The answer choices:
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[B]: rusting iron ; AND:
[D]: rubbing a marker on paper;
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are BOTH examples of a chemical reaction.
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Note: Rusting iron is, more specifically, a "redox" (or, "oxidation/reduction") reaction.
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An element is a form of matter that is made of only one type of atom
Divide by the molar mass of HCl which is 36.5g/mol grams cancels out and you are left with 1.99 mol.