How is burning magnesium similar to burning methane?

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?

If 16.00g of hydrogen gas reacts with 126.73g of oxygen, how many grams of water are yielded? (both reactants are completely consumed in the reaction.)

Atoms contain subatomic particles called protons and neutrons. when these protons and neutrons spilt, a lot of energy is released