| Demonstration Experiment on Video Objective: Test for Water in Milk Peter Keusch |
Cobalt(II) chloride solution: 5 g CoCl2 · 6 H20 are dissolved in 60 ml ethanol 99 %.
Hazards and safety precautions:
Safety glasses and protective gloves required. Experimental procedure: Using a petri dish and a hot plate blue crystalline CuSO4 · 5 H20 is heated strongly until it turns white. Three milk shake glasses are filled with milk. Two spatula measures of the white copper sulfate are added to the milk in the first glass while stirring. The milk in the third glass is mixed with a saturated ethanolic solution of CoCl2 · 6 H2O. Results: The milk in the first glass turns greenblue, the milk in the third glass becomes pink. 
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|  When CuSO4 · 5 H20 is heated the water of crystallization is driven off and anhydrous cupric sulfate is formed. White CuSO4 turns blue again if water is present. CoCl2 · 6 H20 is dissolved in ethanol to form a blue chloro complex. When water is added the chloro complex is converted to a pink hexaaqua complex.  Milk consists of 87 % water. Water serves · as a solvent for whey proteins, lactose, minerals and water-soluble vitamines (e.g. vitamine B2 = lactoflavin) · as a dispersing agent for fat and casein · as a medium for chemical reactions. · 3 - 4 % is hydration water bound to protein and lactose crystals. Index of Lecture Experiments 
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