# Chemistry

posted by .

4Fe + 3O2 -> 2Fe2O3 + 1.65E3 kJ

C) what is the enthalpy change for the formation of 23.6 g of iron(iii) oxide?

I'm trying to understand thermochemical reactions and stoichiometry, so could you please tell me if this is correct? And please explain the parts that I clearly don't understand:

The question, is it the same thing as asking, "how much energy was released if iron(iii) oxide had a mass of 23.6 g?"
According to the equation:
4 moles of Fe and 3 moles of O2 react to release -1.65E3 kJ. ....then 2 moles of Fe "contains" -1.65E3 kJ??

To calculate how much kJ of energy was released when the mass of Fe2O3 was 23.6g, we need the amount of moles:
23.6 g are in 1 mole of Fe2O3, and every mole of Fe2O3 is 160g, the molar mass. (??) which, I think??, explains why this works :
23.6g Fe2O3 x 1 mol Fe2O3/160g
And Since there's -1.65E3 kJ per 2 moles of Fe2O3: -1.65E3/2 mol Fe2O3

Putting it altogether:
Enthalpy = 23.6 g Fe2O3 x 1 mol Fe2O3/160g x -1.65E3kJ/2 mol 2Fe2O3
= 1.22E2 kJ

I'm hoping I've got the units all right too...

Also, what does it mean if "there's -1.65E3 kJ per 2 moles of Fe2O3"? Then there's -1.65E3 kJ 'contained' in the Fe2O3??? Because we wouldn't say -1.65E3 kJ is RELEASED when Fe2O3 reacts, because Fe2O3 is the product... So what exactly is going on (between Fe2O3 and the energy or enthalpy change or whatever.......)??

## Similar Questions

1. ### chemistry

when iron rusts in air, iron(III) oxide is produced. how many moles react with 2.4 iron in the rusting reaction?
2. ### science

iron (III) oxide is formed when iron combines with oxygen in the air. how many grams of Fe2O3 are formed when 16.7g of Fe reacts completely with oxygen?
3. ### Chemistry

Deterioration of buildings, bridges, and other structures through the rusting of iron costs millions of dollars everyday. Although the actual process also requires water, a simplified equation (with rust shown as iron(III) oxide (Fe2O3) …
4. ### CHEM

Could you please tell me if these are right?
5. ### Chemistry

Iron(III) oxide is formed when iron combines with oxygen in the air. What is the mole ration of Fe used and the mole of Iron(iii) oxide produced?
6. ### Chemistry

This isn't exactly a homework question, I'm just trying to understand the concept we learned today... So say we had: 4Fe + 3O2 → 2Fe2O3 + 1.65 x 10^3 kJ Does that mean for every 4 mol of Fe, 3 mol of O2, and 2 mol of Fe2O3 we …
7. ### Chemistry

4Fe + 3O2 -> 2Fe2O3 + 1.65E3 kJ  C) what is the enthalpy change for the formation of 23.6 g of iron(iii) oxide?
8. ### chemistry

Calculate the temperature at which it is thermodynamically possible for C (s) to reduce iron(III) oxide by the reaction: 2Fe2O3 (s) + 3 C (s) ---> 4Fe (s) + 3CO2 I don't need a specific answer, but I'm not sure how to approach the …
9. ### Thermochemistry

My question is more conceptual. It is expressed in a series of two problems: What energy change occurs when 1.2 moles of methane combust with an enthalpppy change of -434 KJ?
10. ### Chemistry

When iron rusts in air, iron (III) oxide is produced. How many moles of oxygen react with 7.2 mol of iron in the rusting reaction?

More Similar Questions