1. Can you obtain wood from sawdust?
2. Give three examples each of physical and chemical changes
3. How does curd set? Is this change reversible?
4.Differentiate between a physical change and a chemical change
5. What is an irreversible change? Give two examples.
Answers
Answer:
1. no,we can't because Sawdust (or wood shavings) is a by-product or waste product of woodworking operations such as sawing, milling, planing, routing, drilling and sanding. ... Sawdust is the main component of particleboard
2.Examples of chemical changes are burning, cooking, rusting, and rotting.
3.small quantity of curd is added to warm milk. The milk is stirred and is set aside undisturbed for a few hours at a warm place. ... Curd formed from milk cannot be changed into milk again. So, this an irreversible (cannot be reversed) change.
4.Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.
5.Irreversible changes - where the change is made chemically and can't be reversed into its original states. For example: baking a cake.