Hi guys, I have been solving many stoichiometry problems but their is something I can do but I don't fully understand why it works it kinda confuses me atleast on mathematical level. I don't like doing something I don't fully understand. What I don't understand is if we have for example a chemical formula of burning hydrocarbons in O2. CxHx(g) + O2(g) ---> CO2(g) + H2O(l) Now what I don't understand is if we get the number of moles that is contained in water and we want after that to get the number of moles in Hydrogen that is contained inside this water why do we have to multiply by two ? didn't we already got the number of moles that is contained in water why do we have to recalculate it ? My intuition tells me that we did multiply it by 2 in order to get the number of moles that needs to react with O to form 1 mole of H2O is that correct or wrong ? This question may seem stupid,but I am self learning chemistry so some books doesn't explain something fully. Thanks.