CAIE IGCSE Chemistry Reversible Hydration of Salts
Practise predicting and reversing hydration changes in copper sulfate or cobalt chloride by heating hydrated salts or adding water to anhydrous salts.
- Syllabus
- 2026–2028
- Course
- Chemistry 0620
Exam points
- use heating to remove water from a hydrated salt and form its anhydrous colour
- add water to the anhydrous salt to restore the hydrated form and reverse the change
- identify blue-to-white copper sulfate and pink-to-blue cobalt chloride changes correctly
6.3.2—Changing the conditions can change the question 1
[Maximum number: 1]
Cobalt and copper are transition elements.
Both copper and cobalt can form coloured compounds. Some of these compounds contain water of crystallisation.
State how this colour change can be reversed.
[Total: 14]
heating (the hydrated copper(II) sulfate)
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