Answer:
6 invertible mole ratios (12 in total).
Explanation:
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In this case, according to the balanced chemical reaction, it is possible to realize that methane would have 1:2, 1:1 and 1:2 mole ratios with oxygen, carbon dioxide and water respectively, oxygen would have 2:1 and 2:2 mole ratios with carbon dioxide and water respectively and finally, there is a 1:2 mole ratio between carbon dioxide and water, therefore there are 6 mole ratios that we can use for any stoichiometric calculations.
By the way, this mole ratios can be inverted depending on the given amount and the required one.
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