equilibrium I and II

What’s homogeneous equilibria

Reactants and products in the same state. So all reactants and products are included in the final Kc expression.

Le Chatelier’s Principle only works for homogeneous equilibria

What’s heterogeneous equilibrium

When a systems state of equilibrium contains components from multiple phases.

Solids and liquids aren’t included in Kc. This is due to their concentrations remaining constant

What’s le chatelier’s principle in regard to catalysts

Catalysts have no effect on the position of equilibrium. A catalyst will speed up the rate of the forward and backward reaction equally.

The rate at which equilibrium is reached speeds up, but has no effect on yield

Conditions for making ethanol along with le chatelier’s principle

60atm, 300°c, phosphoric acid catalyst.

Temp- forward is exothermic so decreasing temp shifts eq right, producing more ethanol. Low temp= slow rate. So it’s a compromise between yield and rate.

Pressure- high pressure shifts eq right, producing more ethanol. High pressure increases rate too. But is expensive. Compromise between yield/speed and cost.

How to calculate Kc

Change in mol (mol at eq - initial mol).

Conc at eq (mol/vol).

Put the conc’s into the Kc expression and solve for Kc. Answer in mol dm -3 of units

What’s partial pressure

The pressure a gas would exert of it occupied the volume alone.

Calculate partial pressure of a mix of gasses by adding all their partial pressures.

partial pressure= mole friction of a gas x total pressure

What’s Kp

Expression of the concentration of reactants and products of reversible reactions in terms of their partial pressures.

Only includes gases, unlike Kc which includes aqueous and gases

How to calculate Kp

Mole fraction (mol at eq / total moles).

X total pressure.

= partial pressure.

Put partial pressure in Kp expression, answer in atm if units

How does temperature effects Kp and Kc

Kp and Kc anre only valid for one temperature.

TinEndo

In an exothermic reaction, increasing temp decreases Kp/ Kc

In an endothermic reaction, increasing temp increases Kp/ Kc

How do pressure, concentration, and catalysts effect Kp and Kc

They have no effect