{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CH%20302%20(post)%20chapter%209a%20equilibrium%20Atkins%20and%20Jones

CH%20302%20(post)%20chapter%209a%20equilibrium%20Atkins%20and%20Jones

Info icon This preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
1 CHAPTER 6a Chemical Equilibrium 2 Basic Concepts Reversible reactions do not go to completion. z They can occur in either direction z Symbolically, this is represented as: The reactions proceed until the composition of the reaction mixture reaches a state of minimum free energy. ( ) ( ) ( ) ( ) g g g g D d + C c B b + A a 3 Basic Concepts Chemical equilibrium exists when two opposing reactions occur simultaneously at the same rate. z It is a stage in a chemical reaction when there is no further tendency for the concentrations or the partial pressures of a reaction mixture composition to change.
Image of page 1

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

View Full Document Right Arrow Icon
4 Basic Concepts Chemical equilibria are dynamic equilibria. z Molecules are continually reacting, even though the overall composition of the reaction mixture does not change. z The criteria that identify chemical equilibrium are: 1. The forward reaction and its reverse reaction are both taking place. 2. The forward and reverse reactions are occurring at equal rates – there is no net change. 5 Nitrogen dioxide shown immediately after expanding 2NO 2(g) Æ N 2 O 4(g) NO 2 colorless The color of the reaction mixture never become colorless. The reaction has established equilibrium. 6 Basic Concepts Any chemical reaction will establish equilibrium if it is carried out in a closed container. z If the reaction appears to have gone to completion, the equilibrium lies to the right . z This reaction is product favored. ( ) ( ) forward reverse left right reactants products → ←
Image of page 2
7 Basic Concepts An example of a reaction that is product favored is the following. Under the proper conditions, hydrogen gas and oxygen gas react to form water vapor. After equilibrium is established, the amount of reactants remaining are negligible. z This reaction lies far to the right . z The reaction essentially proceeds to completion. 2 2 2 ( ) ( ) 2 2 forward g g reverse H O H O → + ← 8 Basic Concepts z If the reaction appears to occur only to a slight extent, the reaction lies to the left . z This reaction is reactant favored. ( ) ( ) forward reverse left right reactants products → ← 9 Basic Concepts An example of a reaction that is reactant favored is the following. In a closed container at 25.0 o C, the decomposition of calcium oxide to calcium and oxygen gas occurs. After equilibrium is established, the amount of products are negligible. z This reaction lies far to the left . z The reaction essentially does not occur. ( ) ( ) 2( ) 2 2 forward s s g reverse CaO Ca O → + + ←
Image of page 3

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

View Full Document Right Arrow Icon
10 Characteristics of Chemical Equilibrium An example of chemical equilibrium is the reaction between water vapor and carbon monoxide in a closed container at a high temperature. If equal moles of water vapor and carbon monoxide are placed in the closed container, the initial concentration of reactants begins to decrease.
Image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern