Quoting Post Archived Topic: It will not be bumped to the top of the forum. Topic Chemistry help please Membername   Not a member? Sign Up Free (takes 20 seconds) Password   Forgotten your password? Post Font: Verdana Arial Black Georgia Comic Sans Impact   Size: Tiny Normal Big Huge   Color: Default Dark Red Red Orange Brown Green Olive Cyan Blue Dark Blue Indigo Black [ Check Spelling ] [ Post Preview ] [ LiveTags ] Quote: from [m]Z o E[/m] at 12:26 pm on Jan. 2, 2009[quote]isnt it something to do with the ratio of hydrogen to oxygen.[/quote] FAQ Keyword Search: Post Options Favorites Manager Notify me of new replies to this topic by email Notify me of new replies to this topic by private message Original Post Uhhello Posted at 12:25 pm on Jan. 2, 2009 The answer is 5cm but i can't seem to get it...:( 10cm of hydrogen is burnt in oxygen to form water. What volume of oxygen is needed for the hydrogen to burn completely? Thanks for any help :)

Replies Capt Kuchiki Byakuya Posted at 1:41 pm on Jan. 2, 2009 Post from this position was omitted due to content violations Just Waiting Here Posted at 12:35 pm on Jan. 2, 2009 It's really just stoichiometry. H2 + O2 -->  H2O That's the skeletal equation, so you need to balance it. 2H2 + O2 ---> 2H20 So... you need twice as much hydrogen as you do oxygen. Frubeling Posted at 12:31 pm on Jan. 2, 2009 Quote: from Uhhello at 8:30 pm on Jan. 2, 2009 Quote: from Frubeling at 12:29 pm on Jan. 2, 2009 Everyones giving the most simple method, are you expected to use moles? Well i was trying top use like 1 mole of gas occupies 24dm volumne... I think i was over complicating it. Thankyou everyone. You did over complicate it, alot Uhhello Posted at 12:30 pm on Jan. 2, 2009 Quote: from Frubeling at 12:29 pm on Jan. 2, 2009 Everyones giving the most simple method, are you expected to use moles? Well i was trying top use like 1 mole of gas occupies 24dm volumne... I think i was over complicating it. Thankyou everyone. Ndskewll Posted at 12:29 pm on Jan. 2, 2009 Post from this position was omitted due to content violations Frubeling Posted at 12:29 pm on Jan. 2, 2009 Everyones giving the most simple method, are you expected to use moles? Uhhello Posted at 12:29 pm on Jan. 2, 2009 Quote: from yyyt at 12:26 pm on Jan. 2, 2009 do you mean cm cubed? Yea sicosys Posted at 12:28 pm on Jan. 2, 2009 Quote: from Lord Cat at 12:26 pm on Jan. 2, 2009 Well there is twice as much hydrogen then oxygen So if there is 10cm of H then there is 5cm of O I know this is it haha marshmellowman Posted at 12:28 pm on Jan. 2, 2009 The reaction is H2 + 1/2O2 -> H2O So you had 1 mole of Hydrogen + 1/2 mole of Oxygen making one mole of water. Therefore the volume of oxygen will be half the volume of hydrogen needed, 10/2 = 5cm^3. senior09 Posted at 12:27 pm on Jan. 2, 2009 There are two hydrogens so you have to use half of the oxygen Leannbby Posted at 12:27 pm on Jan. 2, 2009 Quote: from Lord Cat at 3:26 pm on Jan. 2, 2009 Well there is twice as much hydrogen then oxygen So if there is 10cm of H then there is 5cm of O im pretty sure thats it Lord Cat Posted at 12:26 pm on Jan. 2, 2009 Well there is twice as much hydrogen then oxygen So if there is 10cm of H then there is 5cm of O wallopwoop Posted at 12:26 pm on Jan. 2, 2009 Dude water's two parts hydrogen and one part oxygen.  Everybody learned that in like kindergarten. Z o E Posted at 12:26 pm on Jan. 2, 2009 isnt it something to do with the ratio of hydrogen to oxygen. agerask Posted at 12:26 pm on Jan. 2, 2009 use dimensional analysis. Most recent 15 of 16 previous replies displayed.