Which process is an example of a chemical change?
• steam rising from a boiling pot of soup
• a metal railing rusting in damp weather
• alcohol evaporating from a cotton swab
• a piece of wood shrinking as it dries out
A metal railing rusting in damp weather is an example of a chemical change.
The process of a metal railing rusting in damp weather is an example of a chemical change.
To determine which process is an example of a chemical change among the given options, we need to understand what a chemical change is. A chemical change occurs when one or more substances are transformed into different substances with different chemical properties.
Now, let's examine each option and determine if it involves a chemical change:
1. Steam rising from a boiling pot of soup: This process is an example of a physical change, not a chemical change. The liquid water is simply changing to a gaseous state, but its chemical composition remains the same.
2. A metal railing rusting in damp weather: This process is indeed an example of a chemical change. Rust is the product of a chemical reaction between iron and oxygen in the presence of water, resulting in the formation of iron oxide (rust).
3. Alcohol evaporating from a cotton swab: This process is another example of a physical change. The alcohol is transitioning from a liquid to a gaseous state, but its chemical composition remains unchanged.
4. A piece of wood shrinking as it dries out: This process is primarily a physical change. As the wood loses moisture, it undergoes physical changes such as shrinking or cracking. However, some chemical changes may also occur during the drying process, such as the breakdown of complex organic compounds present in the wood.
Therefore, the correct answer is "a metal railing rusting in damp weather" as it involves a chemical change.