Rates of Reaction Flashcards
In order for a chemical reaction to occur, what must occur between the reactants?
The reactant particles must collide with sufficient force and at the correct orientation/angle
Why is a chemical reaction occur quickly at the beginning?
There are more reactant particles per ml available to collide therefore there are more successful collisions per second
What does the speed of a chemical reaction slow down over time?
Most of the reactant particles have already collided to form new products and so less reactant particles per ml are available to collide so there are less successful collisions per second.
Would 5g of calcium carbonate powder or a 5g chip of calcium carbonate produce more carbon dioxide when both are added to 20ml of HCl?
Neither because more the chip and the powder have the same mass and therefore the same number of reactant particles. They are both added to the same number of acid particles so therefore the total number of collision is the same.
Would 5g of calcium carbonate powder or a 5g chip of calcium carbonate react faster when both are added to 20ml of HCl and why?
The powder would react faster because it has a greater surface area. This means there are more calcium carbonate particles available to collide with the acid particles so there are more successful collisions per second.
If the temperature of the reactants is increased, explain what happens to the rate of a reaction.
The rate of reaction would increase because the reactant particles have more energy. This makes them move around faster leading to more successful collisions per second.
If the concentration of a reactant is decreased, explain what would happen to the rate of a reaction.
The rate of reaction would decrease because there would be less particles per ml available to collide so less successful collisions per second.
What effect does a catalyst have on the rate of a reaction?
It increases the rate of a reaction by lowering the energy needed for the reaction to occur because it causes more frequent collisions between the reactant particles.
