Classify the following as chemical or physical changes:
(i) cutting of trees.

(ii) melting of butter in a pan.

(iii) rusting of almirah.

(iv) boiling of water to form steam.

(v) passing of electric current, through water and the water breaking down into hydrogen and oxygen gases.

(vi) dissolving common salt in water.

(vii) making a fruit salad with raw fruits, and

(viii) burning of paper and wood.

Which separation techniques will you apply for the separation of the following?

Different pigments from an extract of flower petals.

Which separation techniques will you apply for the separation of the following?

Butter from curd.

Write the steps you would use for making tea. Use the words—solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution).

Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.