Topic #6: The Rate and Extent of Chemical Change Flashcards
What are the two equations for calculating rate of reaction?
Quantity of product formed / Time taken
Quantity of reactant used / Time taken
How do we calculate the mean rate of reaction at a certain point?
Draw a tangent of the graph, then do difference in y / difference in x
What are the 5 things that affect the rate of reaction, and how so?
Temperature - the higher the temperature, the higher the rate
Concentration of reactants - increased concentration - increased rate
Catalysts - Catalysts speed up reactions
Pressure of the gases - higher pressure, higher rate
Surface area - larger surface area, increased rate
What is the collision theory for activation energy?
Reactions can only begin when enough particles collide with sufficient energy
How do catalysts speed up reactions?
They reduce the amount of energy that is needed to start the reaction
Are they used up in reactions?
No
What does the reversible reaction arrow look like?
Half an arrow point left, half pointing right, on top of each other
When reactions are reversed is their endo/exo-thermic trait reversed too?
Yes
What is equilibrium?
When the forward and backwards happen at the same time (no products or reactants are escaping)
What is Le Chatilier’s Principle?
That when a system changes, a anew equilibrium will be reached
How does changing concentration affect the equilibrium?
Increase - more product
Decrease - less product
How does temperature affect the equilibrium?
increased - products increase for an endothermic reaction, products decrease for an exothermic reaction.
decreased - products decrease for an endothermic reaction, products increase for an exothermic reaction
How does a pressure change affect the equilibrium?
increase - equilibrium shifts towards side with smaller molecules
decrease - equilibrium shifts towards the side with larger molecules
