Question

The Kb for methylamine (CH3NH2) at 25 degrees C is 4.4 * 10-4 (a)Write the chemical equation for the equilibrium that corresponds to Kb. (b) By using the value of Kb, calculate for the equilibrium in part (a). (c) What is the value of at equilibrium? (d) What is the value of DELTA G when , [H+] = 6.7 * 10-9 M , [CH3NH3 + ]= 2.4 *10-3 M, and [CH3NH2] = 0.098 M?

Answer 1

The question involves the understanding of the concept of equilibrium in chemical reactions and how it applies to the weak base methylamine. The equilibrium equation has been written, and steps on how to find the equilibrium concentrations and DELTA G (free energy) have been elaborated.

Step-by-step explanation:

(a) The equilibrium for methylamine (CH3NH2) when it behaves as a weak base in water can be represented as: CH3NH2 + H2O = CH3NH3+ + OH-.

(b) Using the given equation Kb = [CH3NH3+][OH-]/[CH3NH2], and the provided value of Kb, we can get the equilibrium concentrations of the components involved. However, without any starting concentrations or degree of dissociation, we can't compute exact values.

(c) The value at equilibrium will be determined by the ratios of products to reactants concentrations raised to their respective coefficients as dictated by the balanced equation.

(d) For calculating DELTA G, the formula to use is ΔG = -RT lnK, where R is the gas constant and T is the temperature in Kelvin. We would need the equilibrium constant K for the reaction, which is not given in the question.

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