THE RATE AND EXTENT OF CHEMICAL CHANGE Flashcards
The steeper the line on the graph the ……… the rate of reaction
faster
the quickest reactions have the _______ lines and become flat in the _______ time
steep and least
the more collisions there are…..
the faster the rate of reaction
particles have to collide with __________ for the collision to be successful
enough energy
what is activation energy
the minimum amount of energy that particles need to react
name 4 things that the rate of reaction depends on
temperature
the concentration of solution or pressure of gas
surface area
catalysts
increasing the temperature……
increases the rate of reaction
why does increasing the temperature, increase the rate of reaction
the higher the temperature, the faster the rate of reaction because particles have more energy, so can therefore move around faster, this will lead to more frequent successful collisions
why does increasing the pressure or concentration increase the rate of reaction
the higher the pressure/concentration the faster the rate of reaction will be this Is because there are more particles in a fixed volume so there is a higher chance of a successful collision
why does increasing the surface area increase the rate of reaction
it increases the rate of reaction because there are more particles available to react, leading to more frequent successful collisions
do catalysts get used up in the reaction themselves
no catalysts do not get used up in the reaction
what is a catalysts and what does it do
catalysts speed up the rate of reaction by providing an alternative reaction pathway with a lower activation energy
how do you find out the mean reaction rate on a graph
you find the overall change in y value and then divide it by the time taken for the whole reaction
how do you find the rate of reaction at a particular point
draw a tangent to the curve (at the point you want)
then work out the gradient of the tangent
reversible reactions will reach…..
equilibrium
what is a closed system
when no reactants or products can enter or escape
if the equilibrium lies to the right the concentration of products is ___________ than that of the reactants
greater
if the equilibrium lies to the left, the concentration of reactants is _________ than that of the products`
greater
what does the position of equilibrium depend on
the temperature
the pressure
the concentration
what does it mean if a system is at equilibrium
a system is at equilibrium when both the forward and backward reactions are happening at the same rate
what is le chateliers principle
if you change the conditions of a reversible reaction at equilibrium, the system will try to counteract this change
what happens if you decrease the temperature (equilibrium)
the position of equilibrium shifts in the exothermic direction. There is an increase in products of the exothermic reaction and there is an decrease in products in the endothermic reaction
what happens if you increase the temperature (equilibrium)
the position of equilibrium shifts in the endothermic direction. There is an increase in products of endothermic reaction and there is a decrease in products of the exothermic reaction
what happens if you increase the pressure (equilibrium)
if you increase the pressure equilibrium shifts in the direction where there are fewer molecules of gas
what happens if you decrease the pressure (equilibrium)
if you decrease the pressure equilibrium shifts in the direction where more molecules of gas
what happens if you increase the concentration of the reactants(equilibrium)
the system tries to decrease it by making more products
what happens if you decrease the concentration of the products (equilibrium)
the system tries to increase it again by reducing the amount of reactants
