C6 the rate and extent of chemical change Flashcards
how do you calculate the rate of reaction?
amount of reactant used / time
or
amount of product formed / time
how do you find the rate of reaction graphically?
-draw tangents on the graph
-calculate the gradient of the tangents
on this kind of graph x-axis is time and y-axis is (amount of products or reactants)
list some factors which effect the rate of reaction (5)
concentration
pressure
temperature
surface area
catalyst
what is collision theory
chemical reactions can only occur when reacting particles collide with each other with sufficient energy
what changes when reversing a reversible reaction
if its endothermic one way it’ll be exothermic the other way and vice versa
what is equilibrium
reactions act at the exact same rate in both directions
what is Le Chateliers principle
when a change is made to the the system and its at equilibrium it will change to counteract the change until its at equilibrium again
what happens when the concentration of a reactants is increased from equilibrium.
Reaction shifts so that more products are produced until in equilibrium again.
what happens when the concentration of products is increased from equilibrium
Reaction shifts so that more reactants are produced until in equilibrium again.
What are some units we could use for rate of reaction?
grams or cm^3 or moles
PER SECOND
How can we explain how temperature/pressure/concentration/surface area increase rate of reaction using collision theory?
Increase the frequency of collisions of reactants and/or makes collisions more energetic. So rate of reaction is increased.
What is a catalyst?
Substance that speeds up a chemical reaction without being used up.
Catalysts decrease activation energy for a reaction.
Enzymes act as catalyst in biological reactions.
what effect does increasing temperature have on the equilibrium
the equilibrium will move towards the endothermic reaction because endothermic reactions require energy which the reaction now has more of
what effect does decreasing temperature have on the equilibrium
the equilibrium will move towards the exothermic reaction because it doesn’t have enough energy to perform endothermic reactions
how does increasing pressure effect the equilibrium
it will go towards the side where least molecules are made
