Phram107.1 First Exam

• milk of magnesia

  Mg(OH)2
• magnesium hydroxide (Milk of Magnesia): antacid, laxative
• magnesium identification

  MgSO4 + NH4Cl → MgCl + (NH4)2SO4
• magnesium acceptance criteria

  
  

  No precipitate formed upon the addition of ammonium chloride 
• magnesium acceptance critera

  no ppt. forms upon addition of ammonium chloride
• milk of magnesia

  - Mg(OH)2

  - antacid
• milk of magnesia acceptance criteria

  NLT 90.0% and NMT 115.0% of 80mg of the labeled amount
• magnesium identification

  MgSO4 + NH4Cl → MgCl + (NH4)2SO4
• magnesium acceptance criteria


  No precipitate formed upon the addition of ammonium chloride
• magnesium identification


  MgSO4 + (NH4)2CO3 → MgCO3↓ + (NH4)2SO4 (white hazy precipitate)
• magnesium acceptance criteria


  A white, hazy precipitate will be produced
• magnesium identification


  MgCO3↓ + Na2HPO4 → MgHPO4↓ + Na2CO3 (white crystalline precipitate)
• magnesium acceptance criteria


  White, crystalline precipitate is yielded
• magnesium identification


  MgHPO4↓ + NH4OH → no rxn
• magnesium acceptance


  No reaction, precipitate formed prior is insoluble with ammonium hydroxide
• sulfate identification


  MgSO4 + BaCl2 → BaSO4 ↓ + MgCl2 (white precipitate)
• sulfate acceptance


  With barium chloride TS, solutions of sulfates yield a white precipitate
• sulfate identification


  BaSO4 ↓ + HNO3 or HCl → ins. ppt.
• sulfate acceptance


  With barium chloride TS, solutions of sulfates yield a white precipitate that is insoluble in hydrochloric acid and in nitric acid
• sulfate identification


  MgSO4 + Pb(CH3COO)2 → Mg(CH3COO)2 + PbSO4 ↓ (white precipitate)
• sulfate acceptance


  With lead acetate TS, neutral solutions of sulfates yield a white precipitat
• sulfate identification


  PbSO4 + NH4(CH3COO) → Pb(CH3COO)2 + (NH4)SO4
• sulfate acceptance


  PbSO4 is soluble to NH4(CH3COO), it can form a solution
• sulfate identification


  MgSO4 + 2HCl → MgCl + H2SO4
• sulfate acceptance


  no precipitate is formed
• impurities test for MgSO4

  - chloride

  - heavy metals
• test for chlorides
• acceptance criteria (chlorides)


  a 1.0g portion shows no ore chloride than corresponds to mL of 0.020N HCl (0.014%)
• test for heavy metals
• acceptance criteria (heavy metals)


  Limit is 0.001%
• pH test acceptance criteria and why

  - 5.0 and 9.2 in solution

  - MgSO4 is slightly acidic
• loss on drying acceptance criteria

  Anhydrous loses NMT 2.0% of its weight
• importance of loss on drying

  measures water absorbed and purity of reagent
• loss on ignition acceptance criteria

  Must only lose about 22.0-28.0% of its weight
• loss on ignition importance

  measures organic matter in a sample
• sodium identification


  K2CO3 + 2NaOH (heat to boiling) → Na2CO3 + 2KOH
• sodium acceptance


  no precipitate formed
• sodium identification


  2NaOH + K2H2Sb2O7 (heat to boiling) → Na2H2Sb2O7 + 2KOH (rub test tube)
• sodium acceptance


  Dense, crystalline precipitate forms
• sodium flame test


  Intense yellow color to nonluminous flame