How Do Molecules Store Energy?

Introduction

Question: How do molecules store energy?
Common misconceptions: Energy is stored in bonds.
Observations: Some molecules have more energy (e.g., petrol, carbohydrates) than others (e.g., water, chalk).
Methods of discovery: Trial and error with food, fire-making, thermodynamics.

Device: Calorimeter (measures energy in fuels and foods).
- Example: Calories in food packets.

Energy and Bonds
- Derek Müller (Veritasium): Atoms lose energy by forming bonds, thus energy isn't in bonds.
- Nick Lucid (Science Asylum): Energy is stored in the molecule as a whole.

What is Energy?
- Focus on valence electrons (outside layer electrons controlling bonding).
- Separation of electrons from nuclei = potential energy.
Quantum Mechanics
- Electrons can only occupy certain volumes (orbitals).
- Orbital theory explains why electrons don't just stick to nuclei.
Chemical Bonds
- Bonds are pairs of electrons pulling nuclei together in a certain geometry.
- Two primary theories:
  - Valence Bond Theory: Easy to visualize, basis for school learning.
  - Molecular Orbital Theory: More complex, accurate for calculations.

Atomic Force Spectroscopy
- Real bonds seen in high electron density areas.
Energy Differences in Molecules
- Example: Beta glucose vs. alpha glucose (small orientation change = energy difference).

Misconceptions
- Chemists are not suggesting bonds are bags of energy.
Formation of Molecules
- Making molecules from atoms results in a loss of potential energy.
- Different bonds = different energy losses.
- Example: Glucose and dioxygen vs. carbon dioxide and water.

Energy Storage in Bonds
- Glucose and dioxygen store energy due to bond arrangements.
- Energy from breaking and forming bonds (activation energy required).