AP Notes, Outlines, Study Guides, Vocabulary, Practice Exams and more!

Properties of Equilibrium

equilibrium in reactions - when forward/reverse reactions occur at same rate  

  • ratio of partial pressures, concentrations equals constant
  • pressures no longer change
  • reaction continues to occur, but ratio stays the same (no net change)
  • can be reached from either direction

Haber Process - synthesizing ammonia from hydrogen/nitrogen 

  • world’s main source for fixed nitrogen
  • N2 + 3H2 <<>> 2NH3

equilibrium constant - only changed by temperature, not by reaction mechanism 

  • for reaction aA + bB <<>> cC + dD
  • Keq = (C concentration)c(D concentration)d / (A concentration)a(B concentration)b
  • value determined by coefficients in chemical equation
  • value greater than 1 >> equilibrium towards product side
  • value less than 1 >> equilibrium towards reactant side
  • for any reaction, constant equal to reciprocal of constant for reverse reaction
  • constant raised to power equal to number by which reaction is multiplied
  • constants multiplied together for net reactions involving 2+ steps
  • do not include pure solids, pure liquids, or solvents in finding constant

For the reaction CaCo3(s) >> CaO(s) + CO2(g), K = 0.0108. Find the equilibrium weight of CO2 if 2g of CaCo3, 2g of CaO, and 0.5g of CO2 were placed in a 1 liter flask.  

  • don't take account of solids in the reaction
  • K = [CO2] = 0.0108 mol
  • 0.0108 mol = grams CO2 / CO2 molar mass
  • 0.0108 = grams CO2 / (12 + 16 x 2)
  • grams CO2 = 0.0108 (44)
  • 0.475 g

At equilibrium for the reaction 2NO(g) + Cl2(g) >> 2NOCl, K = 51. If [NOCl] = 0.10 and [Cl2] = 0.20, find [NO]  

  • K = 51 = [NOCl]2 / ([NO]2[Cl2])
  • [NO]2 = 0.12 / 0.2 / 51 = 0.00098
  • [NO] = 0.031
Subject: 
Subject X2: 

Need Help?

We hope your visit has been a productive one. If you're having any problems, or would like to give some feedback, we'd love to hear from you.

For general help, questions, and suggestions, try our dedicated support forums.

If you need to contact the Course-Notes.Org web experience team, please use our contact form.

Need Notes?

While we strive to provide the most comprehensive notes for as many high school textbooks as possible, there are certainly going to be some that we miss. Drop us a note and let us know which textbooks you need. Be sure to include which edition of the textbook you are using! If we see enough demand, we'll do whatever we can to get those notes up on the site for you!