2)Which of the following equations represents a reaction for which the delta H can be called a standard enthalpy of formation, delta Hf?
a) FeO(s) + CO2(g) -> FeCO3(s)
b) 1/2 N2(g) + 2 O(g) -> NO2(g)
c) 2 Na(s) + Cl2(g) -> 2 NaCl(s)
d) Ba(s) + N2(g) + 3 O2(g) -> Ba(NO3)2(s)
e) more than one of the four equations above are standard enthalpies of formation.
I chose answer e.
For number 2 did you mean that my answer choice of e was correct or that just equation d is correct? Thank you for your help!!
Just d is correct. Which other one did you think was correct.
a. compounds on the left rule it out.
b. O not standard; rule it out.
c. more than 1 mole not allowed; rule out
d. ok.
e. only d is correct.
O ok I thought that b was correct also but I see now why it is not.
To determine which equation represents a reaction for which the delta H can be called a standard enthalpy of formation, we need to understand the concept of standard enthalpy of formation.
The standard enthalpy of formation (ΔHf) refers to the enthalpy change when one mole of a compound is formed from its constituent elements, all in their standard states, under standard conditions of temperature and pressure (298 K and 1 atm).
We can determine whether the given equations represent standard enthalpies of formation by analyzing whether the reactants in the equation are in their standard states and whether the product is one mole of a compound.
Let's evaluate each equation:
a) FeO(s) + CO2(g) -> FeCO3(s)
In this equation, the reactants (FeO and CO2) are not in their standard states, thus not representing a standard enthalpy of formation.
b) 1/2 N2(g) + 2 O(g) -> NO2(g)
In this equation, the reactants (N2 and O) are not in their standard states, thus not representing a standard enthalpy of formation. Additionally, the product NO2 is not one mole of a compound.
c) 2 Na(s) + Cl2(g) -> 2 NaCl(s)
In this equation, the reaction represents the formation of 2 moles of NaCl from their constituent elements, which are all in their standard states. This equation represents a standard enthalpy of formation.
d) Ba(s) + N2(g) + 3 O2(g) -> Ba(NO3)2(s)
In this equation, the reaction does not represent the formation of one mole of a compound from its constituent elements. Therefore, it does not represent a standard enthalpy of formation.
Based on the analysis above, only equation c) represents a reaction for which the delta H can be called a standard enthalpy of formation (ΔHf). Therefore, the correct answer is d) None of the above.
It seems there was a typo in the question, and you meant to select d) instead of e).