TUTTEE ACADEMY LOGO
broken image
  • Home
  • About Us
  • Subjects 
    • CHEMISTRY
    • BIOLOGY
    • PHYSICS
    • MATHEMATICS
    • PSYCHOLOGY
    • ECONOMICS
    • BUSINESS
    • COMPUTER SCIENCE
    • CHINESE
    • ENGLISH
    • SPANISH
    • IBDP IA / EE
    • IBDP TOK
    • ONLINE TUTORIAL
  • Exam Boards 
    • IBDP
    • IBMYP
    • IGCSE & GCSE
    • HKDSE
    • GCE A-LEVELS
  • Courses 
    • IBDP Tuition
    • GCE A-Level Tuition
    • IBMYP Tuition
    • I/GCSE Tuition
    • HKDSE Tuition
  • Admission Test Prep 
    • PREDICTED GRADE
    • SAT / SSAT
    • UKISET (UK)
    • BMAT
    • UKCAT / UCAT
    • LNAT
    • TMUA (Cambridge)
  • Student Results 
    • IBDP STUDENT RESULTS
    • IGCSE & GCSE MATHEMATICS
    • A-LEVEL STUDENT RESULTS
    • IGCSE STUDENT RESULTS
    • GCSE STUDENT RESULTS (UK)
    • HKDSE STUDENT RESULTS
    • OUR STORIES
  • Question Bank
  • Resources
SCHEDULE A LESSON NOW

AS/A-level Chemistry - Born-Haber Cycle

Physical Chemistry, Born-Haber Cycle, Lattice Enthalpy

· AS Chemistry,A-level Chemistry,Physical chemistry,Born-Haber Cycle,Lattice Enthalpy

Lattice Enthalpy

  • Lattice enthalpy represents the enthalpy change when the ions in one mole of a solid ionic compound are broken apart (lattice enthalpy of dissociation) or brought together (lattice enthalpy of formation).
  • The lattice enthalpy of a compound is a indication of the strength of the ionic bonding the greater the magnitude of the lattice enthalpy, the stronger the bonding. 
  • Generally speaking, compounds with smaller ions and/ or ions with higher charges have stronger attractions and so greater lattice enthalpy.
  • eg. NaCl has a higher lattice enthalpy (stronger ionic bonding) than KCl as the Na+ ion is smaller than the K+ ion
Measuring Lattice enthalpy
  • using Born-Haber cycle, this value is often called the 'experimental value' as the data used in the Born-Haber cycle is determined by experiments.
  • A Born-Haber Cycle is a cycle that included all the enthalpy changes in the formation of an ionic compound. 
Drawing Born-Haber cycles:
  • Draw a separate step for every enthalpy change (eg. for atomisaton of the metal atoms separately from the non-metal atoms, for each individual ionisation enthalpy, for each individual electron affinity) 
  • second and third electron affinities are endothermic and show be drawn going up 👆not down 
  • In AS/A-level Chemistry exam, it is best to write the numerical values of the enthalpy changes on each step to prevent mistakes! 👩‍🏫
  • The arrows pointing upwards represent endothermic changes👆🏻, those pointing downwards show exothermic changes👇🏻.
  • From the Born-Haber Cycle, the enthalpy change associated with the route depicted by the blue arrow is equal to the enthalpy change of the route shown by the red arrow.
broken image

Example: Find the lattice enthalpy formation of NaCl.

 Na+(g) + Cl-(g) ➔ NaCl(s)

broken image

Input the appropriate values to the corresponding enthalpy change. The Born-Haber cycle for NaCl is shown below:

broken image

So, from the cycle:

broken image

This types of question will definitely appear in AS/A-level Chemistry exam, it may look difficult but practice makes perfect! You can do it!🙌

This is the end of the topic!

broken image

CLICK HERE TO LEARN MORE ABOUT OUR A-LEVEL CHEMISTRY COURSES

SIGN UP FOR A FREE A-LEVEL CHEMISTRY TRIAL

Drafted by Cherry (Chemistry)

Subscribe
Previous
IBDP Biology - Proteins
Next
I/GCSE Biology - Protein Synthesis
 Return to site
Profile picture
Cancel
Cookie Use
We use cookies to improve browsing experience, security, and data collection. By accepting, you agree to the use of cookies for advertising and analytics. You can change your cookie settings at any time. Learn More
Accept all
Settings
Decline All
Cookie Settings
Necessary Cookies
These cookies enable core functionality such as security, network management, and accessibility. These cookies can’t be switched off.
Analytics Cookies
These cookies help us better understand how visitors interact with our website and help us discover errors.
Preferences Cookies
These cookies allow the website to remember choices you've made to provide enhanced functionality and personalization.
Save