Precipitation Rxns

Name: Savannah Dalrymple Date: October 8 and 9, 2009 2 Hours Lab Partners: Kaylynn Antoniazzi and Jordan Wiggins Station Number: 6 Title: Precipitation Reactions Objective: The objective of this lab was to see if a precipitate was created by reacting two ions and by doing so, determine which combinations of ions are insoluble. Introduction: A precipitation reaction is an exchange reaction that produces an insoluble salt, or precipitate, from soluble reactants. Some reactants are soluble and some are insoluble. The soluble compounds are almost all salts of Na+, K+, and NH4+, salts of nitrate, chlorate, prechlorate, and acetate. All salts of Cl-, Br-, and I-, are soluble except for those of Ag+, Hg22+, and Pb2+. Compounds containing F- are soluble except for fluorides containing Mg2+, Ca2+, Sr2+, Ba2+, and Pb2+. Also, salts of sulfate are soluble except sulfates of Ca2+, Sr2+, Ba2+, and Pb2+. Some compounds are insoluble. These include most salts of carbonate, phosphate, oxalate, chromate, and most metal sulfides. The exceptions to the insoluble compounds are salts of NH4+ and all the alkali metal cations. Most metal hydroxides and oxides are insoluble except for Ba(OH)2, which is soluble. These solubility rules are not absolute and there are a few exceptions under certain conditions. The equations for the reactions are as follows: Cu(NO3)2(aq) Cu(NO3)2(aq) Cu(NO3)2(aq) Cu(NO3)2(aq) Cu(NO3)2(aq)

+ + + + +

Na2CO3 (aq) -> CoCO3(s) + 2Na(NO3) (aq) Na2SO4 (aq) -> CuSO4(aq) + 2Na(NO3) (aq) 2NaOH (aq)-> Cu(OH)2(s) + 2Na(NO3) (aq) 2 NaCl(aq) ->CuCl2(aq) + 2Na(NO3) (aq) 2 KI(aq) -> CuI2(aq)+ 2K(NO3) (aq)

Ba(NO3)2(aq) + Na2CO3(aq) -> BaCO3(s) + 2Na(NO3) (aq) Ba(NO3)2(aq) + Na2SO4(aq) -> BaSO4(s) + 2Na(NO3) (aq) Ba(NO3)2(aq) + 2NaOH(aq) -> Ba(OH)2(aq) + 2Na(NO3) (aq) Ba(NO3)2(aq) + 2NaCl(aq) ->BaCl2(aq) + 2Na(NO3) (aq) Ba(NO3)2(aq) + 2KI(aq) -> BaI2(aq) +2K(NO3) (aq) Pb(NO3)2(aq)+ Pb(NO3)2(aq)+ Pb(NO3)2(aq)+ Pb(NO3)2(aq)+ Pb(NO3)2(aq)+

Na2CO3(aq) -> Pb(CO3) (s) + 2Na(NO3) (aq) Na2SO4(aq) -> Pb(SO4) (s) +2Na(NO3) (aq) NaOH (aq)-> Pb(OH)2(s) +2Na(NO3) (aq) NaCl(aq) -> PbCl2(s) +2Na(NO3) (aq) KI(aq) -> PbI2(s) + 2K(NO3) (aq)

Co(NO3)2(aq) + Co(NO3)2(aq) + Co(NO3)2(aq) + Co(NO3)2(aq) + Co(NO3)2(aq) +

Na2CO3(aq) -> Co(CO3) (s) + 2Na(NO3) (aq) Na2SO4 (aq-> Co(SO4) (aq) + 2Na(NO3) (aq) 2NaOH(aq) -> Co(OH)2(s) +2Na(NO3) (aq) NaCl(aq) ->CoCl2(aq) +2Na(NO3) (aq) KI(aq) -> CoI2(aq) + 2K(NO3) (aq)

