6 Outline - Chapter 6 Chemistry Outline Lecture...

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

View Full Document Right Arrow Icon
Chapter 6 Chemistry Outline Lecture Thermodynamicss- the study of heat and its transformations to other forms of nrg Thermochemistry- the study of the charge in heat associated with chemical and physical changes. System- what you are studying Surroundings- everything else Universe = system + surroundings Internal nrg (E) of the system is the sum of the potential nrg and the kinetic nrg of all the particles in the system E = E(final) – E(initial) = E(products) – E(reactants) if nrg is gained final > initial and E > 0 (positive) if nrg is lost final <initial and E < 0 (negative) E of the system nrg gained came from surroundings nrg lost it went to the surroundings whatever happens to the sys, the opp happens to the surr E(sys) = - E (surr) First law of thermodynamics is nrg is neither lost or gained; can only be moved or converted. E (universe) = 0 Nrg is transferred in two ways Heat (q)- temperature Work (w)- moved by force E= q + w heat added = +q; heat released – q. Work done on sys = + w; work done by sys = -w in chem rxns, work is typically done by expanding or compressing gas. PV work. At constant pressure, an inc in V is work done by the sys -w w= -P V where V = V(final) – V(initial) Fixed volume, w = 0 E = q ( t)
Background image of page 1

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

View Full DocumentRight Arrow Icon
Units of nrg- nrg SI= Joule (J) Work = force x distance = mass x acceleration x distance = kg x m/s^2 x m = J calorie (cal) = nrg needed to raise 1 g of water 1 C Nutri Cal = 1 kcal State Function- no path, only initial and final conditions Internal nrg (E) is a st f(x) only worry about starting and ending nrg (other st f(x) P and V (both depend on initial and final conditions Open to atmosphere = constant P Enthalpy (H) thermodynamic quality for rxns at constant P H = E + P V But E = q - P V H= q(p) [heat at constant P] H is heat gained or lost at constant P. W/ H PV work can ignored H is st f(x) ∴∆ H = H(final) – H(initial) = H(products) > H(reactants) H positive endothermic , sys absorbs H(reactants) > H(products) H is negative exothermic, sys release Endo ex. Breaking bonds, boiling water, heat + reactants > products Exo ex. Forming bonds, condensing vapor, heat is product Calorimetry- the study of s in nrg. Heat gained/lost by sys is determined by T in surr Heat Capacity- the quantity of heat needed to raise the T of an object 1K
Background image of page 2
HC = q/ T in J/K (value is explicit to the object of fixed mass)
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 / 8

6 Outline - Chapter 6 Chemistry Outline Lecture...

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