Question

What is a chemical change?

b) Give the examples of chemical change (one each) which takes place in (i) sugar and (ii) milk.

c) Describe the steps (pointwise) to obtain pure copper sulphate crystals from its hot saturated

solution.​

Answer 1

Answer:

when sugar heated it ill change to carbonate and shows black colour.

when milk is fermented it turns to form curd

Answer 2

Answer:

Ans b - Shugar on heating is chemical change, Boiling Milk is a chemical change.

Step-by-step explanation:

Sugar is made of carbon, hydrogen and oxygen atoms. The heat causes the sugar's atoms to combine with the oxygen in the air, forming new groups of atoms. Energy is released in this chemical reaction in the form of smoke and black soot.

As heat is applied to the milk, the proteins casein and beta-lactoglobulin start to coagulate, and form a skin on the surface. After further heating, the skin dries because of evaporation, and forms a still firmer barrier. Steam produced under the skin builds up and causes the milk to boil over