Chemistry Topic 6 Flashcards
What is rate of reaction?
How fast the reactants are changed into products
Example of slow reaction and fast reaction:
Slow- Rusting of metal
Fast- explosion
How does temperature affect rate of reaction?
The higher the temperature, the faster the reaction
How does concentration ( pressure of gasses) affect rate of reaction?
The more the concentration, the faster the reaction
How does surface area affect the rate of reaction?
The larger the surface area, the faster the reaction
How does catalysts affect the rate of reaction?
A catalyst speeds up the reaction
What two things does the collision theory say the rate of reactions depends o?
- depends on the collision frequency
- energy transferred during the collision (has to have enough energy to be successful)
What are ways to increase frequency of collisions:
- increase temp (increase energy)
- increasing concentration/pressure
- increasing surface area (creates small pieces)
How to increase energy of collisions:
increase the temperature
What is the name for the minimum amount of energy needed in order for particles to react?
Activation energy
The rate of reactions is directly proportional to…
Frequency of successful collisions
What is a catalyst?
A substance that speeds up a reaction without being changed or being used up in the reaction
What are biological catalysts known as?
Enzymes
How do catalysts speed up a reaction?
By decreasing the activation energy
What is the formula for mean rate of reaction?
Quantity of reactant used (product formed) / time
How to use precipitation to measure the formation of product?
If initial reaction is transparent, and the product is a precipitate (turns opaque), then you can measure how long it takes for a mark to disappear
How do you measure the formation of product?
Precipitation change in mass / volume of gas given off
What is a reversible reaction?
One where the products of the reactions can react to produce the original reactants
Reversible reaction equation:
A + B ⇌ C + D
What is equilibrium?
Where the amounts of of reactants and products reach a balance
When is equilibrium reached?
In a reversible reaction in a closed system
What must be true for equilibrium to lie on the right?
The concentration of products is greater than that of reactants
What must be true for equilibrium to lie on the left?
The concentration of reactants is greater than that of the products
In reversible reactions if it is exothermic in one direction it is…
Endothermic in the other direction
