<u>Answer:</u> For the given equation, only iron has the value of
equal to 0 kJ.
<u>Explanation:</u>
Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. It is represented as 
The equation used to calculate enthalpy change is of a reaction is:
![\Delta H^o_{rxn}=\sum [n\times \Delta H^o_f(product)]-\sum [n\times \Delta H^o_f(reactant)]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H%5Eo_f%28product%29%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H%5Eo_f%28reactant%29%5D)
For the given chemical reaction:

The equation for the enthalpy change of the above reaction is:
![\Delta H^o_{rxn}=[(1\times \Delta H^o_f_{(Fe(s))})+(3\times \Delta H^o_f_{(CO_2(g))})]-[(3\times \Delta H^o_f_{(CO(g))})+(2\times \Delta H^o_f_{(Fe_2O_3(s))})]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Brxn%7D%3D%5B%281%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28Fe%28s%29%29%7D%29%2B%283%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28CO_2%28g%29%29%7D%29%5D-%5B%283%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28CO%28g%29%29%7D%29%2B%282%5Ctimes%20%5CDelta%20H%5Eo_f_%7B%28Fe_2O_3%28s%29%29%7D%29%5D)
The enthalpy of formation for the substances present in their elemental state is taken as 0.
Here, iron is present in its elemental state which is solid.
Hence, for the given equation, only iron has the value of
equal to 0 kJ.
Answer:
a. magnesium
b. nitrogen
Explanation:
Barium and magnesium are both in 2nd group, so most similar compounds.
Nitrogen - 15 group, so it forms least similar to barium compound.
<span>Like the previous post states, the number of valence electrons (typically the group number for nonmetals)relates directly to the number of covalent bonds available. Additionally, when you exceed this number you create a cation and when you are less the number of potential bonds, you have created a anion.
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Answer:
158g
Explanation:
To calculate the "weight" (mass) of ethyl alcohol, we have to use this formula:
- Density will have units of gmL when dealing with a liquid or units of gcm3 when dealing with a solid.
The mass has units of grams, g.
The volume will have units of mL or cm3
We are given the density and volume, both of which have good units so all we have to do is rearrange the equation to solve for the mass:
density×volume=massvolume×volume
Density×Volume = Mass
0.789gmL×200.0mL
Thus, ethyl alcohol weighs 158g.