Expert in study
alarm
Ask
Other

Given the reaction SO3 ---> SO2 + 1/2 O2 (triangle H degrees= 98.9 kJ , triangle S degrees = 93.9 J/ mol K): A) is the reaction spontaneous at 25... |

Register to add an answer
answers: 1
390 cents
Answer:

In order to find out if a reaction is spontaneous we need to find the Gibbs free energy value using the equation below:

deltaG=deltaH-TdeltaS

where deltaG is the Gibbs free energy change, deltaH is the enthalpy change, T is the temperature in Kelvin, and deltaS is the entropy change.  If the delta G value is negative, then the reaction is spontaneous.  Remember that all of the units must match up (25 C is 298 K).

deltaG=98.9 kJ-(298 K)(0.0939 kJ/K)=70.92 kJ

Since the deltaG value is positive the reaction is not spontaneous.

The reaction will reverse direction when the deltaG value is equal to 0.  This is when the reaction is at equlibrium and the forward and reverse reactions are both happening.  We can use the same equation to solve for T:

0=deltaH-TdeltaS

TdeltaS=deltaH

T=deltaH/deltaS=98.9 kJ/0.0939 kJ/K=1053 K=780 C.

The temperature where the reaction begins to reverse itself is 780 C.

275
For answers need to register.
Contacts
mail@expertinstudy.com
Feedback
Expert in study
About us
For new users
For new experts
Terms and Conditions