Mass Produced Chemicals and Chemical Equilibrium

These flashcards cover the economic considerations of mass-producing chemicals, the characteristics of reversible reactions and dynamic equilibrium, and the factors affecting the equilibrium constant (Kc).

Raw materials

Resources that chemical companies try to source cheaply and widely to ensure a good sustainable supply.

Overheads

Fixed costs that exist regardless of product volume, such as staff costs, insurance, taxation, and land costs.

Waste costs

Expenses originating from by-product disposal and government regulation on the disposal of chemicals.

Co-products

Secondary products formed during a reaction that can be sold on, though typically at a lower price than the main product.

High atom economies

Reaction pathways that use less raw materials and generate fewer waste products.

Reversible reactions

Chemical reactions that can proceed in both forward and backward directions, represented by the symbol $\rightleftharpoons$.

Dynamic equilibrium

The point in a reversible reaction in a closed system where the rate of the forward reaction equals the rate of the backward reaction.

Closed systems

The necessary environment for a dynamic equilibrium to occur, where no reactants or products can escape.

Forward Reaction (Initial Behavior)

A phase where reactants are used up quickly, which then slows as their concentration drops.

Backward Reaction (Initial Behavior)

A phase where reactants are reformed slowly, which then speeds up as the concentration of products increases.

Equilibrium Constant ($K_c$)

A value that characterizes the status of a reversible reaction, which is only valid for one specific temperature.

Effect of Shifting Right on $K_c$

When a temperature change causes the equilibrium to shift toward the products, the value of $K_c$ will increase.

Effect of Shifting Left on $K_c$

When a temperature change causes the equilibrium to shift toward the reactants, the value of $K_c$ will decrease.

Exothermic Reaction Example

The reaction $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$ which has a enthalpy change of $\text{AH} = -197,kJ,mol^{-1}$.

Increasing Temperature (Exothermic Forward)

Causes the equilibrium to shift in the endothermic direction to oppose the change, resulting in a decrease in $K_c$.

Decreasing Temperature (Exothermic Forward)

Causes the equilibrium to shift in the exothermic direction, resulting in an increase in $K_c$.

Equilibrium Expression for $SO_3$ production

$K_c = \frac{[SO_3]^2}{[O_2][SO_2]^2}$, where increasing product concentration raises $K_c$ and increasing reactant concentration drops it.