Here are the three phases to solving any stoichiometry problem.

Phase 1: Convert to moles.

Phase 2: Use the coefficients for your molar ratio.

Phase 3: Convert to desired units.

Since you are now an expert on the synthesis of water, work on a couple more practice problems. Make sure that you go through each of the three phases of stoichiometry, even if Phase 1 and/or Phase 3 do not require any dimensional analysis.

1. How many moles of oxygen gas are required to produce 333 grams of water when reacted with hydrogen?

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   Check Your Answer

   
   
   In this problem, you had to do a conversion for Phase 1, but since you wanted moles of oxygen gas, Phase 3 did not require an extra step in dimensional analysis.

2. How many grams of hydrogen gas are required to react with 4.75 moles of oxygen gas?

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   Check Your Answer

   
   
   In this problem, no step in dimensional analysis was required for Phase 1 because you were given moles to start with. In Phase 3, you used molar mass to solve for your desired unit of grams.