Given the equation #2H_2O ->2H_2 + O_2#, how many moles of #H_2O# would be required to produce 2.5 moles of #O_2#?

1 Answer
May 16, 2016

Answer:

#5# moles of #H_2O#

Explanation:

Since the chemical equation,

#color(red)2H_2O->2H_2+color(blue)1O_2#

requires a specific number of moles of the reactant, then a specific number of moles of the products are created.

With this knowledge, you can create a mole ratio.

The general format of a mole ratio is as follows:

#color(blue)(|bar(ul(color(white)(a/a)color(black)(("required based on balanced equation")/("product based on balanced equation")=("required")/("product"))color(white)(a/a)|)))#

In your case, you're looking for the moles of #H_2O# required to make #2.5# moles of #O_2#.

Thus, your mole ratio would be:

#(color(red)2color(white)(i)molcolor(white)(i)H_2O)/(color(blue)1color(white)(i)molcolor(white)(i)O_2)=x/(2.5color(white)(i)molcolor(white)(i)O_2)#

#color(darkorange)(rArr)#where #x# represents the moles of #H_2O# required

From this point on, your goal is to solve for #x# to find the moles of #H_2O# required to produce #2.5# moles of #O_2#.

#x=2.5color(purple)cancelcolor(black)(molcolor(white)(i)O_2)xx(2color(white)(i)molcolor(white)(i)H_2O)/(1color(purple)cancelcolor(black)(molcolor(white)(i)O_2))#

#x=color(green)(|bar(ul(color(white)(a/a)5color(white)(i)molcolor(white)(i)H_2Ocolor(white)(a/a)|)))#