Module Five: Equilibrium and Acid Reactions Flashcards
(40 cards)
If the Gibbs free energy is negative…
the reaction will go in the forward direction and is spontaneous
If the Gibbs free energy is positive…
the reaction will go in the reverse reaction and will not be spontaneous
If the Gibbs free energy is equal to zero..
the reaction is at equilibrium
What is equilibrium
The point in a reversible reaction where there is no change in concentration of products and reactants.
If a reaction lies to the left…
the reactants have a higher concentration
What is Le Chatelier’s Principle?
“If a system at equilibrium is subject to change in conditions, then the system will behave in such a way as to partially counteract the imposed change”
What will happen to a system at equilibrium if the concentration of reactant(s) is increased?
Forward reaction will be favoured.
Reaction would shift to the right.
Increase in concentration of products, decrease in concentration of reactants.
What will happen to a system at equilibrium if the concentration of products increases
Reverse reaction will be favoured, reaction would shift to the left, increased concentration of reactants, decreased concentration of products.
What will happen to a system at equilibrium if pressure increases (volume decreases) ?
The reaction which is responsible for producing the least amount of gaseous molecules will be favoured.
What will happen to a system at equilibrium if pressure decreases (volume increases) ?
The reaction which is responsible for producing the most amount of gaseous molecules will be favoured.
What will happen to a system at equilibrium if temperature is increased?
The endothermic reaction will be favoured to absorb the excess heat.
What will happen to a system at equilibrium if temperature is decreased?
The exothermic reaction will be favoured as a way to increase the temperature of the system.
How does a catalyst affect a system at equilibrium?
it will only increase the reaction rate of the forward and reverse reactions. It will not change it’s position or concentration.
What five questions can we use to predict a change of equilibrium?
1) what change was imposed?
2) what is the opposite of this?
3) which reaction is favoured?
4) does the equilibrium shift to the right or left?
5) what happens to the concentration of products and reactants?
In the reaction: H2 (g) + I2 (g) -><- 2HI(g), what would happen if more iodine is added?
The forward reaction would be favoured in an attempt to counteract the increase of I concentration. The reaction will shift to the right, increasing the concentration of products and decreasing the concentration of reactants.
If Keq is less than one…
the mixture will contain mostly reactants
If Keq is greater than one…
the mixture will contain mostly products.
What is the difference between the equilibrium constant and reaction quotient?
The reaction quotient is a ratio of products and reactants for any chemical system, whereas Keq is the ratio for a system at equilibrium.
If Q is less than K…
the forward reaction will be favoured until equilibrium
If Q is greater than K…
the reverse reaction will be favoured until equilibrium
If Q is equal to K…
the reactions has reached equilibrium
What is the Keq expression for the production of ammonia?
(NH3)2 / (H2)3(N2)
When will the equilibrium constant be changed?
When the temperature is increased/decreased
