Chemistry 3.1.6 Chemical Equilibria and Kc

AQA A Level Chemistry Chemical Equilibria and Kc

One line from top and one from bottom curving down, X as soon as both level out

sketch a graph to represent concentration of products and reactants over time for a closed system as it reaches towards equilibrium. Put a cross at equilibrium.

When the rate of the fowards reaction = the rate of the backwards reaction. The concerntration of both prods and reactants is constant at dynamic equilibrium.

define dynamic equilibrium

Closed system with all prods and reactants in same state \n \n Closed = Stop any products escaping and altering the concentration.

What is a required condition for equilibrium reactions? Why?

f a reaction at equilibrium is subject to change in Temperature pressure or concentration the position of equilibrium will shift to oppose it.

State le Chatelier's principle

Temp Up = Favours backwards reaction  \n Temp Down = Favours fowards reaction

\n Preasure Up = Favours fowards reaction \n Preasure Down = Favours backwards reaction

\n Conc Of N2 Up = Favours Foward reaction \n Conc Of N2 Down = Favours Backwards reaction

What is the effect of Temp Pressure and Concentration of N2 On this equilibrium?  N2+3H2 ⇌ 2NH3 DH = -470KjMol-1

H2SO4 catalyst

Hydration reaction \n Conds = 300ºC 60-70ATM. 

\
300º Is high and favours the backwards reaction. Too low of a tempriture would lead to a very slow rate of reaction. \n 60-70ATM Favours the foward reaction thus yeild of ethanol. We don't go higher due to the expensive nature of the equipment needed to maintain high preasure. \n \n This very concept can be applied to all sorts of Equilibrium reactions.

Ethanol is made by reacting Ethene with Water in the presence of a what Catalyst.

This is a what kind of Reaction.

State the conditions and then explain them.  \n C2H4 + H2O ⇌ CH3CH2OH DH = -46KjMol-1 

\[C\]\[D\]2 / \[A\]2\[B\]3 \n \n Units =  \n Moldm-3Moldm-3Moldm-3 / Moldm-3Moldm-3Moldm-3Moldm-3Moldm-3 \n \n =Mol6Dm-2

Write an expression for Kc For the following: 2A +3B ⇌ C + 2D | What are the units?

ONLY TEMP  \n \n PREASURE = NO

The equilibrium is being disturbed by the pressure change and responds to re-establish the value of the equilibrium constant. \n \n CONC = NO

When the concentration of a product is increased, the reaction proceeds in reverse to decrease the concentration of the products. When the concentration of a reactant is increased, the reaction proceeds forward to decrease the concentration of reactants. \n \n CATALYST = NO \n Only gets the system to equilibria quicker

Which environmental condition(s) change Kc? and why/why others do not