Reversibility and dynamic equilibria
2 marks · NormalHydrated cobalt(II) chloride can be heated to produce anhydrous cobalt(II) chloride and water. The process is reversible.
State the chemical equation for this reversible reaction, using the correct symbol, and explain what the symbol means.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
CoCl2·6H2O(s) ⇌ CoCl2(s) + 6H2O(l); the symbol ⇌ shows the reaction can go forwards and backwards (it is reversible)
Also accept: CoCl2·6H2O(s) ⇌ CoCl2(s) + 6H2O(g); CoCl2·6H2O (s) ⇌ CoCl2 (s) + 6H2O (g); CoCl2·6H2O (s) ⇌ CoCl2 (s) + 6H2O (l)
Common mistakes: Using → or ← instead of ⇌; Not explaining the meaning of the symbol
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Correct reversible equation using ⇌ symbol
B2 · 1 mark · Explains ⇌ means the reaction is reversible (forward and backward possible)
Worked solution
The symbol ⇌ (double arrow) means the reaction is reversible: it can go both forwards and backwards.