Kimia

TERMOKIMIA

This time I wanted to post a little about chemistry subjects that I had learned at schoolLEARN thermochemicalThermochemicalDo you have difficulty in learning Thermochemistry chapter? If you answer "Yes" then I think you are obliged to read the continuation of this article. What about you who are working on the problems lancer Thermochemistry? I think just continue reading this article, just maybe you can add a reference, right tul he he he hehe.In my experience, there are four main kinds of formulas that can be used to solve problems thermochemical, namely:1. Formula CalorimeterQ = m. c.ΔT = C. . ΔTThis formula is often used when we want to find the heat energy generated by mixing two solutions or to locate thermal energy involved in the reaction performed withusing Calorimeter. Examples of such questions as NaOH solution is mixed with a solution of H2SO4 and then we were told to look for heat neutralization, or a substance is burned in Calorimeter then the heat generated is transferred to the water in Calorimeter and we were told to look for heat burning substance.Oh yeah if known specific heat (c) substances then use the formula Q = mc? T but if the known heat capacity (C), then use the formula Q = C? T2. The formation enthalpy formulaΔH = ΔH products - ΔH reactantsThis formula is used when we are told to look for in terms of the enthalpy of a reaction and is known enthalpy of formation data of each species in the reaction. Examples of the type of problem with the completion of this formula is as follows:"Calculate the enthalpy of the reaction A + B -> C + D if known enthalpy of formation of A = .... KJ / mol, B = ... KJ / mol, C = ... KJ / mol and D = ... KJ / mol"3. Formula Energy AssociationTermination ΔH = ΔH - ΔH formationThis formula is used to solve the problems known to bond breaking energy data / data bond formation. An example of this problem is as follows:"Calculate the reaction CH4 + O2 -> CO2 + H2O if known CH bond energy data = ... KJ, O = O = ... KJ, KJ HO = ... and so on."4. Formula seeking reaction enthalpy legal basis HessProblems like these mark the completion of the data is that there is a reaction, and finally we were told to look for a specific reaction enthalpy. His way is to reorganize existing reactions so that if these reactions are summed amaka we will get a reaction in question. Example because is has the following characteristic:"Calculate the enthalpy of the reaction A + E -> B + F if known;A + D -> C + B ΔH = ... KJ / molB + D -> M ΔH = ... KJ / molE + F -> C + D ΔH = ... KJ / mol "Well to keep in mind here is that the enthalpy data is written in the book is in units of KJ / mol, for example, the enthalpy of formation of CO2 is ΔH = -394 KJ / mol, this means the formation of 1 mole of CO2 would release as much energy as KJ 394. If in question being asked as 0.5 mol, 2 mol, or 3 moles then of course you have to convert it first large enthalpy.