Question

A chemist mixes oxygen gas and hydrogen gas to form water, which is composed of one oxygen and two hydrogen atoms per molecule. What has occurred?

Answer 1

A chemical change.

Step-by-step explanation:

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Answer 2

When a chemist mixes oxygen gas and hydrogen gas to form water, which is composed of one oxygen and two hydrogen atoms per molecule. The hydrogen and oxygen atoms bounds together by making a bond called covalent bond. In a covalent bond, two atoms are bound together because they each want to "share" each other's electrons.