bond enthalpies
Overview
Bond enthalpies represent the energy required to break one mole of a specific covalent bond in the gaseous state, providing a crucial tool for estimating enthalpy changes of reactions. This lesson explores the definition, types (mean vs. bond dissociation), and applications of bond enthalpies in calculating reaction energetics. Understanding bond enthalpies is fundamental for predicting whether a reaction is endothermic or exothermic.
Introduction to Bond Enthalpies
Bond enthalpy, often referred to as bond energy, is a fundamental concept in chemistry that quantifies the strength of a covalent bond. It is defined as the **energy required to break one mole of a specific type of covalent bond in the gaseous state**. This definition is crucial because bond breakin...
Unlock 4 More Sections
Sign up free to access the complete notes, key concepts, and exam tips for this topic.
No credit card required · Free forever
Key Concepts
- Bond Enthalpy (Bond Energy): The energy required to break one mole of a specific type of covalent bond in the gaseous state.
- Bond Breaking: An endothermic process, as energy must be supplied to overcome the attractive forces between atoms.
- Bond Making: An exothermic process, as energy is released when new, more stable bonds are formed.
- Mean Bond Enthalpy: An average value for the energy required to break a particular type of bond across a range of different molecules.
- +3 more (sign up to view)
Exam Tips
- →Always draw out the full displayed formula of all reactants and products to accurately count the number and type of bonds broken and formed. This prevents common counting errors.
- →Remember the formula: ΔHrxn = Σ (Bonds Broken) - Σ (Bonds Formed). A common mistake is to add the energy of formed bonds, leading to an incorrect sign for ΔH.
- +2 more tips (sign up)
More Chemistry Notes