Support Forums Today's Posts

Get Advice Connect with TeenHelp Resources
HelpLINK Facebook     Twitter     Tumblr     Instagram    Hotlines    Safety Zone    Alternatives

You are not registered or have not logged in

Hello guest! (Not a guest? Log in above!)

As a guest on TeenHelp you are only able to use some of our site's features. By registering an account you will be able to enjoy unlimited access to our site, and will be able to:

  • Connect with thousands of teenagers worldwide by actively taking part in our Support Forums and Chat Room.
  • Find others with similar interests in our Social Groups.
  • Express yourself through our Blogs, Picture Albums and User Profiles.
  • And much much more!

Signing up is free, anonymous and will only take a few moments, so click here to register now!

Education and Careers Work of any kind can get stressful at times. Ask in this forum if you need help with coursework, applications, and more.

Closed Thread
Thread Tools Search this Thread Rate Thread
  (#1 (permalink)) Old
Broken one Offline
Junior TeenHelper
Broken one's Avatar
Name: Sian
Age: 27
Gender: Female
Location: UK

Posts: 305
Join Date: November 3rd 2009

Chemistry problem help - February 28th 2010, 10:58 AM

I've been given a question to do and I can not work out how to do it at all...so was wondering if someone could enlighten me please?

"The equations for the combination of gaseous atoms of carbon and hydrogen to form methane and ethane are shown below.
C (g) + 4H (g) --> CH4 (g) Enthalpy change = -1652KJmol-1
2C (g) + 6H (g) --> C2H4 (g) Enthalpy change = -2825KJmol-1

Use these data to calculate:
i. The bond enthalpy of a C-H bond
II. The bond enthalpy of a C=C bond"

  (#2 (permalink)) Old
survivor. :)
I've been here a while
Beautiful Disaster's Avatar
Name: Anna
Age: 27
Gender: Female
Location: UK

Posts: 1,101
Blog Entries: 122
Join Date: February 18th 2010

Re: Chemistry problem help - February 28th 2010, 07:19 PM

In the first equation, you have 4 C-H bonds yeah? Dividing the number by 4 (as you have four of them) I think will give you the answer for part one.

After you have worked it out for one C-H bond, you can work out how much energy from the second equation is the C-H bonds. 2825 - [ 6 x (energy of 1 C-H bond) ] ---- then stick a minus sign in front of it.

I think/hope that's right! If it doesn't make sense then just say and I'll try to explain it again.
Take care.
Closed Thread


chemistry, problem

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Rate This Thread
Rate This Thread:

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All material copyright 1998-2020, TeenHelp.
Terms | Legal | Privacy | Conduct | Complaints | Mobile

Powered by vBulletin®.
Copyright ©2000-2020, Jelsoft Enterprises Ltd.
Search engine optimization by vBSEO.
Theme developed in association with vBStyles.