How Fast? Chemistry Checklist Flashcards
Recall a definition for rate of reaction
how quickly a product is formed or how quickly a reactant is used up over time
Explain how there can be different units for measuring rate of reaction
because different experiments have different methods
List some factors that can affect the rate of a chemical reaction
-temperature
-surface area
-concentration
-pressure
-use of catalysts
What is collision theory?
states that chemical reactions occur only when the reactant particles collide with sufficient energy to react - activation energy
What is activation energy?
the minimum amount of energy required by reacting particles for a successful collision to occur
Describe how temperature affects the rate of reaction.
When you increase the temperature, the rate of reaction increases because increasing the temperature raises the energy and speed of the particles.
Use collision theory to explain how temperature alters the rate of reaction.
Increasing the temperature gives the particles more energy and so move faster resulting in more frequent collisions between particles. Particles have greater energy than the activation energy so their will be a creater percentage of successful collisions.
Describe how surface area of a solid can be increased
Cutting it up or grinding it into powder
Describe how changing the surface area changes the rate of reaction
Increasing the surface area increases the rate of reaction.
State how collision theory explains the effect of surface area on the rate of reaction.
Collision theory states that particles need to have successful collisions in order to react. Increasing the surface area increases the rate of reaction. This is because more particles are exposed which leads to more frequent collisions
Calculate surface area to volume ratio
surface area:volume.
Describe how changing concentration affects the rate of reaction
When you increase concentration, the rate of reaction increases
Use collision theory to explain how changing the concentration alters the rate of reaction
Increasing the concentration increases the rate of reaction. This is because there are more reacting particles in the same space which increases the chance of successful collisions.
Describe how changing pressure of gaseous reactants affects the rate of reaction.
Increasing the pressure increases the rate of reaction.
Use collision theory to explain how changing the pressure alters the rate of reaction
Increasing the pressure increases the rate of reaction. This is because there are more reacting particles in the same space which increases the chance of successful collisions.
Describe what the activation energy of a reaction is
The minimum amount of energy required for two reactant colliding particles to create a successful collision
State what is a catalyst
A catalyst is a substance that lowers the activation energy without being used up
Explain how a catalyst affects the rate of a reaction
Using a catalyst will increase the rate of a reaction. This is because it lowers the activation energy so more collisions result in a reaction
What is an independent variable?
The thing you want to change
What is a dependent variable?
The variable that is affected by the independent variable - is dependent on the independent variable
What is a control variable?
The variable that is kept the same- constant
What is a continuous variable?
a variable whose value is obtained by measuring. eg. height
What is a categoric variable?
a characteristic that can’t be quantifiable. eg. hair colour
