RATES AND EQUILLIBRIUM Flashcards
How do you calculate the rate of reaction?
Volume of gas / time.
What is the collision theory?
For a chemical reaction to occur, reactant particles must collide.
The particles must have enough energy for the collision to be successful by producing a reaction.
The rate of reactions depends of the rate of successful collisions.
The more successful collision the faster the reaction.
What factors effect the rate of reaction?
Varying temperature. Varying concentration. Varying the pressure. Changing surface area. Adding a catalyst.
How does concentration(or pressure) affect the rate of a reaction?
More concentrated a solution.
The more particles there are the reactants in a given volume.
More often there are collisions or greater chance of collisions with other reactants.
Leading to a faster reaction.
How does surface area affect the rate of reactions?
If the solid splits into smaller pieces the surface area increases.
This means that there is an increased area for the reactant particles to collide with.
The smaller the pieces, the larger the surface area.
More collisions greater chance of reaction.
How does a catalyst affect the rate of a reaction?
Speed up the rate of the reaction.
Catalysts are specific, a substance that speeds up the rate of reaction.
- by taking an alternative route
- lowers the activation energy needed for the reaction
- catalyst is reused as it does not take part in the reaction.
The catalyst is chemically unchanged
You have the same mass of the catalyst at the end as you did at the start.
Highly specific.
What type of reaction is a forward reaction?
Endothermic.
What type of reaction is a backward reaction?
Exothermic.
What is a reversible reaction?
The products of the reaction can react to form the reactants.
What happens when a reaction is at equilibrium?
At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction.
The reactants are making products at the same rate as the products are making reactants.
Talk about what happens in a reversible reaction?
As the concentration of the products build up, the rate at which they react to re-form reactant increases. As this starts to happen, the rate of the forward reaction is decreasing. That is because the concentration of reactants is decreasing from its original maximum value. Eventually, both forward and reverse reactions are happening at the same rate, but in opposite directions.
What happens if you increase the concentration of a reactant?
The position of the equilibrium will shift to the right, if favour of the products in order to reduce the concentration of that reactant.
What happens if the forward reaction produces more molecules of gas
An increase in pressure decreases the amount of products formed.
A decrease in pressure increases the amount of products formed.
What happens if the forward reaction produces fewer molecules of gas?
An increase in pressure increases the amount of products formed.
A decrease in pressure decreases the amount of products formed.
What happens if the forward reaction is exothermic?
An increase in temperature decreases the amount of products formed.
A decrease in temperature increases the amount of products formed.
