Question

# To understand the relationship between the equilibrium constant and rate constants. For a general chemical equation...

To understand the relationship between the equilibrium constant and rate constants.

For a general chemical equation

A+B⇌C+D

the equilibrium constant can be expressed as a ratio of the concentrations:

Kc=[C][D][A][B]

If this is an elementary chemical reaction, then there is a single forward rate and a single reverse rate for this reaction, which can be written as follows:

forward ratereverse rate==kf[A][B]kr[C][D]

where kf and kr are the forward and reverse rate constants, respectively. When equilibrium is reached, the forward and reverse rates are equal:

kf[A][B]=kr[C][D]

Thus, the rate constants are related to the equilibrium constant in the following manner:

Kc=kfkr=[C][D][A][B]

Part A

For a certain reaction, Kc = 5.79×108 and kf= 634 M−2⋅s−1 . Calculate the value of the reverse rate constant, kr, given that the reverse reaction is of the same molecularity as the forward reaction.

Express your answer with the appropriate units. Include explicit multiplication within units, for example to enter M−2⋅s−1include ⋅ (multiplication dot) between each measurement.

kr =

Part B

For a different reaction, Kc = 7.92×105, kf=6.77×105s−1, and kr= 0.855 s−1 . Adding a catalyst increases the forward rate constant to 2.24×108 s−1 . What is the new value of the reverse reaction constant, kr, after adding catalyst?

Express your answer with the appropriate units. Include explicit multiplication within units, for example to enter M−2⋅s−1include ⋅ (multiplication dot) between each measurement.

kr =

Part C

Yet another reaction has an equilibrium constant Kc=4.32×105 at 25 ∘C. It is an exothermic reaction, giving off quite a bit of heat while the reaction proceeds. If the temperature is raised to 200 ∘C , what will happen to the equilibrium constant?

The equilibrium constant will

Yet another reaction has an equilibrium constant  at 25 . It is an exothermic reaction, giving off quite a bit of heat while the reaction proceeds. If the temperature is raised to 200  , what will happen to the equilibrium constant?

 increase. decrease. not change.

#### Earn Coins

Coins can be redeemed for fabulous gifts.