E770: Prep Notes | Lecture Demonstration Manual General Chemistry

Skip to main content TranslateEnglishSpanishChineseFrenchGermanKoreanLaoNepaliJapaneseTibetan

Search

Enter the terms you wish to search for.

Other ways to search:

• Events Calendar
• Campus Map

• Home
• General Reactions
• Quantum
• Molecular Structure
• Gases
• Thermochemistry
• Organic
• Equilibrium
• Electrochemistry
• Kinetics
• Demo List by Class

E770: Prep NotesE770: Prep Notes

Introduction

The addition of NH4Cl to a solution of ammonia shows the effect of adding a common ion to a system at equilibrium.

Equations

 NH3 + H2O ↔ NH4+ + OH-

 Addition of NH4Cl adds NH4+, driving the reaction to the left and consuming OH-.

Prior to Lecture  (prep time ~ 5 min.)

1. Prepare the following chemicals:

1.   3M NH3 (ammonia) in a dropper bottle
2.  a few grams of NH4Cl (ammonium chloride)
3.  phenolphthalein indicator in dropper bottle
4.  distilled water in wash bottle
5.  two small beakers (50 or 100mL)
6.  scoopula

To Conduct Demonstration:

1. Add water to each of two beakers.  Add 2 drops of phenolphthalein to each.
2.  Add a few drops of 3M NH3 to each beaker.  The solution will turn pink.
3.  Add a scoop of solid NH4Cl to one of the beakers.  The pink color will become very faint or disappear.  Use the other beaker as a reference.

Safety and Disposal

Goggles should be worn. 

Chemicals may be sink disposed.

• E710: Complex Ion – Shifting Equilibrium
• E715: Effect of Temperature – NO2/N2O4
• E720: Effect of temperature - [Co(H2O)6]^2+/[CoCl4]^2-
• E730: Complex Ions – Solubility and Complex Ion Equilibria
• E735: Complex Ions and Precipitates – Nickel(II) compounds
• E740: Equilibrium – Complex Ions – Metal + Ammonia Complexes
• E750: Acid Base – pH of Common Household Items
• E755 - Acid/Base - Universal Indicator and Dry Ice
• E760: Acid Base – Amphoterism of Aluminum Hydroxide
• E765: Acid Base – pH Rainbow
• E770: Acid/Base – Common Ion Effect
  • E770: Prep Notes
• E775: Acid Base – Titration
• E780: Acid/Base – Salts as Acids and Bases
• E785: Acid/Base – Effectiveness of a Buffer
• E790: Acid/Base – Conductimetric Titration – Ba(OH)2 + H2SO4