3 different methods

[Megan Bundy 2K]

in terms of exam questions, will we be given a situation and be able to choose which method to use, or will we be required to figure it out in one specific method?

[AudreyQian1J]

Hello,
Using which method would depend on the information that is given in the question. For example, if a table of values of bond enthalpies are given in the equation, then we use bond enthalpies to calculate enthalpy reaction (method 2 in lecture). If we are given a table of standard enthalpies of formation, we would use sum of enthalpies of formation of products minus the sum of enthalpies of formation of reactants (method 3 in lecture). And if a series of reactions is given, we would use Hess's Law.

[Jack Amos 2I]

Hello,
Using which method would depend on the information that is given in the question. For example, if a table of values of bond enthalpies are given in the equation, then we use bond enthalpies to calculate enthalpy reaction (method 2 in lecture). If we are given a table of standard enthalpies of formation, we would use sum of enthalpies of formation of products minus the sum of enthalpies of formation of reactants (method 3 in lecture). And if a series of reactions is given, we would use Hess's Law.

So we will be given values of bond enthalpies or standard enthalpies, we won't have to memorize them? I missed it if Dr. Lavelle did mention that.

[Aanjaneyaa]

It really does depend on the situation. Often times, the question will state whether they want you to use one method over another.

[Hannah Thornton 1F]

You would choose which method to use depending on the situation, or if the question tells you which to use. If reactions are given, you would use Hess's Law. If the question gives you the bond enthalpy values, then you would use the bond enthalpy method. If the standard enthalpies of formation is given, then you would use that method.

[Eric Sun 2G]

I think that we will be expected to know how to use all 3 methods as each problem could provide different information that we would have to use to solve for the enthalpy of the reaction.

[AudreyQian1J]

So we will be given values of bond enthalpies or standard enthalpies, we won't have to memorize them? I missed it if Dr. Lavelle did mention that.

I don't think we need to memorize them. They will be given in the problem.

[Isabelle Kim 3E]

I'm pretty sure that it would be quite straightforward given the information in the problem in order to select which method must be used to calculate for the enthalpy change. For example, it would make sense to use bond enthalpy method when given the mean bond enthalpies of the presented molecules in the problem.

[005493723]

I think we will be able to tell by the given information of the problem. Since Lavelle usually gives enough information and doesn't expect memorization of many values, you can usually deduct what method can be used with the info