Physical and chemical change Flashcards
1
Q
Physical change
A
- No new substances are formed
- Energy changes are small compared to chemical change
- The mass, number of atoms and molecules are being conserved
2
Q
Rearrangement of molecules during physical changes
A
Molecules separate when water evaporates to form water vapour.
When ice melts molecules become disorderly arranged due to breaking of intermolecular forces.
3
Q
Chemical change
A
- New chemical substances are formed, new chemical composition
- Energy changes are much larger than those of physical change
- Mass and atoms are conserved, but the number of molecules is not
4
Q
Types of chemical reactions
A
- Synthesis reactions
- Decomposition reactions
- Ion-exchange reactions
5
Q
The Law of Conservation of Matter
A
During a chemical reaction
The number of atoms of reactants = number of atoms of product.
or
The total mass of all reactants = total mass of all products.
