Question

The reaction below was carried out in a calorimeter initially at 22.0 C. After 0.0180 g of iron reacted with 0.0100 g oxygen, the final temperature of the calorimeter was 30.6C. If the heat capacity of the entire calorimeter and solution was 12.0 J/C, what is the H of the reaction in units of kJ? (note the units on the calorimeter do not include mass)4Fe + 3O2 = 2Fe2O3

Answer 1

1280.71 kJ/mol

Step-by-step explanation:

First we need to determine the limit reagent in order to how many initial compound reacted and later and much heat that reacted quantity produced:

`0.0180 g Fe*(1 mole Fe)/(55.845 g Fe) *(1)/(4 moles Reacting Fe) =0.00008058`

`0.0100 g O2*(1 mole O2)/(31.98 g O2) *(1)/(3 moles Reacting O2) =0.00010423`

The limit reagent is Iron.

Now to determine how much heat was generated by the reaction of those 0.0180 g Fe we take into account that the calorimeter is adiabatic and the heat produced by the reaction is the heat absorbed by the calorimeter and the solution:

`Q(Calorimeter and solution)=-Q(Rxn)`

C*ΔT=-ΔH(rxn)*n

Where C is the Heat Capacity of the entire calorimeter and the solution and n is the number of moles reacting:

Then we solve for n:

`H=(C * T)/(n) =(12.0 J/C*8.6 C)/(0.00008058 mol Fe) = 1280.71 kJ/mol`