Chapter 2 Flashcards
(20 cards)
When does chemical equilibrium exist?
When the forward rate of a chemical reaction equals the reverse rate
what kind of properties are constant at equilibrium?
macroscopic
What are some macroscopic properties?
pH, temperature, colour, pressure
What is le chatelier’s principle?
An equilibrium system subjected to a stress will shift to partially alleviate the stress and restore equilibrium
What will happen if a reactant/product is added/removed?
- added: will shift to remove some of the added chemical
- removed: will shift to add some of the removed chemical
How will changing the surface area affect a heterogeneous equilibrium reaction?
no effect- because the fwd/rvs rates occur on the same surface
How will adding a catalyst change the equilibrium?
no effect, but reaches the equilibrium sooner
what is entropy?
the state of disorganization or randomness
order of determining whether entropy is increasing or decreasing?
1) phase (g>aq>l>s)
2) # molecules
3) bonding
what are the two thermodynamic drives that influence an equilibrium’s position?
- decreasing enthalpy
- increasing entropy
How do you recognize an equilibrium?
- the system is closed
- opposite reactions occur at the same rate
- no visible changes
- the temp @ equilibrium is constant
Are the concentration of the reactants and products equal at equilibrium?
no
How do you find minimum enthalpy?
find where it says energy
What happens when you increase/decrease the temp of an equilibrium?
increase temp - endothermic direction
decrease temp- exothermic direction
What happens when you increase/decrease the pressure of an equilibrium?
increase: The reaction will shift to the side with the least #of moles
decrease: The reaction will shift to the side with the most #of moles
What happens when the concentration of gas of the reactants is increased?
reaction will shift to the right to use up the added reactant
What happens when the concentration of gas of the products is increased?
Reaction will shift to the left to get rid of the excess product
How do you affect the equilibrium of a solution?
Change the concentration of just an ion and not a whole substance
what is a spectator ion?
ions that appear on both sides of the equation and cancel out (play no part in the equilibrium)
What will happen when you change the amount of a solid or liquid in an equilibrium?
nothing
