3.80 moles of oxygen are used up in the reaction. How many moles of water are produced

Question

In a combustion reaction, acetylene (c2h2) combines with oxygen to form carbon dioxide and water

 

Answer 1

First, balance the reaction as follows

 

       2 C2H2   +    5 O2   =     4 CO2    +    2 H2O

 

Then, there are 2 moles of water produced every time that 5 moles of oxygen react with 2 moles of acetylene.

 

To find how many moles of water (X moles water) will be formed when 3.8 moles of oxygen are used up in the reaction,

 

 X moles water   =   [2 moles H2O/ 5 moles O2]   *  3.8 moles O2

 X moles water   =   1.52 moles