Rates of Reaction Flashcards
Name the four factors that affect the rate of reaction
Temperature
Concentration
Particle size
Use of a catalyst
What must happen for a reaction to occur?
For a reaction to occur, the particles that are reacting must collide with each other
Only some of all the collisions that take place cause a chemical change to happen. What is the name given to this?
These are called ‘successful’ collisions. The greater the number of ‘successful’ collisions, the faster the rate of a reaction. This is known as the ‘collision theory’.
Describe what will happen to the particles in a reaction if the temperature is increased
If the temperature is increased, the particles have more energy and so move quicker. Increasing the temperature increases the rate of reaction because the particles collide more often and with more energy. The higher the temperature, the faster the rate of a reaction will be.
What will happen in a reaction between hydrochloric acid and calcium carbonate if the temperature is increased?
An increase in temperature leads to an increase in the speed of release of carbon dioxide, but not the total volume of carbon dioxide released.
What will happen if the concentration of reactants is increased?
If the concentration of reactants is increased, there are more reactant particles moving together. There will be more collisions and so the reaction rate is increased. The higher the concentration of reactants, the faster the rate of a reaction will be.
What will happen if the particle size of a reactant is decreased?
By decreasing the particle size of a reactant, we are increasing its surface area. The greater the surface area, the higher the chance of collisions, so the faster the rate of reaction. The smaller the particle size the faster the reaction.
What is the rate of a chemical reaction a measure of?
The rate of a chemical reaction is a measure of how fast the reactants are being used up and how fast the products are being made.
How could you determine the rate of reaction?
You could determine the rate of reaction by measuring:
- changes in the concentration of the reactants or products
- changes in the mass of the reactants or products
- changes in the volume of the reactants or products
State the equation which can be used to calculate the rate of reaction
Rate of Reaction= Change in quantity / Change in time
Describe a rate of reaction graph with a fast reaction
A rate of reaction graph with a fast reaction would have a steep slope, this could be because it has a higher temperature, a higher concentration or because the reactant is in small pieces
Describe a rate of reaction graph with a slow reaction
A rate of reaction graph with a slow reaction would have a less steep slope, this could be because it has a lower temperature, a lower concentration or because the reactant is in larger pieces
Describe a rate of reaction graph once it goes flat
When the reaction is finished the graph goes flat as no more products are being produced.
