Baljinder Kaur Solutions for Chapter: Physical and Chemical Changes, Exercise 1: Skill Fill

Take a half a beaker of milk. Heat the milk and now add fresh lemon juice to this milk. Keep heating for sometime. The citric acid present in the lemon coagulates the protein present in the milk. The protein coagulates to form paneer. This change is _____, new compounds are formed from original compounds. Energy in the form of heat is _____. Thus, we can say change of milk to paneer is an example of _____ change.

Take luke warm milk in a beaker. To this milk add a spoon of curd and keep it overnight. Check it in the morning. The milk will change to _____. The chemical reaction taking placs is:

$\mathrm{Lactose} \mathrm{sugar}\underset{\mathrm{Bacteria} \mathrm{present} \mathrm{in} \mathrm{curd}}{\overset{\mathrm{Lactobacillus}}{\to }}\mathrm{Lactic} \mathrm{acid}$