CHEM1011 Lecture Notes - Lecture 26: Butene, Equilibrium Constant, Reaction Quotient

What is the value of Kc if a system at equilibrium is found to contain 0.30 M H2, 0.20M Br2, and 0.50 M HBr. The reaction occurring is: H2 + Br2 2 HBr Consider the isomerization reaction of 2 -butene given below for which Kc = 4.3 at 600 degree C. How much of the trans-isomer would be formed from 2.0 mol/L of cis-isomer heated at 600 degree C? Allow 4.0 mol HI in a 5.0 liter flask to reach equilibrium according to the reaction below. Find the concentrations of all components at equilibrium. Given: K = 2.04 cis-2-butene trans-2-butene x 10-2. 2HI (g) H2 (g) + I2 (g)

would the equilibrium constant for reaction be the written as C +→ A + B? 4. The equilibrium constant for the isomerization of cis-2-butene to trans-2-butene is K-2.07 at 400K. Calculate the standard reaction Gibbs energy (AG n) for the isomerization reaction. (Remember: (AGrn AG n+ RT In K) 5. At 525K, a 20.82 g sample of PCls is placed in a 5.00 L container. At equilibrium, 10.3 g PCl3 have formed. What is the value of K for the reaction? PCIs(g) PCl3(g) + Cl2(g) ←→ 6. Suppose a quantity of HI(g) was sealed in a 2.00 L container and brought to equilibrium at 698K. If K-54.3 for the reaction below, and [H11-0.0353M at equilibrium, a) determine the equilibrium concentration values for [H2] and [I2]. b) Also, what is the initial value of [HI]? H2(g) + 12(g) 2H1(g) 艹

ENT ives To determine equilibrium concentrations for species in solution . Examine temperature effects on reaction equilibrium Investigate the shift in equilibrium from different stresses on a system kills . Use colorimeter to determine unknown solution concentrations ced .Preparing temperature baths to change reaction conditions tionEquilibrium is defined as a state in which the concentrations of both the reactants and products have no tendency to change with time. We can restate this by saying that the rate of the forward reaction is equal to the rate of the reverse reaction. Recall that with rate we are simply defining how fast a reaction is proceeding, a speed at which the reaction proceeds. Take note that when writing an equilibrium expression, pure liquids (denoted by l or 2) and pure solids (denoted by s) are omitted. Typically we express the equilibrium by K or Kp where c and p denote either concentration or partial pressure respectively. We refer to this value of K, or Kp as an equilibrium constant For any reaction, Kc can be written as the product of the concentration of products, raised to their stoichiometric coefficients, divided by the product of the concentration of the reactants raised to their stoichiometric coefficients. See Equation (5-1) below for an example: aA(aq) + bB(aq-cC(aq) + dD(aq) (5-1) A] [B]b As mentioned before, K, or K, are equilibrium constants meaning that they will have the same value unless temperature is changed. This brings in two important ideas 1) We can perturb the equilibrium concentrations of a reaction, say [A] for instance which will cause the other concentrations to shift so that K for the reaction remains constant. 2) If we change temperature, we will either increase or decrease our value of K depending on the specific reaction we are examining. Determining K, and Equilibrium Concentrations During lecture we often discuss the idea of using ICE tables as a method for organizing and calculating concentrations of reactions as they proceed towards equilibrium. In a typical ICE table you need to know initial concentrations and the magnitude of K to determine the equilibrium concentrations. Alternatively, if you know the equilibrium concentrations for a reaction you can calculate K. For this experiment we will be examining a complex ion formation, when iron(III) ion