water
When you combine one Oxygen and one Hydrogen you get Hydroxide. If you combine one Oxygen with two hydrogens you will end up with water.
When hydrogen and oxygen combine to form water, water is a product of the reaction.
methane
Methane is correct
Magnesium Hydrogen
The compound oxygen and hydrogen can combine explosively to form water.
water
You can get water from hydrogen if you combine the hydrogen with oxygen atoms.
No. Hydrogen combines with oxygen to make water.
That would be a compound. Combine the elements of hydrogen and oxygen, and get a compound (water) that is quite different from the two gasses you started with.
Many chemical elements combine with oxygen; the reaction with oxygen is called oxydation.
Hydrogen and oxygen combine explosively in a single reaction.