What are characterstics of chemical reaction
Answers
The characteristics of chemical reactions are :
1) Change of colour - When citric acid is added to Potassium permangenate then the purple colour starts discharging .
2)Change of state - When hydrogen(gas) reacts with oxygen(gas) , they form water a liquid
3)Evolution of a gas - When lead nitrate is heated the it decomposes to lead oxide , nitrogen dioxide with oxygen .
4) Formation of a precipitate - When lead nitrate reacts with potassium iodide , it forms a yellow precipitate Lead iodide and potassium nitrate .
5)Change in temperature -
- Exothermic reaction - reaction in which heat is released
When quick lime reacts with water to form slaked lime , it releases a lot of energy .
- Endothermic reaction - reaction in which heat is absorbed
When hydrogen reacts with iodine to form hydrogen iodide , it absorbs a lot of energy .
in a chemical reaction the reactants are transformed into products by chemical process
we can identify it by:
evolution of gas
change in state
change in colour