8 Solution Shuffle
Purpose: To design and carry out an experiment to determine the specific identity of the compound in each of the numbered 8 vials. Solutions are: BaCl2, CaCo3, Ca(OH)2, KI, NaCl, NaHCO3, Na2SO4, Pb(NO3)2.
8 unknown substances
Small stirring rod or toothpick
1. Place each unknown substance into individual wells.
2. Determine solubility of each substance by adding distilled water to each well. Stir well and record observations.
3. Use HCl as an additional test to help determine the unknown substances.
4. Get more of each unknown substance and place again in individual wells. Instead of adding distilled water, mix unknowns with HCl. Record observations for each substance.
5. Use solubility rules to determine the identities of each unknown substance.
6. To ensure correct identities, mix unknown substances with each other. Knowledge of chemical reactions will help support our conclusion.
7. Clean lab station.
8. Justify answers with supportive observations.
Solubility of Unknowns with Water
Unknown Substances Solubility/Observations
A Completely soluble
B Slightly soluble
C Not soluble
D Completely soluble
E Completely soluble
F Slightly soluble
G Very slightly soluble
H Completely soluble
Solubility of Unknowns with HCl
Unknown Substances Solubility/ Observations
B Bubbled, PPT
C Slightly dissolved
D No change
E Slightly dissolved
F Marginally dissolved
G Bubbles, dissolved
H Light yellow
Vial Contains Justification
A Na2So4 Soluble with water and HCl, no PPT when mixed with KI
B CaCO3 White with water, bubbles with HCl (Same results as NaHCO3)
C Pb(NO3)2 Soluble with water and HCl; PPT when mixed with KI
D BaCl2 Soluble with water, no change with HCl; PPT when mixed with Na2SO4 and NaCl
E NaCl Soluble with water, no change with HCl; PPT when mixed with Na2SO4 and BaCl2