Rate of Reaction Flashcards
what is the rate of a reaction
the change in the concentration of the product or reactant over unit time
how is the volume of gas given off in the ‘volume of gas given off’ method measured with
a gas syringe
How can you find the rate of reaction from a graph?
The gradient
What is the relationship between rate and time?
They are inversely proportional; the faster the rate the shorter the time
What does collision theory state?
That reactions can only occur if particles collide.
The particles must collide with enough energy to react
The particles must collide with the correct orientation
Activation Energy
thethe minimum energy required for substances to break tthe bond in the reactant anf enale paraticles to form products
4 factors that affect rates of reaction
Temperature
Concentration of solutions
Surface area of solids
Using a catalyst
How does surface area increase the rate of reaction?
(small particle= large SA) Increasing the SA, exposes more of the surface. This means more frequent collisions in the same time and this increases the rate of reaction.
How does temperature effect the rate of reaction?
Temperature increases the speed of the particles, so they collide more often and with more energy. They also reach the activation energy required much quicker. This increases the rate of reaction
The rate is not directly proportional to temperature
Roughly by how much will the rate of reaction will increase by if the temperature is increased by 10 degrees?
Double
How does the concentration effect the rate of reaction?
A higher concentration means more particles are dissolved in the same volume, meaning the particles are closer together and so collide more often
The rate of reaction is directly proptioanl to the concentration
what is a cataylst
A catalyst is a substance which alter the rate or reaction of a chemical
How do catalysts work?
They lower the activation energy as they provide an alternative pathway at a lower energy level so more successful collisions occur ^^ meaning they speed up reactions
what is a endothermic reaction
a reaction which takes in energy from the surroundings, usually in the form of heat and is usually shown by a fall in temperature of the surroundings
what would happen if the energy input is less than the activation energy
there wont be enough energy to start a reaction, so nothing would happen
what is an exothermic reaction
a reaction which gives out energy to its surroundings, usually in the form of heat and usually shown by a rise in temperature of the surroundings