Ag(NO3)2(aq) + Ag(NO3)2(aq) + Ag(NO3)2(aq) + Ag(NO3)2(aq) + Ag(NO3)2(aq) +

Na2CO3(aq) -> Ag(CO3) (s) + 2Na(NO3) (aq) Na2SO4(aq)-> Ag(SO4) (aq) +2Na(NO3) (aq) 2NaOH(aq)-> Ag(OH)2(s) +2Na(NO3) (aq) 2NaCl(aq) -> AgCl2(aq) +2Na(NO3) (aq) 2KI(aq)-> AgI2(aq) + 2K(NO3) (aq)

Experimental Section: First, the solutions were prepared. The solutions were prepared by measuring the quantity of the solid ions by the use of a scale. The measured solid ions were then placed into a 250 mL volumetric flask. About 167mL of ionized water was then added to the volumetric flask. The cap was placed on the top of the volumetric flask and solid ions

and the water were then swirled, dissolving the solid ion and creating a homogenous mixture. The remaining 83mL was added up to the 250mL line and then mixed again. The 250mL of the ions and water was placed into small containers using a graduated cylinder 0.100 m Cu(NO3)2 1L

25mL

1L

= 0.00250 moles of Cu(NO3)2

1000mL

and a pipette. The amounts of solid ions added to the flask were determined as follows:

0.00250 m Cu(NO3)2

187.57 g Cu(NO3)2 1 m Cu(NO3)2

= 0.469 grams of Cu(NO3)2

The solution of NaOH had to be diluted from a 0.200 M sample to a 0.100 M. The 0.200 M sample was 250mL. The amount of ionized water to be added was calculated as follows: V1C1 = V2C2 .1X = .2(250) .1X = 50 X = 500 500- 250 = 250mL To perform dilution, 250mL of ionized water was added to the original 250mL of 0.200 M solution and mixed. Next, the reactions were performed. 10 drops of the cation solutions (copper (II) nitrate, barium nitrate, lead (II) nitrate, cobalt (II) nitrate, and silver nitrate) were added to test tubes. Then, 10 drops of the anionic solutions (sodium carbonate, sodium sulfate, sodium hydroxide, sodium chloride, and potassium iodide) were added to the test tube of each cationic solution. If the solution of the reactants were insoluble, a precipitate was formed. Results: Solubility Predictions Cu2+ 2CO3 Precipitate SO42+ NR OHPrecipitate ClNR INR

Ba2+ Precipitate Precipitate NR NR NR

Pb2+ Precipitate Precipitate Precipitate Precipitate Precipitate

Co2+ Precipitate NR Precipitate NR NR

Ag2+ Precipitate NR Precipitate Precipitate Precipitate

Na2CO3 NR White (P) White (P) Baby pink (P)

Na2SO4 NR White (P) White (P) NR

NaCl NR NR NR NR

KI Orange (P) NR Yellow(P) NR

Light Yellow (P)

NR

NaOH Light blue (P) White (P) White (P) Cobalt blue (P) Light brown (P)

Reactions Cu(NO3)2 Ba(NO3)2 Pb(NO3)2 Co(NO3)2 Ag(NO3)2

Discussion and Calculations:

Cloud white (P)

Light green (P) (P) – Precipitate

During this lab, precipitates were formed from reactions of cation and anion solutions. Some of the reactions were soluble and did not produce a precipitate while others, such as the reaction of barium nitrate and sodium carbonate, created a precipitate. Most cations that reacted with Na2CO3 produced a precipitate. All but one cation (Ag(NO 3)2) that reacted with NaCl were soluble and did not create a precipitate. A few of the precipitates were not expected. For example, the mixture of Cu(NO3)2 and KI resulted in a precipitate that was not planned. There are a few possibilities of error. Human error from the mixing of the solutions as well as possible contamination of solutions from multiple uses could have been present. Mechanical error was possible. For example, the scales that measured the dry ingredients only measured to the hundredths place and the graduated cylinder measured to only the tenths place. Calculations - Cations: Copper Nitrate - Cu(NO3)2 0.100 m 250mL 1L 187.57 g Cu(NO3)2 Cu(NO3)2 = 4.69 grams 1L 1000mL 1 m Cu(NO3)2 of Cu(NO3)2 Barium Nitrate - Ba(NO3)2 0.0250 m of Ba(NO3)2

