Question

A chemical engineer is studying the following reaction: HCH,CO (0)+CH NH (aq) – CH, CO (q) + CH3NH (g) At the temperature the engineer picks, the equilibrium constant for this reaction is 2.2. The engineer charges ("fills") four reaction vessels with acetic acid and methylamine and lets the reaction begin. He then measures the composition of the mixture inside each vessel from time to time. His first set of measurements are shown in the table below. Predict the changes in the compositions the engineer should expect next time he measures the compositions compound concentration expected change in concentration HCH.CO 116 M of increase o decrease (no change) CH,NH, 106 M Tincrease o decrease (no change) 0.52 M increase o decrease (ne change) CH,CO CH, NH 0 50 M increase o decrease (no change) HCH.CO, 0.99 M of increase I decrease (no change) C| NHA 0.89 M increase o decrease (no change) CH,CO, 0.69 M Tincrease o decrease (no change) || NH 067M increase o decrease (ne change) HCH,CO, 094 M increase o decrease (no change) CHINH, 0.81 M o increase o decrease (no change) сн,со, 1.32 M increase I decrease (no change) CH,NH 129 M increase o decrease (no change)

Answer 1

reaction vessel A.

Q = [CH3CO2-][CH3NH3+] / [HCH3CO2][CH3NH2]

Q = (0.52)(0.50) / (1.16)(1.06)

Q = 0.212

Q < Kc , So equilibrium shifts in forward direction.

[CH3CO2-] = increase

[CH3NH3+] = increase

[HCH3CO2] = decraese

[CH3NH2] = decrease

reaction vessel B.

Q = [CH3CO2-][CH3NH3+] / [HCH3CO2][CH3NH2]

Q = (0.69)(0.67) / (0.99)(0.89)

Q = 0.52

Q < Kc , So equilibrium shifts in forward direction.

[CH3CO2-] = increase

[CH3NH3+] = increase

[HCH3CO2] = decraese

[CH3NH2] = decrease

reaction vessel C.

Q = [CH3CO2-][CH3NH3+] / [HCH3CO2][CH3NH2]

Q = (1.32)(1.29) / (0.94)(0.81)

Q = 2.2

Q =  Kc , So reaction is at equilibrium.

[CH3CO2-] = no change

[CH3NH3+] = no change

[HCH3CO2] = no change

[CH3NH2] = no change