C2-4 Rates And Energy Flashcards
What does the collision theory state?
That reactions can only happen if particles collide.
How can the rate of reaction be found?
By finding out how much reactant was used or how much product was made over time.
What is the activation energy?
The minimum energy particles need to collide and change into new substances(react).
What are the factors that will increase the rate of reaction?
Temperature, concentration of solutions, pressure of gasses, surface area of solids, using a catalyst
Why does a powder react faster than large pieces of solid?
Smaller pieces exposes more surface increasing the surface area meaning that more particles collide at the same time.
Why does increasing. The temperature increase the rate of reaction?
Particles collide more frequently and energetically meaning that many particles have more energy than the activation energy required.
What increases the rate of reaction by making particles be closer together causing them to collide more frequently?
Increasing the concentration or pressure.
How do catalysts speed up reactions?
They lower the activation energy meaning that more collisions result in a reaction.
Are catalysts used up during a reaction?
No, they are left at the end of the reaction and they can be used over and over again.
Why are catalysts used in industry?
They can reduce the energy and time needed to carry on reactions and they are very cheap as they rarely need replacing.
What are reactions that transfer energy to its surroundings called?
Exothermic
What do endothermic reactions do?
Take in energy from their surroundings.
What do thermal decomposition reactions need to keep on going?
To be constantly heated
If a reversible reaction is endothermic in one way, in the oposite way it must be…
Exothermic(release the same energy taken in)
What can exothermic changes be used for?
Hand warmers and self heating cans etc
