decomposition of solids Flashcards
Thermal decomposition is a chemical reaction in which a single compound breaks up to form ____ or more _____ compounds or elements on ______.
Thermal decomposition is a chemical reaction in which a single compound breaks up to form two or more simpler compounds or elements on heating.
When a hydrated salt is heated, its water of crystallisation will be expelled as _____ ______, leaving the ______ salt behind.
When a hydrated salt is heated, its water of crystallisation will be expelled as water vapour, leaving the anhydrous salt behind.
How to tell if water vapour evolved?
Test for water vapour: test with cobalt (II) chloride paper
- turn paper from blue to pink
Water vapour may also be seen at the side of the test tube
The identity of gas liberated during heating provides a clue to the _____ in the solid, while the changes in the colour of the _____ and the colour of ______ formed (when it is hot and cold) provide clues to the _____ in the solid.
The identity of gas liberated during heating provides a clue to the anions in the solid, while the changes in the colour of the solid and the colour of residue formed (when it is hot and cold) provide clues to the cation in the solid.
The more ______ the metal, the more _____ stable the metal compound, hence the ______ the difficulty to decompose the metal compounds.
The more reactive the metal, the more thermally stable the metal compound, hence the greater the difficulty to decompose the metal compounds.
Arrange the metals below from most to least reactive:
Sodium, Potassium, Copper, Magnesium, Lead, Silver, Aluminium
Potassium, Sodium, Magnesium, Aluminium, Lead, Copper, Silver
Zinc carbonate decomposes on heating to form ____ _____ and ______ _____ gas. ____ _____ is _____ when hot and _____ when cooled.
Zinc carbonate decomposes on heating to form zinc oxide and carbon dioxide gas. Zinc oxide is yellow when hot and white when cooled.
