Equilibrium and Le Chatelier's Principle

In the demonstration, I mixed iron (iii) nitrate with sodium thiocyanate. If I used a small enough concentration of sodium thiocyante, then only one thiocyanate (SCN^-) ion bonds to the iron ion, forming a complex ion called "iron thiocyanato"
(Note that nitrate and sodium are spectator ions and don't participate in the reaction. This is why they are not shown)

What is the correct chemical formula for this reaction?

• Fe³⁺ + SCN → FeSCN

• Fe³⁺ + SCN^- → Fe(SCN)₃

• Fe³⁺ + SCN → FeSCN²⁺

• Fe³⁺ + SCN → Fe³⁺(SCN)₂^-

What color was the FeSCN²⁺ complex in solution?

• Colorless

• Pale yellow

• Deep red

• Blue

What observable change occurs when the reaction mixture is cooled?

• The solution turns yellow

• The red cooler deepens

• Precipitate forms

• Color disappears completely

Since the reaction mixture turned a deeper red when the mixture was cooled, what does this suggest about the reaction?

• It is endothermic

• It is exothermic

• It's getting more embarrassed

• All of the above (somehow)

The reaction is exothermic. What happens to the equilibrium when the mixture is heated?

• It blows up

• It shifts to the right, and makes more FeSCN²⁺

• It shifts to the left, favoring more reactants

• Nothing special happens

According to Le Châtelier’s Principle, which of the following changes will cause the red color to intensify?

• Adding more Fe³⁺ ions

• Removing SCN^- ions

• Heating the solution

• Diluting the solution with water

If you add extra SCN^- to the equilibrium mixture, what will happen?

• The solution will turn colorless

• More Fe³⁺ will form

• The equilibrium will shift to the right

• The reaction will stop

Which of the following best describes Le Châtelier’s Principle?

• At equilibrium, reactants and products are present in equal amounts

• When a system at equilibrium is disturbed, it shifts to counteract the disturbance

• Equilibrium can only be disturbed by adding heat

• The system always favors the products

Which of the following is a characteristic of a reversible reaction?

• The reaction can proceed in both forward and reverse directions

• It stops once reactants are completely consumed

• It only forms reactants and does not produce products

• It goes to completion and produces only products

If a reversible reaction is occurring in a closed container and no further changes in concentration are observed, what can you conclude?

• The reaction has stopped, and no further products are formed

• The reaction is irreversible, and the products are trapped

• The reaction has reached equilibrium, where the forward and reverse rates are the same

• The reaction will continue to shift towards the products indefinitely