Using qualitative analysis, two cations in an unknown solution was identified. After repeated mixing, centrifugation, and decanting, lead was confirmed in Part A and barium in Part B. In Part C, different colored flames of metal species were observed using cation flame tests. Formula unit, total ionic, and net ionic equations were then composed for the identified cations. If the experiment were to be repeated, step 13 could be ommitted as barium was already confirmed in step 12 with the formation of yellow percipitate barium chromate, and calcium was not confirmed with step 14 when a white percipitate calcium oxalate was not present One of four different solutions were distributed to the students in which two unknown cations in a specific solution were to be
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To balance a centrifuge means to put equal weight/mass across the samples. If the centrifuge is not properly balanced, the speed may be affected and damage the centrifuge. Flame tests can be utilized to effectively identify cations in an unknown solution as different cations display specific colors and thus can act as visual cue to hint at what metal ions are present. However a main limitation to using cation flame tests is that the dissolved metal species have to be pure as impurtites can alter the color results. In addition, some metals may produce the same color and thus can not differentiate all metals.
Lead confirmed: Formula Unit: PbCl2(aq) + K2CrO4(aq) → PbCrO4(s) + 2KCl(aq)
Total ionic: Pb^2+(aq) + 2Cl-(aq) + 2K+(aq) +CrO4^2-(aq) → PbCrO4(s) + 2K+(aq) + 2Cl-(aq)
Net ionic: Pb^2+(aq) + CrO4^2-(aq) → PbCrO4(s)
Barium confirmed: Formula Unit: BaCl2(aq) + H2SO4(aq) → BaSO4(s) + 2HCl(aq)
Total ionic: Ba^2+(aq) + 2Cl-(aq) + 2H+(aq) + SO4^2-(aq) → BaSO4(s) + 2H+(aq) +2Cl-(aq)
Net ionic: Ba^2+(aq) + SO4^2-(aq) →
To balance a centrifuge means to put equal weight/mass across the samples. If the centrifuge is not properly balanced, the speed may be affected and damage the centrifuge. Flame tests can be utilized to effectively identify cations in an unknown solution as different cations display specific colors and thus can act as visual cue to hint at what metal ions are present. However a main limitation to using cation flame tests is that the dissolved metal species have to be pure as impurtites can alter the color results. In addition, some metals may produce the same color and thus can not differentiate all metals.
Lead confirmed: Formula Unit: PbCl2(aq) + K2CrO4(aq) → PbCrO4(s) + 2KCl(aq)
Total ionic: Pb^2+(aq) + 2Cl-(aq) + 2K+(aq) +CrO4^2-(aq) → PbCrO4(s) + 2K+(aq) + 2Cl-(aq)
Net ionic: Pb^2+(aq) + CrO4^2-(aq) → PbCrO4(s)
Barium confirmed: Formula Unit: BaCl2(aq) + H2SO4(aq) → BaSO4(s) + 2HCl(aq)
Total ionic: Ba^2+(aq) + 2Cl-(aq) + 2H+(aq) + SO4^2-(aq) → BaSO4(s) + 2H+(aq) +2Cl-(aq)
Net ionic: Ba^2+(aq) + SO4^2-(aq) →