I NEED HELP ASAP! THIS IS URGENT! I JUST NEED HELP WITH QUESTION 6 AND THE SUMMA

Question

I NEED HELP ASAP! THIS IS URGENT! I JUST NEED HELP WITH QUESTION 6 AND THE SUMMARY.

Le Chatelier’s Principle

Objective : Study equilibrium and Le Chatelier’s Principle.

Use the “LAB : HOW TO…” link from the class website if you need help with how to use balance, Bunsen burner… and such.

___________________CUT HERE _______________________

Procedure :

I ) NaCl (s)   ßà   Na+ (aq)   + Cl- (aq)

           (1) *Add few drops of conc. HCl to 2 to 3 mL of saturated NaCl solution.

^^^What is the stress and which direction should the equilibrium shift?   

II ) NH4Cl(s) ßà NH4+ (aq) + Cl-(aq)

           (2) *Add few drops of conc. HCl to 2 to 3 mL of saturated NH4Cl solution.

III ) Fe+3(aq) + SCN-(aq) ßà Fe(SCN)+2(aq)

           (3) Prepare a stock solution by mixing 2mL each of 0.1M FeCl3 and 0.1M KSCN in 100mL graduated cylinder. Add enough water to make 100mL solution. Note the color. If you are the first one to use this station, make this solution and save it for the rest of the class. If you are using someone else’s stock solution, make sure to make observations of each reactant.

(4) *Add about 1mL of 0.1M FeCl3 to about 5mL of stock solution.

(5) *Add about 1mL of 0.1M KSCN to about 5mL of stock solution.

^^^What is the stress and which direction should the equilibrium shift

(6) *Add 0.1M AgNO3 DROPWISE (less than 1mL) to about 5mL of stock solution until almost all the color is discharges. (The white ppt is a mixture of AgCl and AgSCN.) Split the solution into two test tubes including the precipitate.

                   (6a) Add 0.1M KSCN dropwise (about 2mL) to one tube

                   (6b) Add 0.1M FeCl3 dropwise (about 2mL) to the other tube.

IV) 2CrO4 –2(aq)    +   2H+ (aq)   ßà Cr2O7 –2(aq)    +    H2O(l)

           (7) *Add 2 drops of 6M HNO3 to about 3mL of 0.1M K2CrO4.

^^^What is the stress and which direction should the equilibrium shift?  

           (8) Add 10% NaOH to (7) dropwise until the original color of K2CrO4 is restored.

(9) *Add 2 drops of 6M H2SO4 to about 3mL of 0.1M K2CrO4.

(10) Add 10% NaOH to (9) dropwise until the original color of K2CrO4 is restored.

V) Co(H2O)6 +2(aq)   + 4Cl-(aq)   ßà CoCl4 –2(aq) + 6 H2O

           (11) *Add about 3mL of Conc. HCl solution dropwise to about 2mL (no more than) of 0.1M CoCl2.

           (12) Add water to (11) until the reverse reaction is evident.

VI) NH3(g)   + H2O(l) ßà NH4+ (aq)   + OH-(aq)

           (13) Prepare a stock solution by mixing 4 drops of conc. NH4OH and 3 drops of phenolphthalein in 100mL graduated cylinder. Add enough water to make 100mL solution. Note the color. If you are the first one to use this station, make this solution and save it for the rest of the class. If you are using someone else’s stock solution, make sure to make observations of each reactant.

(14) *Dissolve a very small amount of solid NH4Cl in about 5mL of stock solution.

(15) *Add a few drops of 6M HCl to about 5mL stock solution.

___________________CUT HERE _______________________

Prelab Questions :

(PL1) There are many procedures with * in the front. After reading all of the procedures, what do you think * means? It has more to do with the procedures than reactions.

(PL2) Draw a data table you will be filling in during the lab. Include all the measurements that will be made in this lab and qualitative observation if needed.

Postlab Questions :

(Q1) In step (1), which direction DID the equilibrium shift? What was the visual indication of the shift?

(Q2) In step (5), which direction DID the equilibrium shift? What was the visual indication of the shift?

(Q3) In step (7), which direction DID the equilibrium shift? What was the visual indication of the shift?

(Q4) Write a balanced net ionic equation showing what happened in step (6).  

(Q5) In step (6a), what is the stress and which direction DID the equilibrium shift? What was the visual indication of the shift? Use the equation from Q4.

(Q6) In step (10) , which direction DID the equilibrium shift? Using balanced equations, explain the direction of this shift.

Summary

Rewrite 6 chemical equations given in the procedures. Under each component, write its characteristic such as color.    For example,  

        A        +       B            à       C     +            D

(light blue)   (no color)            (red)     (pink in the presence of indicator)

Make sure to include HEAT as a reactant or product if now known.

Explanation / Answer

Q6. In the previous step that means in step 9 due to the presence of acid, the equilibrium is at the right side in step 10 by addition of 10% NaOH which is base acid get neutralize and the equilibrium will shift to the left side that is the reactant side.

Summary:

NaCl (s) ßà Na+ (aq) + Cl- (aq)

(white solid) (no color) (no color)

NH4Cl(s) ßà NH4+ (aq) + Cl-(aq)

(white solid) (no color) (no color)

Fe+3(aq) + SCN-(aq)    ßà Fe(SCN)+2(aq)

(yellowish) (no color) (reddish brown)

2CrO4 –2(aq)    + 2H+ (aq) ßà Cr2O7 –2(aq) +    H2O(l)

(yellow) (no color) (orange) (no color)

Co(H2O)6 +2(aq) + 4Cl-(aq) ßà CoCl4 –2(aq) + 6 H2O

(pink) (no color) (blue)   

NH3(g) + H2O(l) ßà NH4+ (aq) + OH-(aq)

(no color) (no color)

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