Unknown 9
CHM 2046 L
Scheme of Analysis for Unknown 9A/9B
“Fair Game” Unknowns * Cations: Na+, K+, NH4+, Ca2+, Mg(H2O)62+, Al(H2O)63+, Zn(H2O)62+, Cu(H2O)2+, Ag(H2O)+ * Anions: Cl-, NO3-, SO4-2, HSO4-, OH-, CO3-2, HCO3-, S-2 * Insoluble Salts: Ca(OH)2, CaCO3, CaSO4, Mg(OH)2, MgCO3, Ag2O, AgCl, Ag2S, CuO, CuCO3, CuS, Zn(OH)2, ZnCO3, ZnS * Alums: [Al(OH2)6]2(SO4)3∙6H2O, Na[Al(OH2)6](SO4)2∙6H2O, K[Al(OH2)6](SO4)2∙6H2O, NH4[Al(OH2)6]2(SO4)2∙6H2O * Hydrated Ions: Na2CO3∙10H2O, Na2SO4∙10H2O, Ca(OH2)6Cl2, Mg(OH2)6Cl2, Mg(OH2)6(NO3)2, Mg(OH2)6SO4∙H2O, Al(OH2)6Cl3 * Note: Sample 9A is a guaranteed pure salt, unless it is an alum.
Procedure of Analysis for Sample 9A/9B
* Describe sample, noting color, shape, and odor.
Test on Original Sample
* Flame Test (Remember to clean with 16 M HONO2 in between each test) * Orange flame indicates presence of Na+, with K+, Ca2+, and NH4+ as possibilities. * Purple flame indicates presence of K+, with NH4+ as a possibility. No Na+ is present. * Red flame indicates presence of Ca2+, with K+ as a possibility. No Na+ is present. * Green flame indicates presence of Cu2+, with other ions as possibilities. No Na+ is present. * No color indicates presence of NH4+, Al3+, or Mg2+. No Na+, K+, or Ca2+ is present.
* NH4+ Test * Method I * Place portion of sample in test tube and add 1 M NaOH, and then suspend a piece of red litmus paper over the tube. Remember to add a drop of deionized water to the paper before hovering over the tube. If it turns blue, NH4+ is present. * Method II * Place portion of sample in a crucible and heat. If gray fumes and smoke are emitted, then NH4+ is present.
* K+ Test * If NH4+ is present, then place small portion of the same in a crucible and heat strongly until fumes and smokes are no longer discharged. Next, dissolve any residue in 1-2 mL of deionized water and place in a spot plate. Add a drop of 6M HAc and 2-3 drops of sodium
Scheme of Analysis for Unknown 9A/9B
“Fair Game” Unknowns * Cations: Na+, K+, NH4+, Ca2+, Mg(H2O)62+, Al(H2O)63+, Zn(H2O)62+, Cu(H2O)2+, Ag(H2O)+ * Anions: Cl-, NO3-, SO4-2, HSO4-, OH-, CO3-2, HCO3-, S-2 * Insoluble Salts: Ca(OH)2, CaCO3, CaSO4, Mg(OH)2, MgCO3, Ag2O, AgCl, Ag2S, CuO, CuCO3, CuS, Zn(OH)2, ZnCO3, ZnS * Alums: [Al(OH2)6]2(SO4)3∙6H2O, Na[Al(OH2)6](SO4)2∙6H2O, K[Al(OH2)6](SO4)2∙6H2O, NH4[Al(OH2)6]2(SO4)2∙6H2O * Hydrated Ions: Na2CO3∙10H2O, Na2SO4∙10H2O, Ca(OH2)6Cl2, Mg(OH2)6Cl2, Mg(OH2)6(NO3)2, Mg(OH2)6SO4∙H2O, Al(OH2)6Cl3 * Note: Sample 9A is a guaranteed pure salt, unless it is an alum.
Procedure of Analysis for Sample 9A/9B
* Describe sample, noting color, shape, and odor.
Test on Original Sample
* Flame Test (Remember to clean with 16 M HONO2 in between each test) * Orange flame indicates presence of Na+, with K+, Ca2+, and NH4+ as possibilities. * Purple flame indicates presence of K+, with NH4+ as a possibility. No Na+ is present. * Red flame indicates presence of Ca2+, with K+ as a possibility. No Na+ is present. * Green flame indicates presence of Cu2+, with other ions as possibilities. No Na+ is present. * No color indicates presence of NH4+, Al3+, or Mg2+. No Na+, K+, or Ca2+ is present.
* NH4+ Test * Method I * Place portion of sample in test tube and add 1 M NaOH, and then suspend a piece of red litmus paper over the tube. Remember to add a drop of deionized water to the paper before hovering over the tube. If it turns blue, NH4+ is present. * Method II * Place portion of sample in a crucible and heat. If gray fumes and smoke are emitted, then NH4+ is present.
* K+ Test * If NH4+ is present, then place small portion of the same in a crucible and heat strongly until fumes and smokes are no longer discharged. Next, dissolve any residue in 1-2 mL of deionized water and place in a spot plate. Add a drop of 6M HAc and 2-3 drops of sodium