6. Rates of reaction Flashcards
What is the rate of a chemical reaction?
How quickly the reactants in a reaction are used up
What is the formula for a mean rate of reaction?
quantity of reactant used OR product formed/time taken
What are the two possible units for rate of reaction?
g/s or cm3/s (where s is seconds)
What is “collision theory”?
Reactions only occur when particles collide with enough energy in the correct orientation
What is the activation energy?
The minimum amount of energy a particle needs to react
What factors can increase the rate of a reaction?
Increasing temperature, increasing surface area of a solid, increasing concentration in solution, increasing pressure of gases
Explain why increasing the surface area increases the rate of a reaction
More particles are available to collide, there are therefore more frequent collisions between reactants.
Explain why increasing the concentration increases the rate of reaction
More particles in the same volume, therefore more frequent collisions
Explain why increasing the pressure of a gas increases the rate of a reaction
More particles in the same volume, therefore more frequent collisions
Explain why increasing the temperature increases the rate of reaction
Increases the kinetic energy of particles so more have the activation energy, more frequent collisions.
What is a catalyst?
Something which speeds up the rate of a reaction but is not used up itself
What chemical symbol represents a reversible reaction?
?
If a reaction is exothermic in the forward direction what will it be in the reverse direction?
Endothermic
What is equilibrium?
The point in a reversible reaction when the forward and reverse reactions are occurring at the same rate
What is Le Chatelier’s principle?
When the conditions of a reaction at equilibrium is changed, it will seek to counteract that change
