equilibria (physical) Flashcards
Define the dynamic equilibrium
The rate of forward reaction is equal to the rate of the reverse reaction
Give an essential condition for an equilibrium mixture
Occurs in a closed container so products and reactants can’t escape
What is Le chatliers principle
If an equilibrium is disturbed, the equilibrium will move in the direction that reduces the disturbance (increase temp, equilibrium will move to decrease temp)
CH⁴ + H²O <> CO + 3H
^H=+210kJMol‐¹
What effect would increasing the temperaturehave on the position of the equilibrium
The equilibrium position shifts to the right because the forward reaction is endothermic, yield of hydrogen increases
CH⁴ + H²O <> CO + 3H
^H = +210kJMol‐¹
What effect would increasing the pressure have on the equilibrium?
The equilibrium shifts to the left because the products makes more moles of gas than the reverse reaction (4 moles of product, 2 moles of reactant) so yield of hydrogen decreases
CH⁴ + H²O <> CO + 3H
^H = +210kJMol‐¹
Suggest why an industrial chemist may use a high pressure for this production of hydrogen from the the above reaction
The high pressure increases the collision frequency which increases the rate of reaction.
What effect does the catalyst have on the position of the equilibrium
has no effect
What condition affects the value of Kc
Concentration, Catalyst, Pressure, Temperature
Temperature
For the reaction below, deduce an expression for Kc
2[A] + 3[B] + [C] <> [D] + 4[E]
Kc = [D][E]⁴
[A]²[B]³[C]
Deduce the units for Kc
mol‐¹dm‐³
What type of systems is Kc relevant for
Homogenous systems in equilibrium
What does Kc being greater/ lesser than 1 suggest for the position of the equilibrium
Greater than 1 = to the right
Less than 1 = to the left
What effect does decreasing the temperature in an endothermic reaction have on Kc
Kc decreases
What effect does increasing the temperature in an endothermic reaction effect the Kc
Kc increases
What effect does decreasing the temperature in an exothermic reaction have on Kc
Kc increases
