A silver spoon tarnishing Blowing a dandelion Building a sand-castle toasting bread which of these are a chemical change and physical change

Answer 1

To classify these activities as chemical or physical changes:

1. A silver spoon tarnishing: This is a chemical change. The tarnishing process involves a reaction between silver and sulfur compounds in the air, resulting in the formation of silver sulfide.

2. Blowing a dandelion: This is a physical change. Blowing a dandelion disperses its seeds, but the seeds themselves do not undergo any chemical transformation.

3. Building a sandcastle: This is a physical change. The sand is simply being reshaped or restructured without any change to its chemical composition.

4. Toasting bread: This is a chemical change. The process of toasting alters the chemical structure of the bread as it undergoes Maillard reaction, resulting in a change in flavor and color.

In summary:

• Chemical Changes: A silver spoon tarnishing, toasting bread
• Physical Changes: Blowing a dandelion, building a sandcastle