Energy Cycles

15.1 Energy cycles

Understandings

Representative equations (e.g. M+(g) M+(aq)) can be used for enthalpy/energy of hydration, ionization, atomization, electron affi nity, lattice, covalent bond, and solution.
Enthalpy of solution, hydration enthalpy, and lattice enthalpy are related in an energy cycle.

Applications and skills

Construction of Born–Haber cycles for Group 1 and 2 oxides and chlorides.
Construction of energy cycles from hydration, lattice, and solution enthalpy. For example, dissolution of solid NaOH or NH4Cl in water.
Calculation of enthalpy changes from Born–Haber or dissolution energy cycles. Guidance: The following enthalpy/energy terms should be covered: ionization, atomization, electron affinity lattice, covalent bond, hydration, and solution. Values for lattice enthalpies (section 18), enthalpies of aqueous solutions (section 19), and enthalpies of hydration (section 20) are given in the data booklet.
Relate size and charge of ions to lattice and hydration enthalpies. Guidance: Polarizing effect of some ions producing covalent character in some largely ionic substances will not be assessed.
Perform lab experiments which could include single replacement reactions in aqueous solutions.

Inquiry questions

15.1 In what why are energy cycles using Hess's law?

Get Access

Born Haber cycle

Watch the video about the born haber cycle and how to calculate the lattice enthalpy using the born haber cycle.

Now try it yourself using the example below:
1. Calculate the lattice enthalpy of magnesium oxide using the data in your data booklet section 8-11 and the data below:
Additional data:
• enthalpy change of atomization for Mg(s) = +148 kJ mol–1
• second ionization energy of magnesium = +1451 kJ mol–1
• enthalpy change of formation of MgO(s) = –602 kJ mol–1

2. Make a visual poster of the process and your calculation. Ensure that you are using diagrams and pictures.
3. Record your explanation of the process using Flipgrid
4. Peer assess your classmates work and comment on the clarity, accuracy and use of visuals.

Blended learning

Student group presentation of:
Lattice Enthalpy and Enthalpy of solution & hydration

Task:
1. Form a group of 2-3 students
2. Decide as a group which topic you want to investigate:
- Lattice enthalpy
- Enthalpy of solution & hydration
3. Research about your chosen topic (use the textbooks, internet, YouTube etc)
4. Create a Google slide which is shared with all your group members and your teacher
5. Add the following items in your presentation:
- Accurate factual information that explains the concepts of your topic
- Diagrams and images to support the explanation
- A video either pre-recorded by you and your members in the group or a video from YouTube etc
- A set task to check for understanding when you present it to your classmates
6. decide who in your group is presenting what part of the presentation

Google folder for student group presentations