EJC 2023 Chemical Eqm Lecture Notes_Teacher Copy

2023 JC1 H2 CHEMISTRY (9729) CORE IDEA 3 - TRANSFORMATION Topic 7: CHEMICAL EQUILIBRIA Name: ___________________________________________ Civics Group: _________ Learning Outcomes Students should be able to: (a) explain, in terms of rates of the forward and reverse reactions , what is meant by a reversible reaction and dynamic equilibrium (b) state Le Chatelier’s Principle and apply it to deduce qualitatively (from appropriate information) the effects of changes in concentration, pressure or temperature, on a system at equilibrium (c) deduce whether changes in concentration, pressure or temperature or the presence of a catalyst affect the value of the equilibrium constant for a reaction (d) deduce expressions for equilibri um constants in terms of concentrations , Kc, and partial pressures, Kp [treatment of the relationship between Kp and Kc is not required] (e) calculate the values of equilibrium constants in terms of concentrations or partial pressures from appropriate data (f) calculate the quantities present at equilibrium, given appropriate data (such calculations will not require the solving of quadratic equations) (g) show understanding that the position of equilibrium is dependent on the standard Gibbs free energy change of reaction, G. [Quantitative treatment is not required] (h) describe and explain the conditions used in the Haber process, as an example of the importance of an understanding of chemical equilibrium in the chemical industry Recommended References: 1. Chemistry (for CIE AS & A Level) by Peter Cann & Peter Hughes 540 CAN 2. A-Level Chemistry by E.N. Ramsden 540 RAM Suggested Videos: (via URLs and QR codes provided or search using the titles) 1. What is Dynamic Equilibrium? The Chemistry Journey (Introductory video for chapter) 3. NO2 and N2O4 Equilibrium (Effect of Temperature) URL: https://youtu.be/wlD_ImYQAgQ URL: http://www.youtube.com/watch?v=tlGrBcgANSY 2. What is chemical equilibrium? George Zaidan and Charles Morton (Introductory video for chapter) 4. Chemistry: Demo: Shifting Equilibrium of [Fe(SCN)]2+ (Effect of Concentration) URL: https://youtu.be/dUMmoPdwBy4 URL: https://www.youtube.com/watch?v=ZOYyCTvLa9E TEACHER’S COPY

E u n o i a J u n i o r C o l l e g e 2 | P a g e Table of Contents Homogeneous vs. Heterogeneous Equilibrium ................................ ...................... 7 Calculation of Kc from Concentrations ................................ ................................ ... 9 Calculation of Concentrations from Kc ................................ ................................ . 10 Calculation of Kp from Partial Pressures ................................ .............................. 13 Calculation of Partial Pressures from Kp ................................ .............................. 14 G

3 G i b b s F r e e E n e r g y a n d E q u i l i b r i u m C o n s t a n t E u n o i a J u n i o r C o