# Summary of session 5

- In a chemical reaction, the total mass of the reactants equals the total mass of the products.
- Balanced chemical equations are used to concisely represent chemical reactions.
- The structural formulas of organic molecules can be divided into the carbon-hydrogen framework or skeleton, and the functional group(s). In the first approximation, the functional groups are the sites where reaction occurs, the framework remaining unreactive.
- The above approximation works best when the framework consists of saturated carbon atoms.

OpenLearn - Discovering chemistry
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