What mass of water can be produced when #"43.2 g"# of oxygen gas reacts with an excess of hydrogen gas in the reaction #"2H"_2("g") + "O"_2("g")"##rarr##"2H"_2"O"#?

1 Answer

#"48.6 g"# of Water would be produced from #"43.2 g"# of Oxygen.

Explanation:

First, start with a balanced chemical equation:

#"O"_2 + "2H"_2"##rarr##"2H"_2"O"#

Now, some dimensional analysis, or unit cancellations...

#43.2cancel("g O"_2) xx ((1cancel("molO"_2))/(32cancel("g O"_2)))xx((2cancel("molH"_2"O"))/(1cancel("molO"_2)))xx((18"g H"_2"O")/(1cancel("mol H"_2"O")))="48.6 g H"_2"O"#