Give any two examples where substance become harder on heating and two examples where substance become softer on heating
The two substance on heating become hard are given below:
- When vulcanised rubber is heated it gets solidifies and its chemical composition remain same.
- Egg is made up of proteins ,so when an egg is boiled at high temperature,entropy of it's molecule increases . This increase in entropy causes denaturation of protein present in egg and results in coagulation of proteins. Thus it gets solidified.
- Ice on heating turns into water
- Vegetable ghee on heating turns into liquid.