How many grams of water can be produced the combination of 8 grams of oxygen and 8 grams of hydrogen?

1 Answer
Jul 17, 2016

This is a stoichiometry problem. You have to write a balanced equation out first


As you can see, you need 2 moles of H2 gas and 1 mole of O2 to form 2 moles of H2O.

You are given grams of both hydrogen gas and oxygen. You must find the limiting reagent first. To do this, take the mass of the reactant and convert it into moles.

Now do the mole-to-mole ratio to find out how many moles of #"H"_2"O"# can be produced from each reactant. The reactant to form the least # of moles, is the limiting reagent.

Ex. For #"H"_2(g)#

#"8 grams H"_2 * "1 mole"/(2 "g"/"mole") * ("2 moles H"_2"O")/("2 moles H"_2) = "moles of H"_2"O produced"#

For #"O"_2(g)#

#"8 grams O"_2 * "1 mole"/(32"g"/"mole") * ("2 moles H"_2"O")/"1 mole O"_2 = "moles of H"_2"O produced"#

Once you find the limiting reagent, proceed with finding the mass in grams of #"H"_2"O"# that can be produced and you have your answer.