State whether the following statements are true or false. In case a statement is false, write the corrected statement in your notebook.
- Cutting a log of wood into pieces is a chemical change. (True/False)
- Formation of manure from leaves is a physical change. (True/False)
- Iron pipes coated with zinc do not get rusted easily. (True/False)
- Iron and rust are the same substances. (True/False)
- Condensation of steam is not a chemical change. (True/False)
Answer:
(a) Cutting a log of wood into pieces is a physical change as it results in the formation of no new substances , and no changes in the chemical properties of wood.
- Hence, the statement is false.
(b) Formation of manure from leaves is a chemical change. It is irreversible , and a new substance (manure) is formed.
- Hence, the statement is false .
(c) Iron pipes coated with zinc do not get rusted easily. The process is called Galvanisation . It is used to prevent iron pipes from rusting .
- Hence, the statement is true .
(d) Iron reacts with water and oxygen to form Iron Oxide . This Iron Oxide (reddish brown in colour is known as Rust .
- Hence, the statement is false .
(e) Condensation of steam is a physical change as water only changes its state , and the process is reversible .
- Hence, the statement is true .
