Chemistry Quiz
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MATTER AND ITS INTERACTIONS
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Iron reacts with oxygen in air to form rust (iron(III) oxide): 4Fe(s)+3O2(g)→2Fe2O3(s)4\text{Fe}(s) + 3\text{O}_2(g) \rightarrow 2\text{Fe}_2\text{O}_3(s) A piece of steel wool has a mass of 20 g. After being left in moist air for several days, the rusted wool has a mass of 27 g. Which statement best explains the mass increase?
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