Hey! Sign in to get help with your study questionsNew here? Join for free to post

Combustion and alkanes

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
    • Thread Starter


    I would appreciate it if someone could clarify whether these statements are true, 'the longer the chain length of the hydrocarbon, the less easily it combusts' and the longer carbon chain length the more energy that is released on combustion.

    Sorry you've not had any responses about this. Are you sure you've posted in the right place? Here's a link to our subject forum which should help get you more responses if you post there.

    You can also find the Exam Thread list for A-levels here and GCSE here. :dumbells:

    Just quoting in Puddles the Monkey so she can move the thread if needed
    (Original post by Puddles the Monkey)

    The first statement is correct as the longer the hydrocarbon chain, the more bonds there are between the hydrogen and carbon atoms. This means that for combustion to occur more bonds must be broken and more atoms reacted in a longer chain hydrocarbon, Therefore the longer the hydrocarbon chain, the harder it is to combust.

    The second statement is also correct as the more bonds that are broken (more bonds in larger hydrocarbon) the more energy is released. As combustion is a exothermic reaction (it releases energy into the environment), the more bonds there are, the more energy is released. Therefore the longer the hydrocarbon chain, the more is released to the surroundings.


    Posted from TSR Mobile

    Yeah, more points of contact. More London forces, more energy required to combust.
    If there is branching less points of contact, less London forces therfore easier to combust
Write a reply…


Submit reply


Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. Oops, you need to agree to our Ts&Cs to register
  2. Slide to join now Processing…

Updated: June 3, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

I want...

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.