How many grams of water could be made from 5.0 mol #H_2# and 3.0 mol #O_2#?

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Answer 1 · 2017-03-27T08:03:47

You need a stoichiometric equation to represent the formation of water:

#H_2(g) + 1/2O_2(g) rarr H_2O(l)#

Given the stoichiometry, dihydrogen is in deficiency, and ONLY #2.5*mol# dioxygen will react to give #5 *mol# water.

And this represents a mass of #5*cancel(mol)xx18.01*g*cancel(mol^-1)=90*g#.

What mas of dioxygen will remain after reaction?

Answer 2 · 2017-03-27T09:55:48

90 g

The balanced equation is: #2H_2(g) + O_2(g) -> 2H_2O(l)#

From this you can see that 5 moles of hydrogen gas would react with 2.5 of the available 3 moles of oxygen gas, to form 5 moles of water.

The molar mass of water is 18 g/mol, so you would end up with 5 x 18 = 90 g of water.