Monitoring & Controlling Chemical Reactions Flashcards
(24 cards)
calculation for rate of reaction
reactant used or product formed / time taken
what type of flask is used to measure mass
open flask
how do you measure the rate a precipitate forms?
mixing two solutions over an X and timing how long it takes to disappear
what is a disadvantage of measuring the rate a precipitate forms?
people may disagree on the time it took for the X to disappear
what is the relationship between the rate of reaction and the reaction time
inversely proportional
how to calculate the rate of reaction at a particular point?
- find the gradient
- draw a tangent
name factors that affect the rate of reaction
1 concentration
2 temperature
3 surface area
4 catalyst
what is the advantage of increasing concentration / temperature?
the rate of reaction will increase as the line on the graph is steeper
what is the collision theory?
particles must collide before a reaction takes place by using activation energy
what does rate of reaction mean?
the number of collisions between reactant particles every second
why does the rate of reaction increase when the concentration increases?
there are more reactant particles in the give volume meaning more frequent and successful collisions per second
what are catalysts?
substances which speed up the rate of reaction without themselves being altered
give an example of a catalyst
iron used to catalyse the Haber Process for the production of ammonia
What is the point of using a catalyst?
they lower the activation energy and provide an alternative pathway that requires less energy
what are enzymes?
biological catalysts
give an example of a use of an enzyme?
lower temperatures and pressures in reactions saving energy and money
what are reversible reactions?
when a reaction occurs in both directions
what does dynamic equilibrium mean?
in a closed system the rate of the forward reaction is equal to the rate of the backward reaction
what is an example of dynamic equilibrium
treadmill and walking down the up escalator
what conditions need to be present for dynamic equilibrium to take place
a closed system and a constant concentration
what is Le Chatelier’s Principle
when a change is made to the conditions of a system at equilibrium, the system automatically moves to oppose the change
how do you increase the percentage yield using Le Chatelier’s Principle
move the equilibrium to the product side which increases the concentration product at the point of dynamic equilibrium
how does an increase in temperature effect the equilibrium position?
equilibrium moves in an endothermic direction to reverse the change
how does a decrease in pressure effect the equilibrium position?
equilibrium moves in the direction where a larger gas is being produced to increase the pressure again
