PRESSURE.

CHANGE IN PRESSURE:

• For a system that has reactants or products in the gaseous phase, a change in pressure will shift the equilibrium but only if there is a different number of gas molecules on each side of the reaction equation.
• * note* look for little (g) by reactants/products in equation.

Good things to know!

• More gas molecules will exert a greater pressure within a fixed volume. Meaning fewer gas molecules will exert a lower pressure within a fixed volume.
• Pressure is changed by changing the amount or volume of gas present.
• 
• Caption: This diagram shows that the circle with the most molecules, has the most molecules touching the sides, and therefore more pressure is being put on the sides....meaning more pressure is being exerted....

What will happen if the pressure changes...?

• DECREASING PRESSURE:
• Equilibrium shifts in the direction that has more gas molecules in order to increase the pressure.
• INCREASING PRESSURE:
• - Equilibrium shifts in the direction that has fewer gas molecules in order to decrease the pressure.

Examples:

• 
• 
• Caption: IF YOU DECREASE THE PRESSURE,. MOVES TO THE LEFT AS IT HAS MORE MOLECULES.
• Caption: IF YOU INCREASE THE PRESSURE MOVES TO THE RIGHT AS IT HAS FEWER MOLECULES