Q6 If you leave a piece of iron in the open for a few days, it acquires a film of brownish
substance.
5(1+2+1
(a) Why does this happen?
(b) Is it a physical or a chemical change? Explain.
(c) How can this change be prevented?
(d) Give two other examples of a similar type of change.
Answers
Answer:
(a) Iron reacts with moisture present in air and starts rusting.
(b) THIS IS A CHEMICAL CHANGE Because chemical changes were not be converted into their previous forms easily.
(c) THIS CHANGE CAN BR PREVENTED if we kept them in a moisture proof or Air tight container.
Answer:
Here is the answer
Explanation:
1. Rust is a general term for a series of iron oxides, usually, red oxides, formed by the reaction of iron with oxygen in the presence of water or air moisture.
Rusting is the common term for corrosion of iron and its alloys, such as steel.
Water is usually present in the form of water vapour and oxygen is always present in the normal atmosphere.
The oxygen needs moisture as a catalyst and reactant to accelerate the reaction, so in the absence of moisture, iron won't rust.
So both water and oxygen are required to form rust from metal iron.
2.Rusting is an example of a chemical change. ... However, unlike physical properties, chemical properties can only be observed as the substance is in the process of being changed into a different substance. A chemical change is also called a chemical reaction.
3. Paint the bare metal with any durable acrylic paint. Do not use water-soluable paints, since they will only worsen the rust. Rust will form underneath this type of paint , Coat it with Oil - Use of oil or grease significantly reduces the chances of developing rust in iron,etc..
4 . Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding.
Hope this help u