Question

 Data And Report Submission - Le Chatelier's Principle

Part I: Iron Thiocyanate Reaction

 1. For test tubes 2 through 6, explain how each change affected the equilibrium in terms how each change affected the value of Qc or Kc and how this is consistent with your observation.

 2. Based on your results from test tubes 5 and 6, is this reaction exothermic or endothermic. Give a reason for your choice.

 Part II: Cobalt Chloride Reaction

 3. For test tubes 2 through 6, explain how each change affected the equilibrium in terms how each change affected the value of Qc or Kc. and how this is consistent with your observation.

 4. Based on your results from test tubes 5 and 6, is this reaction exothermic or endothermic. Give a reason for your choice.

Answer 1

Fe⁺³_(aq) + SCN^-_(aq) $\rightleftharpoons$ Fe (SCN)⁺²_(aq)

2) addition of KSCN increases the concentration of reactant Q_c decreases hence forward reaction is favored so sloution gets blood red colur

3) addition Fe(NO₃)_3(aq) incerase the concentration of ferric ion hence Q_c decreases hence forward reaction is favored so sloution gets blood red colur

4) additon of NaF doesnt effect the equilibrium hence no change in colour is noticed , solid dont effect equilibrium

5) in Hot water bath it turns almost colourless indicate backward reaction is favored and is endothermic hence forward reaction is exothermic

part II

2) additon of HCl increases the concentraion of Cl^- ion hence Q_c increases if favor backward reaction henc solution get deep blue color

3) additon fo deionised water increases the concentration of the recatant , decreses the Q_c that favor foraward reaction and pink color appears

4) additon of AgNO_3(aq) removes the chloride from the solution hence it decreases the Q_c that favor forward reaction and solution appear pink

5) on hot water bath it become blue means backward reaction is endothermic

6) on cooling if become pink means forward reaction is exothermic

in both reactions the value of K_c remain constant it change only with the change in temperature