261.34 g Ba(NO3)2 1 m Ba(NO3)2

0.0250 m of Pb(NO3)2

331.21 g Pb(NO3)2 1 m Pb(NO3)2

0.0250 m Co(NO3)2

182.94 Co(NO3)2 1 m Co(NO3)2

0.0250 m Ag(NO3)2

169.87 g Ag(NO3)2 1 m Ag(NO3)2

= 6.53 grams of Ba(NO3)2 Lead (II) Nitrate - Pb(NO3)2 = 8.28 grams of Pb(NO3)2 Cobalt (II) Nitrate - Co(NO3)2 = 4.57 grams of Co(NO3)2 Silver Nitrate - Ag(NO3)2

Calculations - Anions:

= 4.25 grams of Ag(NO3)2 Sodium Carbonate – Na2CO3

0.0250 m Na2CO3

105.99 g Na2CO3 1 m Na2CO3

0.0250 m Na2SO4

142.04 g Na2SO4 1 m Na2SO4

0.0250 m NaOH

39.10 g NaOH 1 m NaOH

0.0250 m NaCl

58.44 g NaCl 1 m NaCl

= 2.65 grams of Na2CO3 Sodium Sulfate - Na2SO4 = 3.55 grams of Na2SO4 Sodium Hydroxide – NaOH = 0.980 grams of NaOH Sodium Chloride - NaCl

