Among the many complex ions of cobalt are Co(NH3)63+(aq) + 3 en(aq) ⇌ Co(en)33+(aq) + 6 NH3(aq) where "en" stands for ethylenediamine, H2NCH2CH2NH2. Six Co―N bonds are broken, and six Co―N bonds are formed in this reaction, so ΔH o rxn ≈ 0; yet K > 1. What are the signs of ΔS o and ΔG o ? ΔS o < 0 ΔS o = 0 ΔS o > 0 ΔG o < 0 ΔG o = 0 ΔG o > 0 What drives the reaction? Free energy is positive. Enthapy is ≈ 0. a decrease in entropy an increase in entropy

consider the reaction below.

 no rx

at 500 k, the reaction is at equilibrium with the following concentrations.

[pci5]= 0.0095 m

[pci3] = 0.020

[ci2] = 0.020 m

what is the equilibrium constant for the given reaction?

0.042

0.42

2.4

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definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.