C8 Flashcards
what’s the collision theory
the more collisions the higher the chance of particles colliding in the correct orientation which increases the rate of reaction
what is the rate of reaction
how much of the product is made each second
what are the 2 ways to measure the rate of a reaction
the rate at which a reactant is used up
the rate at which a product is made
how does the speed of a reaction change as it progresses
a reaction is fastest at the start but then decreases and is slowest at the end
what effects the rate of a reactant
temperature, concentration/pressure of a gas, surface area and catalysts
whats needed for a chemical reaction to occur
-the activation energy
-the correct orientation in which particles need to collide
what is a precipitate
an insoluble solid which makes a solute go cloudy
what are the different ways in which you can measure the rate of a reaction happening
- testing the levels of light being able to pass through the solute
- testing how fast a product is made
- testing how fast a reactant is used up
what is a limiting reactant
a reactant that is not in excess and is completely used up by the end of the reaction
what effects the rate of a chemical reaction
temperature
surface area
catalysts
concentration/pressure
how does temperature affect the rate of a chemical reaction
temperature affects the rate at which collisions happen which means more of these collisions have the activation energy so the rate of reaction is faster
how does increasing the concentration affect the rate of a chemical reaction
increasing the concentration means increasing the amount of particles in a volume which increases the amount of collisions that happens per second and so increase the rate of reaction
how does increasing the surface area affect the rate of a reaction
increasing the surface area means that you’re increasing the surface area : volume ratio which means there’ll be more frequent collisions so the rate of reaction will be faster
what is a catalyst
a substance which increase the rate of a reaction without being used up or chemically changed.
how do catalysts work
they reduce the activation energy of a reaction by giving an alternate route for the reaction to take place
what do catalysts do in a car exhaust
platinum helps convert carbon monoxide and nitrogen oxide into nitrogen and carbon dioxide
what do catalysts do in a car exhaust
platinum helps convert carbon monoxide and nitrogen oxide into nitrogen and carbon dioxide
what are reversible reactions
reactions in which the products turn into the reactants but the reactants can turn into the products 2
how much joules is needed if 330J of energy is required for the forward reaction
330J as the amount of energy for the forward reaction is always the same as the backward reaction
if one of the reaction is endothermic in one direction then what is the type of reaction in the other direction
exothermic
what is dynamic equilibrium
the rate of the forward reaction is the same as the rate of the backward reaction
what is le chateliers principle
whenever a change in the equilibrium occurs, the position of the equilibrium changes to cancel out the change
if you increase the pressure in a reaction what will happen
the equilibrium will shift to the the side of the reaction with less gas which can be found from looking at the number in front of molecules. e.g 6H = 6 hydrogen
if you increase the temperature of a reaction what will happen
the equilibrium will shift to the side which favours the endothermic reaction
when can dynamic equilibrium be achieved
when its in an enclosed system where no reactants or products can get in or out
