Rates and Equilibrium Flashcards
What are the two ways that the rate of reaction can be measured
Amount of product used up over time
Amount of reactant used up over time
If we have a graph with amount of product or reactant used up over time, with a curve of best fit, how can we measure the rate of reaction at a given time
Measure the gradient by drawing a tangent to the curve at that point
What does the collision theory state
Particles must collide with a minimum amount of energy before they can react with each other
What is the minimum amount of energy that particles must react with called
Activation energy
What happens to the rate of reaction if the surface area to volume ratio of any solid reactants increases
The rate of reaction increases
What is the effect on the rate of reaction if the temperature is increased, and why
The rate of reaction increases because:
the particles collide more frequently, due to the added kinetic energy
the particles collide with more energy
What is the effect of increasing the concentration of reactants in a solution
Rate of reaction increases because the particles will collide more frequently
What is the effect of decreasing the pressure in a gas
The rate of reaction decreases as the gas particles react less frequently
What is a catalyst
A substance which speeds up the rate of reaction, without being used up, by providing an alternate reaction pathway
What happens to the activation energy of a reaction when a catalyst is used
The activation energy is lowered
What are some advantages of catalysts in industry
- cheaper to use a catalyst than pay for the extra energy needed without one, helping the environment
What is a reversible reaction
A reaction where the products formed can react to make the original reactants
What symbol is used in a reversible reaction
⇌
True or False: both reactions in a reversible reaction are exothermic
False - One reaction is endothermic and one is exothermic
Define equilibrium
Thee state of a reaction where the rate of the forward reaction equals the rate of the reverse reaction, in a closed system
Explain how a reversible reaction reaches equilibrium
Initially, only the forward reaction occurs because there are no products formed yet
The rate of the backwards reaction increases, but is still lower than the rate of the forward reaction because there are less products
The rate of the backwards reaction gradually becomes higher than the rate of the forward reaction as there are fewer reactions now
This process continues until the rate of the forwards and backwards reactions are equal
What does Le Chatelier’s principle state
If an external condition is introduced to a reversible reaction at equilibrium, the equilibrium will shift to cancel out that change
What is the structure used to answer a rate of reactions question
Shift Favour Why
What reaction in a reversible reaction does equilibrium favour if the temperature increases
The endothermic direction is favoured
What reaction in a reversible reaction does equilibrium favour if the pressure increases
The reaction which produces the least amount of products
