Blue crystals turn white at heating and turn blue again after adding water.
name: Demonstration of the dehydration of hydrated copper (II) sulfate.
Dehydration of Copper (II) Sulfate pentahydrate CuH10O9S - Physical vs Chemical Change
by Sci Higg
Chemical Reactions - Heating of Copper Sulphate - OLabs - Amrita University
CuSO4 pentahydrate hydrated dehydrated anhydrous 3
by Orval Wigger
Thermal Decomposition of Copper(II) Sulfate Pentahydrate
by Yeo Yong Kiat
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CuSO4*5H2O → CuSO4 + 5H2O
- Put a few grams of copper sulfate pentahydrate into a test-tube. Secure obliquely this test-tube with a clamp.
- Close the test-tube with a stopper with a delivery tube. put The end of the delivery tube in the second test-tube. The second test-tube should be placed in a cold water bath (beaker filled with cold water).
- Heat the test-tube with a burner. Move the flame time-to-time to heat the whole test-tube and avoid condensation of the water vapours.
- Copper sulfate turns from blue to white. Water from the hydrate collects in the second test-tube.
- After the whole copper sulfate sample becomes white, stop heating. Slowly add collected water to the obtained anhydrous copper sulfate, it turns blue again.
Copper sulfate pentahydrate CuSO45H2O is a blue colored substance. When heated it turns to pale blue copper trihydrate CuSO43H2O, and then to white copper monohydrate CuSO4*H2O. After the heating is over 250 °C all molecules of water are removed. After the addition of water, copper sulfate hydrates are formed again.