Potassium Iodide - KI

= 1.46 grams of NaCl

0.0250 m KI

166.00 g KI 1 m KI

= 4.15 g of KI

Equations: Cu(NO3)2 and NaOH 1. Cu(NO3)2(aq) + 2NaOH (aq)-> Cu(OH)2(s) + 2Na(NO3) (aq) 2. Cu2+(aq) + 2(NO3)- (aq) + 2Na+(aq) + 2OH-(aq) -> Cu(OH)2 (s) + 2Na+(aq) +2(NO3)- (aq) 3. Cu2+ (aq) + 2OH- (aq) -> Cu(OH)2 (aq) Cu(NO3)2 and KI 1. Cu(NO3)2(aq) + 2 KI(aq) -> CuI2(aq)+ 2K(NO3) (aq) 2. Cu2+ (aq) + 2(NO3)-(aq) + 2 K+ (aq) + 2I-(aq) -> CuI2(s)+ 2K+ + 2(NO3)- (aq) 3. Cu2+ (aq) + 2I-(aq) -> CuI2(s) Ba(NO3)2 and Na2CO3 1. Ba(NO3)2(aq) + Na2CO3(aq) -> BaCO3(s) + 2Na(NO3) (aq) 2. Ba2+ (aq) + 2(NO3)-(aq) + 2Na+ (aq) + (CO3)2-(aq) -> BaCO3(s) + 2Na+ (aq) + 2(NO3)- (aq) 3. Ba2+ (aq) + (CO3)2-(aq) -> BaCO3(s) Ba(NO3)2 and NaOH 1. Ba(NO3)2(aq) + 2NaOH(aq) -> Ba(OH)2(aq) + 2Na(NO3) (aq) 2. Ba2+(aq) + 2(NO3)(aq) + 2Na2+(aq) + 2OH-(aq) -> Ba2+(aq) + 2(OH)(aq) + 2Na(NO3)(s) 3. Na2+(aq) + (NO3)(aq) - > Na(NO3)(s) Pb(NO3)2 and Na2CO3 1. Pb(NO3)2(aq)+ Na2CO3(aq) -> Pb(CO3) (s) + 2Na(NO3) (aq) 2. Pb2+ (aq) + 2(NO3)-(aq)+ 2Na+ (aq) +(CO3)2-(aq) -> Pb(CO3) (s) + 2Na+ (aq) + 2(NO3)- (aq) 3. Pb2+ (aq) +(CO3)2-(aq) -> Pb(CO3) (s) Pb(NO3)2 and Na2SO4 1. Pb(NO3)2(aq)+ Na2SO4(aq) -> Pb(SO4) (s) +2Na(NO3) (aq) 2. Pb2+ (aq) + 2(NO3)-(aq)+ 2Na+(aq) + SO42-(aq) -> Pb(SO4) (s) +2Na +(aq) + 2(NO3)- (aq) 3. Pb2+ (aq) + SO42-(aq) -> Pb(SO4) (s) Pb(NO3)2 and NaOH 1. Pb(NO3)2(aq)+ NaOH (aq)-> Pb(OH)2(s) +2Na(NO3) (aq) 2. Pb2+(aq)+ 2(NO3)-(aq) + Na- (aq) + OH- (aq) -> Pb(OH)2(s) +2Na+ (aq) + 2(NO3)- (aq) 3. Pb2+(aq) + OH- (aq) -> Pb(OH)2(s) Pb(NO3)2 and KI 1. Pb(NO3)2(aq)+ KI(aq) -> PbI2(s) + 2K(NO3) (aq) 2. Pb2+(aq) + 2(NO3)-(aq) + 2K+ (aq) + 2I-(aq) -> PbI2(s) + 2K+ + 2(NO3)- (aq) 3. Pb2+(aq) + 2I-(aq) -> PbI2(s) Co(NO3)2 and Na2CO3 1. Co(NO3)2(aq) + Na2CO3(aq) -> Co(CO3) (s) + 2Na(NO3) (aq) 2. Co2+(aq) + 2(NO3)-(aq) + 2Na+(aq) + 2(CO3)-(aq) -> Co(CO3) (s) + 2Na+(aq) +2 (NO3)-(aq) 3. Co2+(aq) + 2(CO3)-(aq) -> Co(CO3) (s) Co(NO3)2 and NaOH 1. Co(NO3)2(aq) + 2NaOH(aq) -> Co(OH)2(s) +2Na(NO3) (aq) 2. Co2+(aq)+ 2(NO3)-(aq) + 2Na2+(aq) + 2(OH)-(aq) -> Co(OH)2(s) +2Na2+ (aq) + 2(NO3)- (aq) 3. Co2+(aq) + 2(OH)-(aq) -> Co(OH)2(s) Ag(NO3)2 and Na2CO3 1. Ag(NO3)2(aq) + Na2CO3(aq) -> Ag(CO3) (s) + 2Na(NO3) (aq) 2. Ag2+ (aq) +2(NO3)-(aq) + 2Na2+(aq) +(CO3)2-(aq) -> Ag(CO3) (s) + 2Na2+ (aq) + 2(NO3-) (aq) 3. Ag2+ (aq) +(CO3)2-(aq) -> Ag(CO3) (s) Ag(NO3)2 and NaOH 1. Ag(NO3)2(aq) + 2NaOH(aq)-> Ag(OH)2(s) +2Na(NO3) (aq)

2. Ag2+(aq) + 2(NO3)-(aq) + 2Na+(aq) + 2(OH)-(aq)-> Ag(OH)2(s) +2Na+ (aq) + 2(NO3)- (aq) 3. Ag2+(aq) + 2(OH)-(aq)-> Ag(OH)2(s) Ag(NO3)2 and NaCl 1. Ag(NO3)2(aq) + 2NaCl(aq) -> AgCl2(aq) +2Na(NO3) (aq) 2. Ag2+(aq) + 2(NO3)-(aq) + 2Na+(aq) +2Cl-(aq) -> AgCl2(s) +2Na+(aq) + 2(NO3)-(aq) 3. Ag2+(aq) +2Cl-(aq) -> AgCl2(s) Ag(NO3)2 and KI 1. Ag(NO3)2(aq) + 2KI(aq)-> AgI2(s) + 2K(NO3) (aq) 2. Ag2+(aq) + 2(NO3)-(aq) + 2K+(aq) +2I-(aq) -> AgI2(s) + 2K(NO3)(aq) 3. Ag2+(aq) +2I-(aq) -> AgI2(s)