chm2045ch6 - Chapter 6 Principles of Reactivity: Energy and...

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

View Full Document Right Arrow Icon
Chapter 6 Principles of Reactivity: Energy and Chemical Reactions Thermochemistry
Background image of page 1

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

View Full DocumentRight Arrow Icon
Goals of Chapter Heat transfer associated with changes in temperature and changes of state. The First Law of Thermodynamics. Define and understand the state functions enthalpy (H) and internal energy (E). Calculate the energy changes in chemical reactions and learn how these changes are measured.
Background image of page 2
Thermochemistry Study of the relationships between energy changes and chemical processes
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 The capacity to do work or to transfer heat Kinetic Energy energy of motion; KE = ½ mv 2 Potential Energy stored energy : fuel of motor-cars, trains, jets. It is converted into heat and then to work. due to relative position : water at the top of a water wheel. It is converted to mechanical E electrostatic : lightning converts it to light and heat
Background image of page 4
Joule SI unit for energy the energy of a 2 kg mass moving at 1 m/s KE = ½ mv 2 = ½(2 kg)(1 m/s) 2 = 1 kg × m 2 /s 2 = 1 J 1 cal is the amount of energy required to raise the temperature of 1 g water 1°C 1 cal = 4.184 J 1 cal = 1 calorie 1 Cal = 1000 cal = 1 kcal 1 Cal = dietary Calorie (nutritional calorie)
Background image of page 5

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

View Full DocumentRight Arrow Icon
System the part of the universe under study the substances involved in the chemical and physical changes under investigation in a chemistry lab, the system may be the chemicals inside a beaker
Background image of page 6
Surroundings the rest of the universe in chemistry lab, the surroundings are outside the beaker (chemicals are in the beaker) The system plus the surroundings is the universe.
Background image of page 7

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

View Full DocumentRight Arrow Icon
System and Surroundings SYSTEM The object under study SURROUNDINGS Everything outside the system
Background image of page 8
Thermodynamic State The set of conditions that specify all of the properties of the system is called the thermodynamic state of a system . For example the thermodynamic state could include: The number of moles and identity of each substance. The physical states of each substance. The temperature of the system. The pressure of the system. The volume of the system. The height of a body relative to the ground.
Background image of page 9

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

View Full DocumentRight Arrow Icon
First Law of Thermodynamics -law of conservation of energy; during any process, energy is neither created nor destroyed, it is merely converted from one form to another * the mass of a substance is a form of energy E = mc 2 (Albert Einstein) e.g. in nuclear reactions mass is not conserved, it is transformed into heat (E) * “The combined amount of energy in the universe is constant.”
Background image of page 10
Internal Energy (E) the total energy of a system: Σ of kinetic and potential E of all atoms, molecules, or ions in the system E cannot be measured exactly E is a state function; change in E does not depend on how change of state happens E: change in E. E can be measured E = E final – E initial (final and initial states) E > 0 (+) indicates system gains energy during process (E increases, ) E < 0 (−) indicates system loses energy during process (E decreases, )
Background image of page 11

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

View Full DocumentRight Arrow Icon
E = q + w statement of first law of thermodynamics
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.

This note was uploaded on 08/24/2008 for the course CHM 2045 taught by Professor Geiger during the Summer '08 term at University of Central Florida.

Page1 / 57

chm2045ch6 - Chapter 6 Principles of Reactivity: Energy and...

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