14 Aug How can I calculate delta G of a reaction?
If the reaction is carried out under standard conditions (unit concentrations and pressures) and at a temperature that corresponds to a table of thermodynamic values (usually 298.15 K), then you can subtract the standard Gibbs Free Energy of Formation (##DeltaG_f##) of the reactants from those of the products.
Otherwise, you will need to take a more complicated approach:
Calculate the standard enthalpy of reaction by subtracting ##DeltaH_f## of the reactants from the products.
Follow a similar procedure to calculate the standard entropy of reaction (##DeltaS##).
Calculate ##DeltaG^0## for the reaction using the equation ##DeltaG^0=DeltaH^0-TDeltaS^0##. This makes the approximation that ##DeltaH^0## and ##DeltaS^0## are independent of temperature. The superscript 0 indicates “under standard conditions”.
The ##DeltaG^0## that you calculated in step 3 is the standard change in Gibbs Free Energy, assuming that all reactants and products are present in unit concentrations (1 M for solutes or 1 bar partial pressure for gases or pure liquids or pure solids). If you want to calculate ##DeltaG## under non-standard conditions, you need to use the equation
##DeltaG = DeltaG^0 + RTlnQ## where Q is the ratio of concentrations (or activities) of the products divided by the reactants. Under standard conditions Q=1 and ##DeltaG=DeltaG^0##. Under equilibrium conditions, Q=K and ##DeltaG=0## so ##DeltaG^0=-RTlnK##.
For higher accuracy, you can account for the temperature dependence of ##DeltaH^0## and ##DeltaS^0## by considering the ##DeltaT## between the actual temperature of reaction in the standard temperature of the thermodynamic table you’re using. For example, if your reaction is at 350K and your table is for 298K then for each reactant and product the enthalpy and entropy of formation is:
##Delta_fH_350## = ##Delta_fH_298 + C_P(350-298)##
##S_350## = ##S_298 + C_P ln(350/298)##
Then calculate the ##DeltaH## and ##DeltaS## for the reaction and the rest of the procedure is unchanged.
Our website has a team of professional writers who can help you write any of your homework. They will write your papers from scratch. We also have a team of editors just to make sure all papers are of HIGH QUALITY & PLAGIARISM FREE. To make an Order you only need to click Ask A Question and we will direct you to our Order Page at WriteDemy. Then fill Our Order Form with all your assignment instructions. Select your deadline and pay for your paper. You will get it few hours before your set deadline.
Fill in all the assignment paper details that are required in the order form with the standard information being the page count, deadline, academic level and type of paper. It is advisable to have this information at hand so that you can quickly fill in the necessary information needed in the form for the essay writer to be immediately assigned to your writing project. Make payment for the custom essay order to enable us to assign a suitable writer to your order. Payments are made through Paypal on a secured billing page. Finally, sit back and relax.
About Wridemy
We are a professional paper writing website. If you have searched a question and bumped into our website just know you are in the right place to get help in your coursework. We offer HIGH QUALITY & PLAGIARISM FREE Papers.
How It Works
To make an Order you only need to click on “Place Order” and we will direct you to our Order Page. Fill Our Order Form with all your assignment instructions. Select your deadline and pay for your paper. You will get it few hours before your set deadline.
Are there Discounts?
All new clients are eligible for 20% off in their first Order. Our payment method is safe and secure.