Rates of reactions Flashcards
Define rate of reaction.
The rate of which a chemical reaction is how fast the reactants are changed into products.
how can you find the speed of a reaction?
By recording the product formed or the amount of reactant used up over time.
what does the rate of a chemical reaction depend on?
Collision frequency of particles (how often they collide). The more collisions there are the faster the reaction.
The energy Transferred during a collision. Particles have to collide with enough energy for the collision to be successful.
what term is used to describe the minimum amount of energy that particles need to react?
Activation energy
what 4 things do a rate of reaction depend on?
1) Temperature
2) concentration of a solution or pressure of gas
3) Surface area
4) presence of a catalyst
what happens to all the particles when the temperature is increased during a reaction.?
The particles move faster and therefore colliding more frequently speeding up rate of reaction.
what affect does increasing the concentration or pressure have on the rate of reaction?
It increases the reaction. When it is more concentrated which means there are more particles.
when the pressure of gas is increased the same number of particles occupies a smaller space
making collisions more frequent
how does increasing surface area increase rate of reaction?
If one of the reactants is a solid then breaking it up into smaller pieces will increase surface area to volume ratio.
The same volume of solid will encounter more collisions.
How does using a catalyst increase rates of reaction?
As a catalyst is something that speeds up reactions, they decrease the activation energy needed for the reaction to occur.
How do you calculate mean reaction rate from a graph?
mean rate of reaction = change in y / change in x
