rates of reaction Flashcards
(14 cards)
what is a rate of chemical reaction
how fast reactants are changed into products
give examples of a slow moderate speed and fast reaction
slow- rusting
moderate speed- magnesium + acid
fast- burning/explosions
how can you calculate the speed of a reaction
amount of product formed x used / time
on a graph, the steeper the line the faster the rate of reaction. overtime the line becomes less steep what does this indicate
the reactants are used up
what is the collision theory
particles must collide with enough energy in order to react
what is collision frequency
how often the particles collide. the more collisions there are, the faster the reaction
what is the rate of chemical reaction dependent on
collision frequency
energy transferred during a collision
what is the minimum amount of energy that particles need to react called
activation energy
why do particles need activation energy
to break the bonds in order to react and start the reaction
what factors increase the number of collisions in a reaction
the amount of energy particles that collide. an increase in the number of collisions increases the rate of reaction
name four things that affect the rate of reaction
- temperature
- concentration of a solution/pressure of gas
- surface area
- presence of a catalyst
what happens when the temperature is increased in a reaction
when the temperature is increased, the particles have more energy and move faster so have more collisions
what happens when the concentration or pressure is increased in a reaction
if a solution/gas is more concentrated, it means there are more particles of reactant in the same volume so collisions are more likely so the reaction rate increases
what happens when the surface area is increased in a reaction
the rate of reaction increase if one reactant is solid and breaks into smaller pieces therefore increases its surface area so the surface area to volume ratio is increased
