05_lecture-akins031311 - Chemistry 10301, Spring 2011...

Info iconThis preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
1 5 Thermochemistry Chapter Chemistry 10301, Spring 2011 Instructor: Dr. Daniel L. Akins
Background image of page 1

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

View Full DocumentRight Arrow Icon
Thermochemistry 5 5.1 Energy and Energy Changes Forms of Energy Energy Changes in Chemical Reactions Units of Energy 5.2 Introduction to Thermodynamics States and State Functions The First Law of Thermodynamics Work and Heat 5.3 Enthalpy Reactions Carried Out at Constant Volume or at Constant Pressure Enthalpy and Enthalpy Changes Thermochemical Equations 5.4 Calorimetry Specific Heat and Heat Capacity Constant-Pressure Calorimetry Constant-Volume Calorimetry 5.5 Hess’s Law 5.6 Standard Enthalpies of Formation
Background image of page 2
Energy and Energy Changes Energy is the capacity to do work or transfer heat. All forms of energy are either kinetic or potential. Kinetic energy (E K ) is the energy of motion. m is the mass of the object in kilograms u is the velocity in meters per second. E K = mu 2 1 2 5.1
Background image of page 3

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

View Full DocumentRight Arrow Icon
Energy and Energy Changes Potential energy is the 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. Q 1 and Q 2 represent two charges separated by the distance, d . 12 el QQ E d
Background image of page 4
Energy and Energy Changes Kinetic and potential energy are interconvertible. The law of conservation of energy states that the total amount of energy in the universe is constant. When energy of one form disappears, the same amount of energy reappears in another form or forms.
Background image of page 5

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

View Full DocumentRight Arrow Icon
Energy and Energy Changes The system is a part of the universe that is of specific interest. The surroundings constitute the rest of the universe outside the system. The system is usually defined as the substances involved in chemical and physical changes. System Surroundings Universe = System + Surroundings
Background image of page 6
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. Surroundings heat
Background image of page 7

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

View Full DocumentRight Arrow Icon
Energy and Energy Changes An exothermic process occurs when heat is transferred from the system to the surroundings. “Feels hot!” Surroundings Universe = System + Surroundings heat System 2H 2 ( g ) + O 2 ( g ) 2H 2 O( l ) + energy
Background image of page 8
Energy and Energy Changes An endothermic process occurs when heat is transferred from the surroundings to the system. “Feels cold” energy + 2HgO( s ) 2Hg( l ) + O 2 ( g ) Surroundings Universe = System + Surroundings heat System
Background image of page 9

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

View Full DocumentRight Arrow Icon
Energy and Energy Changes
Background image of page 10
Energy and Energy Changes Calculate the energy in joules of a 5.25 g object moving at a speed of 655 m/s. Solution: Step 1: First convert grams to kilograms. (0.00525 kg) Step 2: Substitute into the equation for kinetic energy and solve. 2 1 = 2 K E mu 2 1 = (0.00525 kg)(655 m/s) = 1130 J 2 K E
Background image of page 11

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

View Full DocumentRight Arrow Icon
Introduction to Thermodynamics Thermodynamics is the study of the interconversion of heat and other kinds of energy.
Background image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 60

05_lecture-akins031311 - Chemistry 10301, Spring 2011...

This preview shows document pages 1 - 13. Sign up to view the full document.

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