Question

exam lesson name: chemistry
exam number: 700700rr
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question 20 of 20 :
select the best answer for the question.

1. the law of definite proportions helps explain why water will always

○ a. consist of a particular proportion of hydrogen and oxygen.
○ b. be released or used up in a chemical reaction.
○ c. break down into gas when heated.
○ d. be used as a solvent to dissolve other compounds.
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Explanation:

The law of definite proportions states that a chemical compound always contains exactly the same proportion of elements by mass. For water (\(H_2O\)), this means it always has a fixed ratio of hydrogen to oxygen. Option A matches this concept. Option B relates to conservation of mass or stoichiometry, not definite proportions. Option C is about physical state change (boiling), not elemental proportions. Option D is about water's solvent properties, unrelated to definite proportions.

Answer:

A. consist of a particular proportion of hydrogen and oxygen.