Rates Of Reaction Flashcards
(112 cards)
Reactions can go at all sorts of different
Rates
What is the rate of a chemical reaction?
The rate of a chemical reaction is how fast the reactants are changed into products.
Examples of slow reactions
The rusting of iron Chemical weathering (acid rain damage to limestone buildings)
Example of a moderate speed reaction
Metal magnesium reacting with an acid to produce a gentle stream of bubbles
Burning is a ____ reaction.
Fast reaction. But explosions are even faster and release a lot of gas. Explosive reactions are all over in a fraction of a second.
How can you find the speed of a reaction
Recording the amount of product formed or the amount of reactant used over time
Rate of reaction - the steeper the line on the graph
The faster the rate of reaction. Over time the line becomes less steep as the reactants are used up.
The quickest reactions have the steepest lines and
Become flat in the least time as the reactants are used up
Particles must collide with ________ in order to react
Enough energy
Reaction rates are explained perfectly by the
Collision theory
Collision theory
The rate of chemical reaction depends on- The collision frequency of reacting particles (how often they collide) More collisions, faster reaction
The energy transferred during a collision. Particles need to collide with enough energy for the collision to be successful
Activation energy
The minimum amount of energy particles need to react. Particles need this energy to break the bonds in the reactants and start the reaction.
What will increase the rate of reaction
Factors that increase the number of collisions (So a greater proportion of reaction particles collide) or the amount of energy particles collide with will increase the rate of the reaction.
Which 4 things does the rate of reaction depend on?
Temperature
Concentration of solution or pressure of gas
Surface area (changes depending on the size of the lumps of a solid)
Presence of a catalyst
More collisions increase the
Rate of reaction
All four methods of increasing the rate of a reaction can be explain in terms of
Increasing the number of successful collisions between reacting particles
Increasing the temp
Increases the rate
When temperature is increased
The particles all move faster
If the particles are moving faster
They are going to collide more frequently
Also the faster the particles move the more energy they have
So more of the collisions will have enough energy to make the reaction happen
Increasing the conc or pressure
Increases the rate
If a solution is more concentrated
It means there are more particles in the same volume of water (or other solvent)
When the pressure of a gas is increased
It means that the same number of particles occupies a smaller space. This makes collisions between the reactant particles more frequent
Increasing the SA
Increases the rate