Physical And Chemical Change Flashcards
What a physical change?
A change in which the chemical compositions of a substance does not change
The change is only temporary
What kind of changes are physical changes?
Temperature Expand Colour (sometimes) Conductivity Phase
What is a temperature physical change?
When heat energy is added to a substance, the average kinetic energy of the particles increases
What is a physical change in which a substance expands?
When the temperature of a substance rises, the speed of the particles increases
They then occupy more volume
How does a substance change colour in a physical change?
Electrons become energised and jump to higher energy levels
When they return to their ordinary energy levels they emit energy
This is perceived in the form of light i.e colour
How does the conductivity of a substance change during a physical change?
If heat energy is added
Particles move more energetically
It is harder for an electrical current to flow
How does a physical change induce a phase change?
If particles are given enough heat energy
They will have enough kinetic energy to overcome the force of attraction that hold them in their lattice
What is the main factor that contributes to a physical change?
Heat energy
What is a chemical change?
When the chemical composition of a substance changes
New substances are formed due to this change
What are the “new substances” formed after a chemical reaction?
The products
What are the original substances in a chemical reaction called?
Reactants
What is a chemical reaction in which new bonds are created called?
Synthesis
What is an example of a synthesis reaction?
The formation of water molecules
How is a chemical reaction shown?
The atomic symbols for each reactant are shown on the left
An arrow indicates a chemical reaction has taken place
The product are represented in the same way in the right
What is the name of a chemical reaction in which bonds are broken?
Decomposition
