be higher
-products
-as it has more energy absorbed from surroundings
in a reaction profile of exothermic reaction, would reactants or products be higher
-reactants
-as it loses energy over time to surroundings, so products will have less energy
what is activation energy
-minimum amount of energy (that reactant particles) need(ed) in order to collide w/ e/o & react
what is an exo react.
-a reaction that releases thermal energy to surroundings
On reaction profile diagrams, the activation energy is always the….
increase in energy from reactants to peak of curve
pros and cons of hydrogen-oxygen fuel cells
pros
-only require H and O, both abundant
-don’t prod any pollutants as waste
-(fuel cells) simple devices, lasts longer than batteries, less polluting to dispose of
cons
-H is a gas, takes up more storage space than fossil fuels or batteries
-explosive when mixed w/ air
-process to make it comes from en. from fossil fuels, counter-prod.
complete the reversible reaction:
hydrated copper sulfate (blue) <—–> anhydrous….. + …
-copper sulfate
+ water
equilibrium lies to the left if there are more ……. and when it lies on right there are more ……..
-reactants
-products
state la chatelier’s principle
change the conditions of a reversible reaction
position of equilibrium will shift to try and counteract change
(in sealed system)
when you inc temp in an equilibrium reaction, the position moves in the ……. direction to ………….
when you decr. temp, the position moves in the …. direction to ……..
-endo direction to decr. temp again
-exo direction to inc temp by releasing more energy
if pressure inc in and equilibrium system, the position will shift to the side ……….
if pressure decr in and equilibrium system, the position will shift to the side ……….
-with the least molecules to inc decr pressure
-with most molecules to incr pressure
finish the reaction:
magnesium + hydrochloric acid ->
magnesium chloride + hydrogen
What is collision theory:
-chem reactions can only happen if reactant particles collide with sufficient energy
-rate determined by frequency of collisions
