ThermodynamicsCh10

ThermodynamicsCh10 - Thermodynamics First Law energy can...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Background image of page 1

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

View Full DocumentRight Arrow Icon
Thermodynamics First Law – energy can never be created nor destroyed. (from CH 9) • We want to be able to predict spontaneity: under given conditions, occurs without outside intervention • Different than fast or slow!
Background image of page 2
Enthalpy to Predict Spontaneity? • C (s) + O 2 (g) CO 2 (g) H o = -393.5 kJ • This process is exothermic and spontaneous . •M o s t exothermic processes are spontaneous . •H 2 O (s) H 2 O (l) H o = 6.01 kJ • This process is endothermic and spontaneous . • Dissolving most ionic compounds in water is endothermic and spontaneous . • However, many (most?) endothermic processes are not spontaneous . • Enthalpy alone will not predict spontaneity.
Background image of page 3

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

View Full DocumentRight Arrow Icon
Spontaneous Non-spontaneous H = 0
Background image of page 4
Entropy Entropy S – How energy is distributed among energy levels of particles in universe • disorder of a system • Consider placing cards in order • If you have 2 cards, there is a 1 in 2 chance they will be in order. (2!) • If you have 13 cards (1 suit), there is a 1 in 6 x 10 9 chance they will be in order. (13!) • If you have 52 cards, there is a 1 in 8 x 10 67 chance they will be in order. (52!)
Background image of page 5

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

View Full DocumentRight Arrow Icon
Probability and Microstates More than disorder: Which would require more energy starting with a empty room: to put everything in order or to make it look exactly like this? Room of unnamed S117 student
Background image of page 6
Probability and Microstates • Positional Probability – Gas expansion – Phase change – solubility
Background image of page 7

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

View Full DocumentRight Arrow Icon
Entropy and Positional Probability Δ S = S f –S i S gas >> S liquid > S solid S increases when a solute (solid or liquid) is dissolved. S decreases when a solute (gas) is dissolved.
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/17/2012 for the course S 117 taught by Professor Stephenjacobson during the Fall '11 term at Indiana.

Page1 / 37

ThermodynamicsCh10 - Thermodynamics First Law energy can...

This preview shows document pages 1 - 9. Sign up to view the full document.

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