To answer the question "Why should a magnesium ribbon be cleaned before burning in air?":
1. **Remove Impurities:** Cleaning the magnesium ribbon before burning helps remove any impurities or substances that might interfere with the burning process. These impurities could affect the reaction or result in incomplete combustion.
2. **Ensure Accurate Results:** Cleaning the ribbon ensures that the burning process is not affected by any external factors, allowing for a more accurate observation of the reaction. This helps in obtaining reliable data and results in experiments.
3. **Prevent Contamination:** Contaminants on the surface of the magnesium ribbon could potentially lead to unwanted by-products or reactions during combustion. Cleaning the ribbon minimizes the chances of contamination, ensuring a purer reaction.
In summary, cleaning the magnesium ribbon before burning in air is essential to remove impurities, ensure accurate results, and prevent contamination that could affect the combustion process and the outcome of the experiment.
