hesslaw - Cut to the Chase: Hess Law Steps to follow when...

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Cut to the Chase: Hess’ Law Steps to follow when doing Hess Law problem: Step 1 Look at the overall reaction and select the first reactant. Find that reactant in one of the mechanism steps (one of the two or three step reactions given). If that reactant is unique to only one reaction (is not in any other reaction) then that reactant can be used. If it is not unique to only one reaction, then skip the first reactant and go to the second reactant. Step 2 Check to see if the selected reactant is on the left side of the mechanism reaction. If it is not, you must reverse the reaction. This will change the sign of the H, S, or G value given at the end of the reaction. Check to see if there is the correct number of molecules in the mechanism reaction so that it matches the number in the overall reaction. If not, the mechanism step must be divided or multiplied by a factor in order to make the molecule in the mechanism equal to the same number that are in the overall reaction. The value for H, G, or S at the end of the equation must be multiplied or divided by the same number. After making the necessary changes to the H, G, or S value, put that number in your calculator. You will not use this mechanism step again. Each step will only be used one time.
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hesslaw - Cut to the Chase: Hess Law Steps to follow when...

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