evidence of chemical change

:(

physical change

• Freezing

• Boiling

• Condensing

• Evaporating

• Melting

• Dissolving

chemical change

• Gas Bubbles Appear

• Formation of a Precipitate

• Colour Change

• Temperature Change

• Production of Light

• Change in Smell or Taste

system

process of reaction taking place

surroundings

everything around/but the system

endothermic reaction

• system gains heat from surroundings

• energy enters the system

• temperature of the surroundings decreases (gets cold)

exothermic reaction

• system releases heat into surroundings

• temperature of the surroundings increases (gets warm)

• energy exits the system

bond breaking

• endothermic process

• energy is taken in from surroundings to break the chemical bonds

• heat energy taken from surroundings

• high energy and unstable

bond making

• exothermic process

• energy is transferred to the surroundings to make new bonds

• heat energy released to surroundings

• stable