Answer: The standard enthalpy of formation of 
is -252.1 kJ/mol.
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
![\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactantss}]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Bn%5Ctimes%20H_f_%7Bproducts%7D%5D-%5Bn%5Ctimes%20H_f_%7Breactantss%7D%5D)
Putting the values we get :
![\Delta H=[2\times H_f{Fe}+3\times H_f{H_2O}]-[1\times H_f{Fe_2O_3}+3\times H_f{H_2}]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B2%5Ctimes%20H_f%7BFe%7D%2B3%5Ctimes%20H_f%7BH_2O%7D%5D-%5B1%5Ctimes%20H_f%7BFe_2O_3%7D%2B3%5Ctimes%20H_f%7BH_2%7D%5D)
![67.9kJ=[(2\times 0)+(3\times H_f{H_2O})]-[(1\times -824.2kJ/mol)+3\times 0kJ/mol)]](https://tex.z-dn.net/?f=67.9kJ%3D%5B%282%5Ctimes%200%29%2B%283%5Ctimes%20H_f%7BH_2O%7D%29%5D-%5B%281%5Ctimes%20-824.2kJ%2Fmol%29%2B3%5Ctimes%200kJ%2Fmol%29%5D)
Thus standard enthalpy of formation of is -252.1 kJ/mol.
The lewis structure is helpful in showing how the bonding between atoms of a molecule are. The lewis structure of ammonia would be that the nitrogen atom will share three pairs of electron with the three hydrogen atoms leaving nitrogen to have 1 lone pair.<span />
The electron bit would be 2 and you could colour in 4 boxes:) I had the same question as this and I got it correct
B
We can perceive this question as a vector (which has both magnitude and direction). The magnitude is the displacement and the direction is where they are headed.
Explanation:
The displacement (magnitude of the vector) for Callie, which is also equal to the distance, is; 4m + 3m = 7m while that of Sue is 5m. Therefore the displacement for Callie is greater than Sue’s.
Nonetheless the direction in the vector is the same, which is towards point C.
Learn More:
For more on vectors;
brainly.com/question/12006588
brainly.com/question/11823989
#LearnWithBrainly
it will float because it is not heavy enough
