Group Members Yao and Chris

Silver... yeah.


Untitled from Chris Trennepohl on Vimeo.

Chemistry Background Information:

0.8M KOH
.8 mol/L * 56.11 g/mol * .45 L = 20.20g KOH in 450 mL
0.1M AgNO3
.1 mol/L * 109.87 g/mol * .9 L = 15.29g AgNO3 in 900 mL
0.5M dextrose, C6H12O6
.5 mol/L * 180.18 g/mol * .3 L = 27.03g C6H12O6 in 300 mL

Silver Solution
AgNO3(aq) + NH4OH(aq) ---> AgOH(s) + NH4+(aq) + NO3-(aq)

Ag+(aq) + 2 NH3(aq) ---> Ag(NH3)2+(aq)

Ag(NH3)2+(aq) + KOH(aq) ---> AgOH(s) + K+(aq) + NH3(aq)

The sugar complexes in solution to form a aldehyde, CH20H(CHOH)4CHO.
2Ag(NH3)2+(aq) + CH2OH(CHOH)4CHO(aq) + 3OH- ---> 2Ag(s) + CH2OH(CHOH)4COO- + 4NH3(aq) + 2H2O(l)
The aldehyde is oxydized in reaction to an acid, as well as reducing the ammonia complex to ammonia, water, and silver solid.

external image Aldehyde-skeletal.png
The reactant used is called Tollen's reagent which is formed by adding KOH to AgNH3, forming a soluble compound, AgOH. Strong aqueous ammonia is added to form the soluble complex, Ag(NH3)2+ (aq). This reagent will convert aldehydes to carboxylic acids (in this reaction, CH2OH(CHOH)4CHO(aq) formed in the sugar water), without attacking carbon-carbon double-bonds.

Note: 15M aqueous ammonia does not smell good. Avoid. Thank You.

Additional Resources:** rapid reaction Tollen's reagent and aldehydes