anachem semi-finals

Chemical equilibrium

Refers to the state of a system in which the concentration of the reactant and the concentration of the products do not change with time

Reactions are reversible

This is indicated by double arrows

Equilibrium

Is the state where the rate of the forward reaction is equal to the rate of the reverse reaction

Gudberg and Waage in 1864

Proposed the general description of the equilibrium, and also known as the law of mass action

Temperature dependent

Equilibrium is ….., how ever it does not change with concentration or pressure

Equilibrium constant expression

What general reaction is this: aA+bB≈cC+dD

Concentration

What does the “{}” mean in the formula

K>1

Favors the products

K<1

Favors the reactants

Pure solid/liquid

Do not appear in expression

Heterogeneous

Weak acid and weak base are what?

Kc

Concentration for aqueous

“K”

Are values that are often written without units

R

Writes the balanced reaction for the predominant reacting species

I

Fills in the initial concentration (must be in molar)

C

Determine the change that is taking in place in terms of x

E

Express the equilibrium concentration in terms of x

Le Chateleir's principle

If a stress is applied to a system at equilibrium, the position of the equilibrium will shift in the direction which reduces stress

consume the added substances

If the concentration increases, the system reacts to

Produce a product

If the concentration decreases, the system reacts to

Shift to the fewest no. Of moles of gas

Increasing pressure results to

Endothermic

Heat is added to the system; heat is reactant

Exothermic

Heat is lost; heat is product