Chapter10_Fall11

Chapter10_Fall11 - 10 10.1 10.2 10.3 10.4 10.5 10.6 10.7...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Thermochemistry 10 10.1 Energy and Energy Changes 10.2 Introduction to Thermodynamics 10.3 Enthalpy 10.4 Calorimetry 10.5 Hess’s Law 10.6 Standard Enthalpies of Formation 10.7 Bond Enthalpy and the Stability of Covalent Molecules 10.8 Lattice Energy and the Stability of Ionic Compounds Energy and Energy Changes Energy is the capacity to do work or transfer heat. Types of Energy Kinetic (E k ) – energy resulting from motion ࢓࢛ Thermal energy is a form of kinetic energy, it arises from motion of atoms and molecules. Potential - energy possessed by an object by virtue of its position. Chemical energy is energy stored within the structural units of chemical substances. Electrostatic energy is potential energy that results from the interaction of charged particles. ࢋ࢒ ૚૛ Chemical reactions can produce energy
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The system is a part of the universe that is of specific interest. The surroundings constitute the rest of the universe outside the system. Surroundings Universe = System + Surroundings Definitions System Energy and Energy Changes Thermochemistry is the study of heat (the transfer of thermal energy) in chemical reactions. Heat is the transfer of thermal energy. Heat is either absorbed or released during a process. Energy and Energy Changes An exothermic process occurs when heat is transferred from the system to the surroundings. “Feels hot!” heat System 4Fe(s) + 3O 2 (g) -> 2Fe 2 O 3 (s) Energy and Energy Changes An endothermic process occurs when heat is transferred the surroundings the system. “Feels cold” heat NH 4 NO 3 + H 2 O NH 3 + NO 3 + H 3 O +
Background image of page 2
Introduction to Thermodynamics Thermodynamics is the study of the interconversion of heat and other kinds of energy. In thermodynamics, there are three types of systems: An open system can exchange mass and energy with the surroundings. A closed system allows the transfer of energy but not mass. An isolated system does not exchange either mass or energy with its surroundings. Introduction to Thermodynamics State functions are properties that are determined by the state of the system, regardless of how that condition was achieved. The magnitude of change depends only on the initial and final states of the system. Internal Energy Enthalpy Entropy Free Energy Pressure Volume Temperature The First Law of Thermodynamics The first law of thermodynamics states that energy can be converted from one form to another, but cannot be created or destroyed. Δ U is the change in the internal energy. “sys” and “surr” denote system and surroundings, respectively. Δ U = U f U i ; the difference in the energies of the initial and final states. Δ U sys + Δ U surr = 0 Δ U sys = – Δ U surr Work and Heat The overall change in the system’s internal energy is given by: q is heat is positive for an endothermic process (heat absorbed by the system) is negative for an exothermic process (heat released by the system) w is work w is positive for work done on
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 12

Chapter10_Fall11 - 10 10.1 10.2 10.3 10.4 10.5 10.6 10.7...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online