Double Displacement Lab Report 2/16/17 Period 8 by Parth Datar, Daniel Djelmis, and David Armah

Background

Double Displacement:

Double displacement reactions are reactions in which the cations and anions of two compounds change partners and form two completely new products. For a double displacement reaction to occur one of the products must be insoluble.

Double Displacement Equation

Insoluble Salt:

Insoluble salts are ionic metal compounds that do not dissolve in water. If insoluble salts are produced as a result of a double displacement reaction between two soluble, or aqueous, substances, the insoluble salts are called precipitates.

Silver chloride:

Silver chloride is a white crystalline solid, that is photosensitive, meaning it undergoes a chemical reaction when acted upon by light. In this particular case, when under light, silver chloride decomposes into silver metal and elemental chlorine. Due to this photosensitive property, silver chloride is often used to coat photographic lenses. When placed under light, the silver chloride darkens, developing the film. Silver chloride also has properties of a disinfectant, and is often used in wound healing products ("Silver Chloride Formula").

Source: Patterson, Val

Copper hydroxide

Copper hydroxide is a light blue powder like crystal ("Copper Hydroxide"). Its use is primarily as a fungicide, or a chemical that destroys fungus. It can be used on a wide variety of fruits and vegetables, but is hazardous to fish ("copper hydroxide").

Source: "Crop Protection International"

Purpose

The purpose of the lab was to observe double displacement reactions and understand the conditions in which said reactions occur.

Materials

  • 2 pipets
  • 1 well plate
  • 1 toothpick
  • 1 q-tip
  • 100 mg of AgNO3
  • 100 mg of FeCl3
  • 100 mg of NaOH
  • 100 mg of CuSO4
Pipets

Prediction Reaction #1

Molecular: FeCl3(aq) + 3AgNO3(aq) --> Fe(NO3)3(aq) + 3AgCl(s)

Complete Ionic: 1Fe(3+)(aq) + 3Cl(1-)(aq) + 3Ag(1+)(aq) + 3NO3(1-)(aq) --> 1Fe(3+)(aq) + 3NO3(1-)(aq) + 3AgCl(s)

Net Ionic: Ag(1+)(aq) + Cl(1-)(aq) --> AgCl(s)

Prediction Reaction #2

Molecular: 2NaOH(aq) + CuSO4(aq) --> Na2SO4(aq) + Cu(OH)2(s)

Complete Ionic: 2Na(1+)(aq) + 2OH(1-)(aq) + Cu(2+)(aq) + SO4(2-)(aq) --> 2Na(1+)(aq) + SO4(2-)(aq) + Cu(OH)2(s)

Net Ionic: Cu(2+)(aq) + 2OH(1-)(aq) --> Cu(OH)2(s)

Procedure

  • Holding the pipette vertically, 2 drops of each solution were placed in the designated boxes of the well plate.
  • Each mixture was stirred carefully using a clean toothpick.
  • Whether a reaction had occurred or not was reacted and results were photographed.
  • After the completion of all reactions, the contents were dumped down the sink with plenty of water. The wells were cleaned using a q-tip.
  • The lab area was ensured to be clean and dry. Hands were washed. Clean-up stamps were obtained by instructor.

Data

Well A2: silver chloride, Well C1: copper hydroxide

Observations

In the well A2, where the reaction between silver nitrate and iron chloride took place, small white-silver clumps formed in the mixture.

In the well C1, where the reaction between copper sulfate and sodium hydroxide took place, tiny blue crystals formed, spread throughout the mixture.

Data Analysis Reaction #1

Net Ionic: Ag(1+)(aq) + Cl(1-)(aq) --> AgCl(s)

The product, silver chloride, matches the description provided by the background research. Silver chloride is supposed to be a white crystalline solid, as it appears to be in the lab. The charges in the net ionic equation are balanced out, and chlorides are by rules of solubility, in the case of silver cations, insoluble, meaning that the reaction can occur. Thus the results are validated.

Data Analysis Reaction #2

Net Ionic: Cu(2+)(aq) + 2OH(1-)(aq) --> Cu(OH)2(s)

The product, copper hydroxide, matches the description provided by the background research. Copper hydroxide is supposed to be a light blue powder like crystal, as it appears to be in the lab. The charges in the net ionic equation are balanced out, and hydroxides are by rules of solubility insoluble, meaning that the reaction can occur. Thus the results are validated.

Conclusion

The purpose was met as the theoretical understanding of double displacement reactions was applied to actual solutions in order to create precipitates.

Silver chloride is a white crystalline solid, much like in the lab, where the product produced was a clump of white-silver precipitate, insoluble in water. This occurs as the silver displaces the iron, bonding with chlorine, and the iron bonds with nitrate. All nitrates are soluble, however, in the case of silver cations, chlorides are insoluble, which results in the precipitate silver chloride. This provides one example of double displacement.

Copper hydroxide is a light blue powder like crystal, much like in the lab, where the product produced was scattered light blue crystals spread throughout the solution insoluble in water. This occurs as copper replaces sodium, bonding with hydroxide, as sodium bonds with sulfate. All sulfates are soluble, however, all hydroxides are insoluble, which results in the precipitate copper hydroxide. This provides another example of double displacement.

Works Cited

"Copper Hydroxide." ChemYQ.com. Chem YQ, n.d. Web. 27 Feb. 2017.

"copper hydroxide." Pmep.cce.cornell.edu. Cornell, n.d. Web. 27 Feb. 2017.

"Crop Protection International." Spiess-Urania.com. Spiess Urania, n.d. Web. 27 Feb. 2017.

Patterson, Val. "Silver Chloride." SaltLakeMetals. Salt Lake Metals, n.d. Web. 27 Feb. 2017.

"Silver Chloride Formula." SoftSchools. SoftSchools, n.d. Web. 27 Feb. 2017.

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