00:01
Hello students for the first part of this equation the standard molar enthalpy for formation of methane is equal to minus 74 .8 kilojoule per mole for chlorine gas the enthalpy of formation would be zero as it is its most stable form the enthalpy of formation for hydrochlority of formation for hydrochlority asset is minus 92 .3 kilojoules per mole.
00:44
The standard enthalpy of this reaction is given to us as minus 305 kilojoules.
00:54
Now the enthalpy change of a reaction is equal to the standard formation in enthalpys for products minus the standard formation in enthalpys for products minus the standard formation enthalpy for reactants.
01:20
Now substituting the values for the enthalpy that is 305 kilojoules is equal to the standard formation enthalpy for the product, chloroform and three moles of hcl.
01:44
For hcl the value is minus 92 .3 kilojoules minus the standard enthalpy for reactant which is methane its value is minus 74 .8 kilojoules.
02:03
After doing the required calculations the molar enthalpy of formation of the chloroform comes out to be minus 102 .9 kilojoules hence this is the value of molar enthalpy.
02:29
In the next part the the enthalpy of the reaction would be equal to the enthalpy of formation of products minus enthalpy of formation of reactants, which is equal to for the products, the enthalpyof formation of magnesium nitrate plus twice the enthalpy of formation of agcl, that is silver chloride, because of its 2 moles minus the enthalpy of reactants...