Substances have different tendencies to donate or accept electrons. When a really good donor meets a great acceptor, the chemical reaction releases a lot of energy. Oxygen (O2) is the best electron acceptor and is used in many aerobic reactions (reactions with oxygen). Hydrogen gas (H2) is a good electron donor.
When O2 and H2 are combined, along with a catalyst, water (H2O) is formed. This example of a redox reaction can be written like this:

Eye protection, fire proof clothing, proper foot gear, just anything that you could prevent yourself from being burned because you are working with flammable materials.
Answer: Fireworks exploding is a chemical change.
Explanation: Lighting gunpowder, and making the explosion is a chemical change.
The bad smelling element is Sulfur, which smells like rotting eggs.
Answer:
Both are similar concepts.
Sound is the vibration of air particles (compression and expansion) the can reach your ears. But you can have vibration being propagated in liquids and solids as well.
Some sounds are generated in structures, so the vibration of a structure is converted to sound in air — for instance, a loudspeaker.
Explanation:
