2- Rates And Energy Flashcards
What is collision theory?
He theory that reactions can only happen if particles collide (enough to cause activation energy)
What are the five ways you find the rate of reaction?
ROR= amount of reactant used/time
ROR= amount of product produced/time
Time taken for a certain amount of solid to appear
Time taken for a certain amount of gas to be collected
The gradient of the graph
What is activation energy?
The minimum energy ended for particles to react
What are the factors that increase the chance of collision or amount of energy in particles
Increasing the: temperature, concentration of solutions, pressure of gasses, surface area of solids
Using a catalyst
What is a catalyst?
A substance that speeds up a chemical reaction and remains unchanged throughout the reaction
How do you increase the surface area of a solid?
Break it up into smaller pieces (even fine powder)
How do temperatures effect the reaction?
Increases the speed and amount of energy of the particles, meaning they collide more often
How does increasing the concentration effect the rate of reaction?
There are more particles in the same volume (amount of space) meaning they are more likely to collide - they collide more often which increases the rate of reaction
How does a catalyst effect a rate of reaction?
They lower the activation energy needed by the particles so more of the collisions result in a reaction - speeding up the rate of reaction
Why are catalysts used so much?
They conserve resources because less activation energy is needed. They also can be re-used over and over again which saves money and the environment
What is generally used as a catalyst and what two things are promising catalysts for the future?
Transition metals (toxic) are used now Nanoparticles and enzymes could be more effective in the future
What is an endothermic reaction?
A reaction that takes energy from the surroundings
What is an exothermic reaction? Give three examples
A reaction that gives out energy to the surroundings
Combustion
Oxidation
Neutralisation
What is thermal decomposition?
The breakdown of compounds by heat
What happens in a reversible reaction in terms of energy?
The forward and reverse reaction involve equal energy. One direction has to be endothermic and the other exothermic. The endothermic will take in the same amount the exothermic will release
