Please show me how to work! thanks
When Snno2(s) is formed form the comustion of gray tin, the reaction enthalpy is -578.6 kJ, and when white tin is burned to form SnO2(s), the reaction enthalpy is -580.7 kJ. Calculate the reaction enthalpu for Sn(gray)-->Sn(white)
**SNO2(s)
Sngrey + O2 ==> SnO2 -578.6
SnO2 ==> Snwhite + O2 580.7
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Add the two equations
Sngrey ==> Snwhite
I have turned equation 2 around and changed the sign of dHf.
To calculate the reaction enthalpy for the conversion of gray tin (Sn(gray)) to white tin (Sn(white)), we can use the concept of Hess's Law.
Hess's Law states that the overall enthalpy change of a reaction can be calculated by considering the enthalpy changes of a series of related reactions. In this case, we can use the enthalpy changes of the combustion reactions of gray tin (Sn(gray) + O2 -> SnO2) and white tin (Sn(white) + O2 -> SnO2).
The enthalpy change for the combustion of gray tin is given as -578.6 kJ, representing the enthalpy change when 1 mole of gray tin is burned in excess oxygen to form 1 mole of SnO2.
The enthalpy change for the combustion of white tin is given as -580.7 kJ, representing the enthalpy change when 1 mole of white tin is burned in excess oxygen to form 1 mole of SnO2.
To calculate the enthalpy change for the conversion of gray tin to white tin (Sn(gray) -> Sn(white)), we can subtract the enthalpy change for the combustion of white tin from the enthalpy change for the combustion of gray tin:
Enthalpy change = Enthalpy change of gray tin - Enthalpy change of white tin
= -578.6 kJ - (-580.7 kJ)
= -578.6 kJ + 580.7 kJ
= 2.1 kJ
Therefore, the reaction enthalpy for Sn(gray) -> Sn(white) is 2.1 kJ.
It's important to note that the reaction enthalpy is usually expressed per mole of the reaction occurring. In this case, the enthalpy change is 2.1 kJ per mole of gray tin converted to white tin.