Presentation on theme: "Concentration and Temperature. If a stress is applied to a system at equilibrium, the system shifts in the direction that relieves the stress. Stresses."— Presentation transcript:
Concentration and Temperature
If a stress is applied to a system at equilibrium, the system shifts in the direction that relieves the stress. Stresses include: ◦ Change in concentration ◦ Change in volume/pressure ◦ Change in temperature
PCl 5 (g) ⇆ PCl 3 (g) + Cl 2 (g) ΔH=-47kJ
Volume and pressure are related. As the volume goes up the pressure goes down and vice versa. (Boyles Law; P 1 V 1 =P 2 V 2 ) Only gases are affected by a change in volume/pressure You need to count the number of moles on each side of the reaction
2H 2 O (g) ⇆ 2 H 2 (g) + O 2 (g) The left side has 2 molecules of gas, while the right side has 3 molecules of gas If the stress is pressure increasing, shift toward the side with the least number of moles of gas. If the stress is pressure decreasing, shift toward the side with the most number of moles of gas.
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