ASVAB · Chemistry

What does the chemical formula H₂O represent, and what do the symbols mean?

Correct answer

Water — two hydrogen atoms bonded to one oxygen atom

A Two hydrogen atoms only
B Water — two hydrogen atoms bonded to one oxygen atom
C Hydrogen peroxide
D Oxygen gas

Why this is the answer

H₂O is the chemical formula for water. The subscript 2 after H means there are two hydrogen atoms, and the O (with an implied subscript of 1) means one oxygen atom, so each water molecule is two hydrogen atoms bonded to one oxygen atom. Hydrogen peroxide is a different compound, H₂O₂ (two hydrogens and two oxygens). Reading chemical formulas — where subscripts give the number of each atom — is a basic chemistry skill. Water's formula H₂O is one of the most important to recognize.

Source: ASVAB GS, Chemical Formulas

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What does the chemical formula H₂O represent, and what do the symbols mean?

Why this is the answer

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