Calculate the enthalpy change when 4.00 mol cl2o7 is produced according to the following balanced equation: 2cl2(g) + 7o2(g) + 130kcal -> 2cl2o7(g) a. 1040 kcal b. -260 kcal c. 260 kcal d. -1040 kcal ** if you could explain it as well, that would be much appreciated if not, thats okay too its multiple choice

So the equation is,

2Cl2(g) + 7O2(g) + 130kcal -> 2Cl2O7(g)

from this , ΔH°rxn=

is mentioned because it is for per mole of reaction. So for 4. moles of the product we need 4/2 moles of reaction to be used to calculate associated enthalphy change for the reaction.

Therefore

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.