Chemical Changes Flashcards
What is a physical change?
A change which is reversible, in which new substances are not made- e.g. changes of state or dissolving.
What is a chemical change?
A change in which atoms are rearranged to create a new substance. It is irreversible.
What is an endothermic reaction?
A reaction which takes in energy, therefore the surroundings get colder.
What is an exothermic reaction?
A reaction which gives out energy, therefore the surroundings get colder.
What is Thermal decomposition?
The breaking down of a substance using only heat. There is no reaction with oxygen in the air. Usually carbonates thermally decompose into an oxide, plus carbon dioxide.
What are Group 2 carbonates?
Carbonates which can be thermally decomposed with a Bunsen Burner such as calcium, magnesium, copper and zinc.
What are Group 1 carbonates?
Carbonates which need to be heated at a higher temperature than a Bunsen Burner can provide in order to thermally decompose.
What would the equation below produce?
Zinc Carbonate + heat ——>
ZnCO3
Zinc oxide + Carbon dioxide
ZnO) + (CO2
What is oxidation?
A reaction where a substance is burnt in oxygen to form oxides.
What solutions do metal oxide produce?
Alkaline
What solution do non-metal oxide produce?
Acidic
What are displacement reactions?
Some metals are more reactive than others. If a compound contains a metal, a more reactive metal will displace the less reactive one.
What is neutralisation?
One where the acidity or alkalinity of a substance is changed.
What are the features of bases?
- Do not dissolve in water
- All bases are not alkali
- Neautralises acids
What are the features of alkali?
- Bases that dissolve in water
- All alkali are bases
