Classify the following changes as physical or chemical: Burning paper, folding paper, photosynthesis, cooking an egg, milk to curd, melting ice, boiling petroleum, fruits ripening.

Here is the classification of each change:

a) Burning a Paper: Chemical change (new substances like ash and smoke are formed).

b) Folding a Paper: Physical change (only the shape of the paper changes, no new substance is formed).

c) Photosynthesis: Chemical change (carbon dioxide and water are converted into glucose and oxygen).

d) Cooking an egg: Chemical change (proteins in the egg undergo denaturation, forming new substances).

e) Milk to curd: Chemical change (lactose in milk is converted to lactic acid, causing milk proteins to coagulate).

f) Melting of ice: Physical change (ice changes from solid to liquid water, but it is still water).

g) Boiling of Petroleum: Physical change (petroleum components are separated by boiling point, but no new substances are formed).

h) Fruits Ripening: Chemical change (complex carbohydrates break down into simpler sugars, and other chemical reactions occur).