A 50 gram nail is left outside. In 1 week it is rusty and now has a mass of 55 grams. How can this be if matter cannot be created or destroyed? simple
The increase in mass of the nail can be explained by the formation of rust. When exposed to the elements, particularly moisture and oxygen, iron undergoes a chemical reaction called oxidation, which causes it to rust.
Rust is the result of the iron combining with oxygen from the air and water molecules. This chemical reaction adds mass to the nail as iron atoms combine with oxygen atoms to form iron oxide (rust). The rust that forms on the surface of the nail adds to its overall mass, which is why it weighs 55 grams after being left outside for a week.
So, matter is not being created or destroyed in this scenario. The original mass of the nail remains the same, but it has gained additional mass due to the presence of rust.