5. Reactions in Solution Precipitation

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Partner: Jeff Somvorachith

10/31/24

Lab 5. Reactions in Solution Precipitation

Purpose:

To practice identifying reactions that result in precipitation and practice recognizing and writing equations for double replacement reactions by testing pairs of reagents and looking for signs of chemical change and writing molecular and ionic equations for the reactions.

Prelab: 

1. 1. a. Zinc Sulfide: ZnS
      b. Chromium(III) Hydroxide: Cr(OH)₃
      c. Lead(II) Phosphate: Pb₃(PO₄)₂
      
   2. a. Sodium Chloride: NaCl->Na⁺+Cl^-
      b. Copper(II) Chloride: CuCl₂->Cu²⁺+2Cl^-
      c. Iron(III) Sulfate: Fe₂(SO₄)₃->2Fe³⁺+3SO₄^2-
   3.  Fe(NO₃)₃+K₂CO₃->Fe₂(CO₃)₃ (s)+KNO₃
   4. 0.2M*1L=M₁*2L     M₁=0.1M

Procedure:

1. Use 4-5 drops of each reagent for each pair of your tests. Note and record any sign of reaction. Test all possible pair of combinations of one group A reagent with one group B reagent. Record your observations in the data table in your notebook. Recall that not all pairs will react, and that sometimes the evidence of reaction, especially formation of a precipitate, take a few moments to appear.
2. If there are any combinations about which you doubt, repeat the tests.
3. Return pipettes containing unused portions of the reagent

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solutions to the proper location. Some of the solutions contain transition metal ions, so should not be washed down the drain. Instead, dump the contents onto a paper towel in the tray labeled "transition metal waste". Wash some items with water and clean others with cotton swabs. 

Safety: Barium is toxic, don't touch. wash hands thoroughly.

Data Table:

	CoCl2	CuCl2	AlCl3	BaCl2	NiCl2
NaI	No Reaction	Turned Brown, Precipitated	No Reaction	No Reaction	No Reaction
Na2CO3	Precipitated	Precipitated	Precipitated	Precipitated	Precipitated
Na3PO4	Tuned Purple, Precipitated	Precipitated	Precipitated	Precipitated	Precipitated
Na2SO4	No Reaction	No Reaction	No Reaction	Precipitated	No Reaction
NaOH	Turned Purple, Precipitated	Precipitated	Precipitated	Precipitated	Precipitated

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Conclusion:

a. Formula of Precipitates

	CoCl2	CuCl2	AlCl3	BaCl2	NiCl2
NaI		CuI2
Na2CO3	CoCO3	CuCO3	Al2(CO3)3	BaCO3	NiCO3
Na3PO4	Co3(PO4)2	Cu3(PO4)2	AlPO4	Ba3(PO4)2	Ni3(PO4)2
Na2SO4				BaSO4
NaOH	Co(OH)2	Cu(OH)2	Al(OH)3	Ba(OH)2	Ni(OH)2

b. Molecular Formulas

CuCl₂​(aq)+2NaI(aq)->2CuI₂(s)+2NaCl(aq)

CoCl_2​(aq)+Na₂​CO₃​(aq)->CoCO₃​(s)+2NaCl(aq)

CuCl₂​(aq)+Na₂​CO₃​(aq)->CuCO₃​(s)+2NaCl(aq)

2AlCl₃​(aq)+3Na_2​CO₃​(aq)->Al₂​(CO₃​)₃​(s)+6NaCl(aq)

BaCl_2​(aq)+Na₂​CO₃​(aq)->BaCO₃​(s)+2NaCl(aq)

NiCl₂​(aq)+Na₂​CO₃​(aq)->NiCO_3​(s)+2NaCl(aq)

3CoCl₂​(aq)+2Na_3​PO₄​(aq)->Co_3​(PO₄​)₂​(s)+6NaCl(aq)

3CuCl₂​(aq)+2Na_3​PO₄​(aq)->Cu_3​(PO₄​)₂​(s)+6NaCl(aq)

AlCl₃​(aq)+Na₃​PO₄​(aq)->AlPO₄​(s)+3NaCl(aq)

3BaCl₂​(aq)+2Na₃​PO_4​(aq)->Ba_3​(PO₄​)₂​(s)+6NaCl(aq)

3NiCl₂​(aq)+2Na₃​PO₄​(aq)->Ni₃​(PO_4​)₂​(s)+6NaCl(aq)

BaCl₂​(aq)+Na₂​SO₄​(aq)->BaSO₄​(s)+2NaCl(aq)

CoCl_2​(aq)+2NaOH(aq)->Co(OH)₂​(s)+2NaCl(aq)

CuCl₂​(aq)+2NaOH(aq)->Cu(OH)_2​(s)+2NaCl(aq)

AlCl₃​(aq)+3NaOH(aq)->Al(OH)₃​(s)+3NaCl(aq)

BaCl₂​(aq)+2NaOH(aq)->Ba(OH)₂​(s)+2NaCl(aq)

NiCl₂(aq)+2NaOH(aq)->Ni(OH)₂(s)+2NaCl(aq)

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11/1/24

c. Net ionic formulas

Cu²⁺+2I⁺->CuI₂ 

Co²⁺+Co₃^2-->CoCO₃

Cu²⁺+Co₃²⁺->CoCO₃

2Al³⁺+3CO₃^2-->Al₂(CO₃)₃

Ba²⁺+CO₃^2-->BaCO₃

Ni²⁺+CO₃^2-->NiCO₃

3Co²⁺+2PO₄^3-->Co₃(PO₄)₂

3Cu²⁺+2PO₄^3-->Cu₃(PO₄)₂

Al³⁺+PO₄^3-->AlPO₄

3Ba²⁺+2PO₄^3-->Ba₃(PO₄)₂

3Ni²⁺+2PO₄^3-->Ni₃(PO₄)₂

Ba²⁺+SO₄^2-->BaSO₄

Co²⁺+2OH^-->Co(OH)₂

Cu²⁺+2OH^-->Cu(OH)₂

Al³⁺+3OH^-->Al(OH)₃

Ba²⁺+2OH^-->Ba(OH)₂

Ni²⁺+2OH^-->Ni(OH)₂