Thermochemistry-Hess's Law

Hey =) Im gonna do my best to help you and this is what I came up with.... I found out how to get the formula of Mg + 1/2 O2 ---> MgO... The only thing is that I didnt attend the (delta) H for the target formula. I believe you can happen upon it using the appendix of your book ( assuming they want you to stupefy the monetary standard Enthalpies of Formation for the other formulas ).... For my rference to them in this answer, I substituted the value with variables.... To find Mg + 1/2 O2 --> MgO, (1) Mg + 2HCl --> H2 + MgCl2 (delta) H = X (2) MgO + 2HCl --> H2O + MgCl2 (delta) H = Y (3) H2 + 1/2 O2 --> H2O (delta) H = -285.8 KJ You know you already need the Mg and the 1/2 O2 on the left situation and the MgO on the right side of the equasion.... I saw quickly that the Mg and 1/2 O2 are already on the left but the MgO in equasion (2) was on the left. Therefore, I switched it around. I ended with (1) Mg + 2HCl --> H2 + MgCl2 (delta) H = X (2) H2O + MgCl2 --> MgO + 2HCl (delta) H = -Y (3) H2 + 1/2 O2 --> H2O (delta) H = -285.

8 KJ Basically, only the second equasion changed and the Y is now negative feature u switched the products and reactants.... I tried working it here and combination them. Everything proceeded to cancel out except for the Mg, 1/2O2 and MgO =) Hope you soundless all that! OH and Im sure you know how to find the Standard Enthalpy of Formation for an equasion... But in case you befoolt its .... [Sum Products] - [ Sum Reactants] -- Like I said, all enthalpies should be in the back of the book. Be sure youre careful to mind the sound out of the chemical. Certain substances like Water exist as a liquid and a gas at room temperature. Therefore, assoil sure you look at the GAS Enthalpy for gas and the LIQUID enthalpy for liquid If you want to get a full essay, order it on our website: Ordercustompaper.com

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