Unit 2: 4 - Rates and Energy Flashcards
How do we work out the rate of reaction?
Amount of reactant used / Time OR Amount of product formed / Time
What it the rate of reaction?
The speed of the reaction.
How can we find the rate of reaction on a graph?
It is the gradient.
What is collision theory?
Collision theory states that reactions can only happen if particles collide.
What is activation energy?
The minimum energy that particles need to react.
Name 5 ways of increasing the rate of reaction (by increasing the chance of collision).
Increasing the: -Temperature -Concentration of solutions -Pressure of gases -Surface area of solids And using a catalyst.
Why do powders react faster than large pieces of a solid?
Because the surface area is much larger.
Why does temperature effect the amount of collisions?
As the particles vibrate more and move faster, they collide more often.
What is an exothermic reaction?
A reaction that gives out heat.
What is an endothermic reaction?
A reaction that takes in heat?
Give 3 examples of exothermic reactions.
- Combustion
- Oxidation reactions (e.g. Respiration)
- Neutralisation reactions.
Give an example of an endothermic reaction.
Thermal decomposition
A reversible reaction has what differences on each side?
One side is exothermic and one side is endothermic.
Give examples of common uses of an exothermic and an endothermic reaction.
Hand warmers and ice packs.
