In basic chemistry, which option correctly states the molecular composition of water (H2O)?
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AOne hydrogen atom and one oxygen atom
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BTwo hydrogen atoms and one oxygen atom
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COne hydrogen atom and two oxygen atoms
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DThree hydrogen atoms and two oxygen atoms
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ETwo hydrogen atoms and three oxygen atoms
Answer
Correct Answer: Two hydrogen atoms and one oxygen atom
Explanation
Introduction:Knowing the composition of common compounds is foundational. Water, central to environmental and hydrologic processes, has a well-known molecular formula that determines many of its unique physical properties.
Given Data / Assumptions:
- We must map the formula H2O to a plain-English atom count.
- No ionized or radical forms are implied.
Concept / Approach:In a chemical formula, subscripts denote atom counts in a single molecule. Thus H2O indicates 2 hydrogen (H) atoms bonded to 1 oxygen (O) atom via polar covalent bonds, enabling hydrogen bonding among molecules.
Step-by-Step Solution:Read H2O → two H atoms, one O atom.Translate to words: two hydrogens and one oxygen.Select the option that states this composition verbatim.
Verification / Alternative check:Molar mass check: 2*1 + 16 = 18 g/mol matches tabulated water data.
Why Other Options Are Wrong:
- HO, HO2, H3O2, H2O3 represent different (often unstable or different) species, not water.
Common Pitfalls:
- Confusing water (H2O) with hydrogen peroxide (H2O2).
Final Answer:Two hydrogen atoms and one oxygen atom.