Thursday
March 26, 2015

Homework Help: Chemistry

Posted by Chris on Wednesday, January 31, 2007 at 8:40pm.

Given
2Al2O3 (s) --> 4Al(s) + 3O2 (g) (standard enthalpy change= 3351.4 kJ)

a) What is the heat of formation of aluminum oxide?

How do I find heat of formation from standard enthalpy change? I know how to do it when I'm given enthalpy, but they aren't the same thing- correct?

Also, if this question gave me delta-H, I know that the heat of formation for 4Al = 0 and 3O2 = 0 because they are elementary species. This would leave me with 2Al2O3 = delta-H = x (whatever delta-H is) However, since I have 2 moles of 2Al2O3, would I have to divide delta-H by 2? Sorry if that was confusing.

The delta H for the reaction listed is just the reverse of the heat of formation. So add a negative sign to make it -3351 kJ for the reaction, then divide by 2 to make it 1/2*-3351 = 1676 kJ/mol.

Answer this Question

First Name:
School Subject:
Answer:

Related Questions

College Chemistry - Given: 2Al2O3 (s) 4Al (s) + 3O2 (g) įH = 3351.4 kJ, what is...
chem - a considerable amount of heat is required for the decomposition of ...
chem - for 2Al2O3----> 4Al(s) + 3O2 the question is what is the heat change ...
chemistry - A scientist measures the standard enthalpy change for the following ...
chemistry - A scientist measures the standard enthalpy change for the following ...
Chemistry - If calcium carbide has a standard enthalpy of formation of -59.8 kJ/...
chemsitry - c. Use the enthalpy diagram provided above and apply Hessís Law to ...
chemistry - A scientist measures the standard enthalpy change for the following ...
chemistry - A scientist measures the standard enthalpy change for the following ...
Chemistry - Calculate the amount of heat released in the complete combustion of ...

Members