U7L3E3 & E4: Changes in Pressure & Temperature

Le Chaltelier's Principle states that if a chemical system at equilibrium is stressed,

• the system will adjust to increase the stress
• the system will adjust to reduce the stress
• the system will not adjust

A +  B <--> C + D   ΔH= 151kJ
Rewrite the above equation with energy as a reactant or product:

• A +  B <--> C + D + energy
• A +  B + energy <--> C + D 

For the reaction...
heat  +  N_2(g)  +  O_2(g)  <−>  2NO_(g)
If the heat is removed to the chemical system, the equilibrium will _______.

• shift to the left
• shift to the right
• not shift

For the reaction...
N_{2 (g)} +  3 H_2 (g) <−> 2 NH_{3 (g)}

If the pressure in the system is increased, the reaction will __________________.

•  shift to the left
• shift to the right
• not shift

When  ΔH  is negative it represents a(n)

• exothermic reaction 
• endothermic reaction 

  A_(g) + B_(aq) <> C_(s) 
 ΔH_rxn= -453 kJ/mol
If the [B] is decreased then the reaction is will shift to the _______. 

• Left
• Right
• Stays the same 
• Up

Which stress does not result in a new equilibrium constant?

• changing a concentration

• changing pressure

• increasing temperature

• reducing temperature

Increasing the pressure on an equilibrium system will

• shift the reaction to the side with more moles of chemicals

• shift the reaction to the side with more moles of gas

• shift the reaction to the side with fewer moles of gas

• shift the reaction to the side with fewer moles of chemicals

If an equilibrium constant, K, is 1.8 x 10^-5, at equilibrium

• I will have more reactants

• I will have more products

• I will have roughly equal amounts of reactants and products

• it is impossible to tell how much reactants and products I will have

If a reversible reaction is exothermic in the forward direction, it will be ...

• exothermic in the reverse direction

• endothermic in the forward direction too

• endothermic in the reverse direction

• not involve energy in reverse direction